WEBVTT 00:00.000 --> 00:08.200 Hello everyone, welcome to Lock Bypass Village and welcome to my talk all about alarms and access control systems and how to hack them. 00:08.280 --> 00:20.000 This talk is going to be fairly high level, so we'll talk about the full range of hardware that is common to experience in the wild, as well as the general attack methodologies that we can use against them. 00:20.000 --> 00:32.300 We won't go too much into the weeds about specific makes and manufacturers and specific attacks that can be used, but that is generally quite inferable from what we'll be talking about today. 00:32.700 --> 00:43.180 So, let's start by considering a simple door, purely mechanical, and this is what all of the rest of Lock Bypass Village is about, various ways that we can get through this door if it is locked. 00:43.300 --> 00:50.200 So, you might be able to pick the lock, use an under-the-door tool on the handle, you might be able to remove the hinges, etc. 00:50.700 --> 00:54.820 What happens if we want to make this an access-controlled door? 00:55.480 --> 01:14.420 At the bare minimum, we'll need to add some sort of credential reader, and some sort of electronically-controlled actuator that will lock and unlock the door, and some sort of controller that will determine if the credential is valid, and if so, go ahead and unlock that door. 01:14.420 --> 01:29.300 At this point, it's very easy to add a little bit of sensing to sense anomalies, such as brute force entry or bypassing being done, and that can be done quite cheaply by adding a magnetic read switch. 01:29.300 --> 01:46.460 So, this bottom unit here is a simple magnet, and in the top, there is a wire that's going to be balanced within a magnetic field, and if the field becomes too strong or too weak, it will break or make an electrical contact, letting the controller know that the magnet has moved. 01:46.460 --> 01:50.080 The purpose of this is to detect when the door has opened. 01:51.000 --> 01:56.640 So, one problem with doing that is if someone's trying to exit the door. 01:56.640 --> 02:03.080 If they're trying to enter, they're going to swipe the credential, the controller will unlock the door, it detects an open, that's okay. 02:03.080 --> 02:16.260 If they're trying to exit, it's now going to trip this type of sensor here, which is a request-to-exit sensor, is the general term, and very frequently what we see with these is passive infrared technology being used. 02:16.260 --> 02:32.000 So, it will detect the black-body emission spectrum of the human body on the secure side of the door, meaning someone's trying to exit, and if that's the case, if it detects that, and then it detects that the door opens, that is okay, that's a valid exit sequence of events. 02:32.000 --> 02:46.940 If, however, it detects that the door has opened, there was no valid credential swiped, and no one was standing on the secure side of the door waiting to exit, that is an alarm condition, and that indicates that the door might have been forced open, might have been bypassed open, 02:46.940 --> 02:47.660 etc. 02:47.660 --> 02:51.260 But it will send that alarm to the access controller. 02:51.400 --> 03:02.240 We're missing one more component that we need if that happens, which is that the access controller needs some way to communicate to the outside world that there's an alarm that needs to be investigated. 03:02.260 --> 03:06.640 So there's going to be some line out from the access controller to do that. 03:06.640 --> 03:09.400 There's usually going to be a line in as well. 03:09.400 --> 03:14.520 So this way we can, say, set what the public building hours are so that the door will be open. 03:14.520 --> 03:20.320 This way we can set who is allowed to access it, we can revoke credentials as necessary, etc. 03:21.000 --> 03:26.700 So let's look at some of the technologies that are available for these various parts of the system. 03:26.700 --> 03:34.460 For the credential reader itself, we have RFID-based, which is the most modern and generally the most secure. 03:34.860 --> 03:43.360 We have MagStripe, so cards that are encoded with a number in magnetic polarities along the card. 03:43.360 --> 03:47.200 We can use a biometric reader, such as a fingerprint scanner here. 03:47.300 --> 03:58.520 A key code entry system, so instead of being something that the user has or something that the user is, it's something the user knows, so the code. 03:58.720 --> 04:11.080 And we can also have a camera, where some human on the other end of that line is going to look in the camera, see who it is, and make the go or no-go decision of is this person authorized to enter this facility. 04:11.640 --> 04:21.080 In terms of technologies available for the actuator, so this one that is the most common by far is a MagStrike, or magnetic door strike. 04:21.120 --> 04:32.980 This plate here is going to be loose and allowed to swing open when the door is supposed to be unlocked, and it will seize up and not move and prevent the door from opening when the door is supposed to be locked. 04:32.980 --> 04:40.020 Over here we have a MagLock, so this larger unit will be mounted to the frame, and this smaller one onto the door. 04:40.020 --> 04:49.080 These will magnetically couple and hold very, very tightly, with generally 2,000 pounds or more of holding force, when the door is supposed to be locked. 04:49.080 --> 04:54.100 And then the system will let them separate when the door is supposed to be unlocked. 04:54.100 --> 05:05.000 We might have an electronically controlled set of handle hardware, so just like how the key can be used to lock and unlock the door, we just have an electronic actuator inside that does the same. 05:05.000 --> 05:12.640 In higher security applications, we might see a turnstile-based system here, so a very good system to prevent piggybacking in after someone. 05:12.640 --> 05:15.120 It only lets one person in at a time. 05:15.120 --> 05:19.520 And we might also see various vehicle control systems as well. 05:20.320 --> 05:25.760 In terms of the sensor, ultimately the goal of this is to detect is the door open or not. 05:25.760 --> 05:33.880 Most commonly we see magnetic-based sensors, so these two are mounted on the frame of the door, on the inside or outside of the frame. 05:34.000 --> 05:36.500 They should be mounted on the secure side. 05:36.500 --> 05:42.100 If they're mounted on the insecure side, that then opens up a whole host of attacks that we can use. 05:42.140 --> 05:48.960 We also have magnetic sensors that are mounted within the frame, so drilling a hole in the frame and at the top of the door. 05:48.960 --> 05:52.140 To mount both the sensor and the magnet that goes with it. 05:52.300 --> 05:59.200 We can use optical-based sensors, so detecting light or dark where the door is supposed to be. 05:59.200 --> 06:05.720 Some hinges are capable of sensing what their position is and reporting that back. 06:05.720 --> 06:11.420 And as well we have some mechanical-based sensors, so this arm getting tripped when the door is in the correct position. 06:12.200 --> 06:18.380 In terms of the request-to-exit sensor, that is often done with a passive infrared sensor like these two here. 06:18.380 --> 06:24.560 Sometimes it's a button that the user pushes to cause that door to unlock and allow egress. 06:24.600 --> 06:37.980 It might also be the exit hardware itself, so pushing a push bar there that will mechanically unlatch, will also tell the controller that someone is trying to exit and this is not an alarm situation. 06:37.980 --> 06:42.900 And finally, in very high security environments, we might see another credential reader. 06:42.900 --> 06:50.920 So you actually have to swipe your credential to say that yes, I am an authorized user and I am exiting this facility normally. 06:50.920 --> 06:56.080 In an emergency situation, there of course do need to be overrides, but that could cause an alarm. 06:56.740 --> 06:59.960 So this is what these tend to look like in the field. 06:59.960 --> 07:08.900 You'll see your request-to-exit sensor mounted here, and then at the bottom we have our in-frame type magnetic contact sensor. 07:08.900 --> 07:12.900 On the door side, here is the magnet that goes along with it. 07:14.580 --> 07:21.600 So this is the general setup that we need, at a bare minimum, for an access control and alarm system. 07:21.620 --> 07:33.920 We can add a few peripherals, such as there might be a mechanical key switch that can be used to turn the door on and off, so to lock the door or unlock it, say for public building access hours. 07:33.920 --> 07:36.360 This might be used by a security guard. 07:36.360 --> 07:45.580 It allows someone with much less training and much less complexity of integration to the network controller to actually lock and unlock the system. 07:45.920 --> 07:52.140 We might also see accessibility features, such as buttons that will trigger an automatic door opener. 07:52.140 --> 08:04.960 Generally, the button on the outside, or the unsecure side of the door, will only open this door if a credential has been swiped validly, or if the door is supposed to be unlocked, such as during building public open hours. 08:04.960 --> 08:16.680 On the inside, that's generally not required, and the mere act of pressing this button will cause the mag strike to unlock, and the door to then automatically open. 08:16.680 --> 08:29.240 And finally, we also see it tied into the fire system in a lot of cases, because if we're using a mag lock, there is no mechanical override to cause that to unlock. 08:29.240 --> 08:33.560 If it's a mag lock, the access controller must unlock it for us. 08:33.560 --> 08:36.160 If it doesn't do that, that door will stay locked. 08:36.160 --> 08:40.660 That can be a fire hazard if someone needs to exit in an emergency situation. 08:40.660 --> 08:48.980 So the way that that is done is, by code, there must be a fire alarm pull near any mag locked door that is a fire exit. 08:49.200 --> 08:56.400 And if the fire alarm is triggered, that mag lock is then going to open and allow egress from the building. 08:56.560 --> 09:00.780 Because of that, there needs to be a tie-in from the fire alarm system. 09:01.680 --> 09:05.380 All of these aspects require power. 09:05.460 --> 09:09.080 So sometimes there's separate power required for credential readers. 09:09.080 --> 09:19.720 There always is for the access controller, and the fire controller, and large power draw components, such as a door opener here. 09:19.720 --> 09:32.120 We can disable the alarm, or breach the door entirely, causing it to open, by attacking any of the hardware, power, or comms lines in this relatively complicated system. 09:32.120 --> 09:34.680 So let's talk about how we can do that. 09:34.760 --> 09:36.720 Starting with the power. 09:36.840 --> 09:45.800 We can cut power to the access controller, and when that happens, by code, things like mag locks need to fail open. 09:45.800 --> 09:48.680 We can likewise cut power to the fire controller. 09:48.680 --> 09:51.580 That, of course, has life safety implications. 09:51.740 --> 10:05.220 But it will also cause the mag lock to open, because if the fire controller goes offline, then there's no way to effectively cause egress if that becomes necessary in an emergency. 10:05.360 --> 10:08.100 Incidentally, it is very, very difficult to kill power to this. 10:08.100 --> 10:11.000 It has all sorts of backups available. 10:11.000 --> 10:22.300 And then we can also kill power directly to the mag lock, and to other peripherals of the system that might be able to cause us entry, or disable the alarm. 10:23.000 --> 10:29.360 We can attack the door contact sensor, so if it doesn't sense that that door opens, it will not trigger an alarm. 10:29.740 --> 10:32.240 And we'll talk about a number of ways to do that. 10:32.820 --> 10:40.480 We can attack the request to exit sensor, so if it thinks someone's trying to exit, then even if it does detect the door opens, it will not trigger an alarm. 10:40.480 --> 10:45.700 We can attack the mag strike, so to cause the door to open up. 10:46.300 --> 10:53.440 We can attack the credential reader, to cause it to think that a valid credential has been swiped, or to clone a credential, etc. 10:53.900 --> 10:58.560 We can attack the inside, the secure side, accessibility button. 10:58.560 --> 11:09.940 So if that gets pressed, or the controller thinks it's been pressed, it's going to unlock the door, open the door, and disable any alarm that might come along with that otherwise. 11:09.940 --> 11:14.960 We can attack this key switch, make the controller think that the door is supposed to be open. 11:15.340 --> 11:22.480 We can attack the fire system, make it think that we are in an alarmed state, and so the mag locks need to open. 11:22.640 --> 11:33.840 We can attack the line out, so most simply by blocking any attempted communication of an alarm from getting out to an external control center. 11:33.840 --> 11:41.140 We can attack the line in, so by telling the controller that my credential is a valid one and you should let it in. 11:41.140 --> 11:49.140 Or by, say, telling the controller that the building public hours are 9-5, as well as 2-2.01am on Friday nights. 11:49.140 --> 11:53.360 And then we can come back at that specific time, and it will just let us in. 11:53.360 --> 12:06.240 We can attack the controller itself, so it is, of course, a fairly complicated piece of ICS equipment, and is vulnerable to all sorts of cyber attacks that are the subject of all the other DEFCON villages. 12:07.540 --> 12:15.840 We can also attack all of the comms lines, everywhere throughout this, and that's something that we'll talk about fairly extensively in the rest of this talk. 12:15.840 --> 12:21.700 And there's one more attack factor that we can take in this overall system. 12:21.700 --> 12:25.040 Take a stare at it and see if you can figure out what it is. 12:25.080 --> 12:29.060 The answer is... the door itself. 12:29.060 --> 12:40.280 If we can cause some way to mechanically get ourselves through this door, without interacting with all of this other equipment, then we've effectively disabled the alarm. 12:40.420 --> 12:44.700 So, one very brute force way is to saw a hole in the middle of the door. 12:44.700 --> 12:46.600 There are other options as well. 12:46.600 --> 12:50.340 So, many doors have these vent louvres in them. 12:51.040 --> 12:56.080 Frequently, we see these with the screws facing the outside, which is a terrible security decision. 12:56.080 --> 12:59.460 You can just unscrew that, and then slide on through. 12:59.760 --> 13:03.280 Doors with windows in them, as well, can be attacked. 13:03.340 --> 13:06.440 And so you can go through the window to achieve a similar effect. 13:06.440 --> 13:09.500 And this is something that is seen on occasion. 13:09.700 --> 13:12.220 So here's an example of a residential burglary. 13:12.220 --> 13:16.340 These burglars have seen the contact sensors on the doors. 13:16.340 --> 13:19.460 They know that they can't actually cause these doors to open. 13:19.720 --> 13:22.080 So what they're going to do instead is break the window. 13:22.080 --> 13:28.500 And rather than reaching through and depressing the handle, they're just going to climb through these wide open windows. 13:28.540 --> 13:30.500 And so we see them doing that now. 13:30.560 --> 13:37.280 Incidentally, those very wide open windows make this particular house more vulnerable to burglaries. 13:37.280 --> 13:44.640 Because they can see all of the valuables that are inside, where they are, what the alarm system is like, etc. 13:44.640 --> 13:47.740 It's a much less risky endeavor for them. 13:48.060 --> 13:50.200 And so the burglars are just reaming that out. 13:50.200 --> 13:53.020 And we'll see them crawl through in a minute. 13:57.910 --> 14:02.990 And just like that, they are in, bypassing the alarm system. 14:04.950 --> 14:07.930 So let's talk about the communications lines. 14:07.930 --> 14:15.170 Every aspect on the system has communications lines going into it or coming out saying, should I be enabled or not? 14:15.170 --> 14:16.850 And we can attack those. 14:16.850 --> 14:25.010 We'll focus on the magnetic contact sensor because it's the one that's sort of most readily attackable. 14:25.010 --> 14:27.970 But this applies to all the others as well. 14:28.410 --> 14:34.090 So in the case of the contact sensor, we have a normally closed situation. 14:34.090 --> 14:37.270 That's normally what we see for security alarms. 14:37.270 --> 14:41.670 And that is that in the secure state, the door is closed. 14:41.670 --> 14:43.650 That means that the circuit is closed as well. 14:43.650 --> 14:45.530 So it's a short circuit. 14:45.530 --> 14:47.370 We have power flowing. 14:47.470 --> 14:50.970 And if that gets interrupted, we know it's an alarm state. 14:50.970 --> 14:53.930 So if the switch opens up, that becomes an alarm. 14:54.090 --> 14:57.770 And what we can do is jumper the line from one to the other. 14:57.770 --> 15:01.730 And that way, if that switch opens up, it will not send an alarm. 15:02.970 --> 15:06.670 In the normally open state, we have the line is broken. 15:06.670 --> 15:09.890 So the switch is open and there's no power flowing. 15:09.890 --> 15:11.630 And that's the normal situation. 15:11.730 --> 15:14.130 When we open the door, the switch closes. 15:14.150 --> 15:17.310 And then the controller sees low impedance and sends an alarm. 15:17.310 --> 15:19.250 We can just then cut that line. 15:19.250 --> 15:23.630 And at that point, it simulates the switch being open and the door being closed. 15:23.790 --> 15:27.050 No matter what we do at the switch end. 15:27.490 --> 15:29.670 What can we do to defend against these? 15:29.670 --> 15:35.230 Most commonly, what we see is having end-of-line resistors. 15:35.230 --> 15:41.970 So the effect, as seen by the controller, is the door switches between two different resistances. 15:41.970 --> 15:56.330 The way we accomplish this in practice, rather than having a three-lead switch, usually is having a series resistor that runs on one of the lines in series with it, and a shunt resistor that crosses across those two lines. 15:56.330 --> 16:00.970 So we always have some power flowing through the shunt resistor, even when that switch is closed. 16:01.090 --> 16:07.490 And when the switch is open, it must flow through that series resistor as well. 16:07.710 --> 16:11.650 There are ways to defeat that, and we'll talk about those in a minute. 16:11.650 --> 16:17.690 But the absolute best that we can do is an encrypted digital line that has denial-of-service detection heartbeats. 16:17.690 --> 16:21.210 And we'll talk a little bit more about digital lines shortly. 16:21.210 --> 16:34.830 What we'll look at first is a game that we're actually releasing this year for DEFCON Safe Mode with Lock Bypass Village that will let you practice rewiring alarms to disable the actual alarm on the end of them. 16:35.590 --> 16:42.470 So this is mirroring a physical demonstration that we were planning to do at DEFCON in real life, but of course that can't happen. 16:42.470 --> 16:45.510 So this is the best that we can do as a surrogate. 16:45.510 --> 16:52.390 What we have here is a simulated door with its contact sensor and an alarm controller here. 16:52.390 --> 16:59.830 We'll talk about what a zone is in a minute, but it means for the sake of this demonstration, a single door. 16:59.830 --> 17:07.230 We have a supply current of 25 milliamps and zero volts that are coming across that system. 17:07.230 --> 17:13.410 That tells us that there is a short circuit here and an equivalent resistance of zero. 17:13.410 --> 17:17.090 So a short circuit, and that is an alarm status of OK. 17:17.090 --> 17:21.190 If we open this door, we now have an open circuit. 17:21.190 --> 17:23.130 So the circuit has been broken. 17:23.350 --> 17:29.470 The line voltage becomes indeterminate because there's no current going through, and this is an alarm state. 17:29.470 --> 17:33.230 So it's simply looking for short circuit or open circuit. 17:33.290 --> 17:48.110 In order to defeat this system, what we can do is cut the line and strip it, and then take a jumper cable and hardwire those two wires together. 17:48.270 --> 17:51.070 And so now we have an OK state. 17:51.070 --> 17:56.190 We see a short circuit on the controller end, and the door is totally disconnected. 17:56.190 --> 18:02.750 So we can open and close that door all we want, and the controller will have no idea. 18:03.270 --> 18:09.030 You'll notice that when I initially cut that line to strip those wires, that did trigger the alarm. 18:09.030 --> 18:10.910 We wouldn't generally want to do that in the field. 18:10.910 --> 18:22.890 The way to get around that is using this tap piece of hardware, so we would actually strip just the outer sheath and then tap the inner wires and bridge those taps together. 18:23.230 --> 18:27.470 So that's something that you can practice for yourselves using this game. 18:28.350 --> 18:35.730 In the next situation of a normally open switch, so we have an open circuit when the door is closed. 18:35.730 --> 18:44.910 When we open the door, that's then going to complete this circuit, and we now see zero ohms, so a short circuit situation. 18:44.910 --> 18:47.810 The way that we defeat this is very simple. 18:48.250 --> 18:49.390 Cut the line. 18:49.490 --> 18:54.450 And now we have an open circuit, no matter what happens, because the line is cut. 18:55.090 --> 18:59.770 The most secure situation is where we have these end-of-line resistors. 18:59.770 --> 19:05.190 So we have a series resistor here, and a shunt resistor connecting these two lines there. 19:05.190 --> 19:11.970 And that happens right at the end of the line, right before the sensor exists. 19:12.210 --> 19:25.130 And so what happens now is, if I have an equivalent resistance of 45 ohms, when the door is closed, it jumps up to 500 when the door is open, so we have our OK state and our alarm state. 19:25.190 --> 19:34.950 If I were to cut the line, it's going to detect an open circuit, which is different than those other two states, and that indicates tampering has happened on the line. 19:34.950 --> 19:47.870 Likewise, if I go through and actually bridge that connection, it's going to detect a short circuit, which it also normally would never see, because of these end-of-line resistors. 19:47.870 --> 19:56.310 So that also indicates tampering along that line, and that would send a different alarm, that hopefully would be responded to with greater severity. 19:56.310 --> 20:13.990 The way that we can defeat that is by adding our own resistances along the line, and so there's a number of ways that you can play around with doing that in these games, such as adding potentiometers that you can then control, as well as a whole slew of resistors. 20:13.990 --> 20:28.670 And you can play around with that to get a situation where you can both disable an alarm once, as well as go through the whole situation of disabling an alarm, where it never actually sent an alarm while you were tampering with those wires. 20:28.670 --> 20:34.250 So that's something that you can play with as well in the Lock Bypass Village this year. 20:37.820 --> 20:46.960 So let's talk a little bit about digital communications lines, and the various attacks and defenses that exist on those. 20:47.260 --> 20:51.660 So a digital communication line is going to be sending a 0 or a 1. 20:51.660 --> 20:59.080 So here's an example of 0101001101 being sent in the ideal case. 20:59.120 --> 21:17.420 Communications lines have some parasitic capacitance, so because those lines are two plates close together effectively, just very long, it acts like a capacitor, and that causes some capacitive effects here, so we see the line getting charged up and then charged back down. 21:17.420 --> 21:33.400 It also has some parasitic inductance, so that line is going to induce a magnetic field around it as the electric current in it changes, and so as a result we see this higher-order Fourier effect that happens on the line. 21:33.400 --> 21:41.620 And so the combination of those two is this pattern that we see down here, a slightly distorted digital signal. 21:43.380 --> 21:44.800 There's also noise. 21:44.800 --> 21:50.320 So there's noise in the environment, there's magnetic and electric noise, and that's going to inductively couple with the line. 21:50.560 --> 21:56.540 And there's noise in the sender and the receiver electronics as well, all of that contributes. 21:56.700 --> 22:09.540 And so we're going to take this slightly distorted signal from our nonlinear line, and we're going to add onto it this noise, and we get a further distorted electrical signal. 22:09.540 --> 22:17.900 This, as you can see, would still be relatively easy for the receiver to decode and determine what bits were being sent at what time. 22:18.100 --> 22:22.240 Noise, though, is a somewhat powerful phenomenon. 22:22.260 --> 22:32.660 As the amplitude of the noise relative to the amplitude of the signal increases, the noise starts to overtake the signal until the signal is no longer decipherable. 22:32.660 --> 22:35.900 And that's a situation where we have a breakdown of communications. 22:35.900 --> 22:45.620 That's something that is often the case just naturally, but it can also be used by an attacker to cause a denial of service. 22:45.980 --> 22:58.600 And mathematically, what we see is the 0 bit is going to form some normal distribution, normal because the noise usually is Gaussian, and the 1 as well is going to do that. 22:58.600 --> 23:09.080 As the noise increases, these distributions widen until determining which one is which becomes very difficult because this overlap becomes huge. 23:09.780 --> 23:15.240 So how can the red team attack a digital communication line knowing bad information? 23:15.640 --> 23:20.000 So, to attack confidentiality on the line, they can tap that wire. 23:20.000 --> 23:26.860 That can be with a physical tap, like the one that we looked at when we were attacking the analog alarm wire lines. 23:26.860 --> 23:36.020 It can also be with an inductive-based tap, so just listening for RF frequency generated by what that line is communicating on. 23:36.020 --> 23:43.800 To attack integrity, they can introduce packets on the line, so tapping into it and then sending data down. 23:43.800 --> 23:45.980 And to attack availability, this is the easiest. 23:45.980 --> 23:48.180 They can introduce noise. 23:48.820 --> 24:03.820 The defenses against this is you want to physically shield the line, and that's going to help both stop tapping as well as sending power down the line, sending rogue signals down the line. 24:04.460 --> 24:12.120 You can encrypt the digital signal, so that will then prevent both confidentiality and integrity attacks. 24:12.360 --> 24:26.300 And to protect availability, you want to send heartbeats, so that the line can at least detect if it's being denied service, and that will then let you respond appropriately. 24:26.300 --> 24:31.100 So a denial-of-service attack in a very secure environment is the same as an alarm. 24:31.100 --> 24:36.560 It needs to be responded to as if it were an alarm, because it could be an attacker doing this on purpose. 24:38.080 --> 24:46.260 In the wireless world, what we have is a slightly varied situation. 24:46.400 --> 24:50.880 So we can't put a DC current across empty space. 24:50.920 --> 24:53.600 That's because of the laws of physics. 24:53.600 --> 24:56.480 And the laws of the land further constrain what we can do. 24:56.480 --> 25:01.660 We must act within a certain frequency band, so we don't interfere with all the other frequency bands. 25:02.380 --> 25:12.480 And so there's a number of ways that we can use what's called a carrier frequency, to send a digital signal along through the air in the wireless world. 25:12.860 --> 25:21.180 There's frequency modulation, or frequency shift keying, that you're familiar with from radios, where we change the frequency depending on if it's a 0 or a 1. 25:21.280 --> 25:30.240 We can change the amplitude in an AM digital situation, or we can phase shift based on if it's a 0 or a 1. 25:30.460 --> 25:32.840 Those are the three main ones that we see. 25:32.840 --> 25:35.660 The red team attacks there is for confidentiality. 25:35.660 --> 25:47.840 We just sniff, because these are being broadcast for anyone to intercept, and we can then read what's being sent without any wiretapping required, and read that data. 25:47.860 --> 25:54.600 For integrity, we can transmit new, and we can transmit to overwrite the data that's being sent out. 25:54.600 --> 25:58.220 And for availability, of course, we can jam that signal. 25:58.220 --> 26:08.580 So again, for a wireless alarm, if jamming happens, that's something that we want to treat as an alarm situation in a high security environment. 26:08.580 --> 26:31.740 One interesting aside about FM versus AM is, FM is easier to jam and easier to hijack the signal by sending your own data, because whichever signal in a frequency modulated situation is stronger, by even a small amount, the receiver is going to pick up that signal and only that signal. 26:31.740 --> 26:34.220 With AM, it's going to pick up a mixture of the two. 26:34.220 --> 26:36.920 So you can actually try this with your radio. 26:36.920 --> 26:43.480 If you put it halfway between channels on the FM band, it's going to flip from one to the other. 26:43.480 --> 26:49.580 If you put it halfway between channels on the AM band, you're going to hear both channels blended in with one another. 26:49.580 --> 27:04.360 But in a security situation, with sending signals across the empty space, that means that FM is easier to jam and to take over with integrity-based attacks. 27:04.360 --> 27:06.780 The Blue Team Defense, of course, is encrypt as well. 27:06.780 --> 27:10.380 That is the only way to protect confidentiality. 27:10.380 --> 27:13.120 For integrity, encrypting works for that as well. 27:13.120 --> 27:25.260 We also have the added option of locating where this transmitter is that's trying to take over our communication and trilaterate their position and take them out by various means. 27:25.260 --> 27:30.940 We can, of course, also increase the signal strength to avoid their ability to drown us out. 27:31.060 --> 27:32.900 And for availability, it's very similar. 27:32.900 --> 27:42.580 We can locate and take out the jammer, we can increase our power, and we can also use heartbeats to detect if availability has been compromised. 27:43.480 --> 27:50.260 So that's sort of a very high-level overview of how we can attack digital communications lines. 27:50.260 --> 27:56.660 We'll take a step back to the physical systems that we see on these doors and what can we do about them. 27:56.660 --> 28:14.520 So, for these magnetic read switches, one very sort of brute-force-ish attack is we can literally unscrew the magnet and hold it in place relative to where it was beside the doorframe and then open the door with the magnet staying where it is. 28:14.520 --> 28:30.780 Of course, that's only possible with sensors that are mounted on the outside of the frame, on the unsecure side of the door, but it's a very low-tech attack that, if it's possible, is virtually undetectable by the controller. 28:30.780 --> 28:38.080 We can use a surrogate magnet to maintain the magnetic field while the door opens and the real magnet moves out of place. 28:38.940 --> 28:45.300 And so we actually have another game that we're releasing with Bypass Village that you can practice this on. 28:45.300 --> 28:58.980 So here is our door and we can swing it open and closed and we can see this magnet along the top and we can see the magnetic field that's measured by our sensor up here. 28:58.980 --> 29:15.200 And then we can move a little stick with a magnet on it in and out and around that sensor and we can try to use that to make the controller think that the door is closed when it's actually open. 29:15.280 --> 29:25.980 And so if we get it to the right place here, it now thinks that that's the case and as we close the door, we can now open and close it without actually triggering that alarm. 29:25.980 --> 29:31.500 So that's something that you can play around with yourselves in this game that we are releasing. 29:33.240 --> 29:52.960 In terms of the defenses available to the blue team, using an in-frame magnetic sensor helps a lot and putting it on the secure side also helps to avoid these attacks being mechanically possible and we can make them more difficult by using what's called a balanced magnetic switch. 29:52.960 --> 30:03.360 So it doesn't just look for the presence of a magnetic field above a certain intensity, it looks for the presence of a magnetic field above a certain intensity but below another one. 30:03.360 --> 30:18.880 So if the field is too strong, it's also going to set off that alarm and it makes it a whole lot harder to actually use this surrogate magnet attack and that's something that you can also practice how to defeat those systems with the game that we are releasing. 30:19.520 --> 30:34.340 In terms of the request-to-exit systems, if it's a passive infrared, you can send hot or opaque gas or aerosol or something through that door near to the sensor and cause it to think that someone's on the other side. 30:34.340 --> 30:47.560 So there's a fairly well-known attack with taking a can of compressed air, turning it upside down and squirting it and then that condensation that's created is enough to trigger many low-security PIR sensors. 30:47.560 --> 30:54.020 If it's a push-to-exit button or a handle, an egress handle, you can manipulate it from the other side. 30:54.020 --> 31:03.420 So for instance, if this is a request-to-exit sensor and we did an under-the-door tool attack, that would give us two for one, it would also defeat this request-to-exit sensor. 31:05.280 --> 31:20.120 And from the blue team's perspective, using a hybrid PIR and radar sensor is going to help immensely with avoiding people faking a human signature on the other side and using a token reader for egress is incredibly powerful. 31:20.120 --> 31:25.960 It effectively means that we cannot use request-to-exit sensor-based attacks. 31:25.960 --> 31:31.900 We may as well just attack the credential reader on the unsecure side itself. 31:31.900 --> 31:38.100 And so that does increase significantly the difficulty of attacking this particular system. 31:38.100 --> 31:48.080 So using a token reader on the exit side as well is sort of the electronic equivalent of a euro-style double-barreled deadbolt. 31:48.080 --> 31:53.600 Very good design for security purposes, of course at the cost of user convenience. 31:53.840 --> 32:10.280 In terms of PIR sensors, we can set them to have high security settings so that it will only trigger if a person is in the very specific right area and not this giant large range here. 32:10.280 --> 32:16.300 Long range is really meant for convenience and accessibility, so it'll open the door as someone's walking towards it. 32:16.300 --> 32:19.080 It's not meant for security at all. 32:20.080 --> 32:28.140 In terms of attacking these actuators, we can separate the electromagnet slightly. 32:28.140 --> 32:40.700 So if you ever catch the door open that's equipped with a mag lock, you can take a piece of gaffer tape or something fairly thin and put that onto the surface of it. 32:40.700 --> 32:49.320 And that's going to separate those components just enough that it will reduce the holding force from 2,000 pounds down to, say, 50. 32:49.320 --> 32:53.380 At which point the door feels secure, but it can be forced open. 32:53.380 --> 32:56.900 And that's something that you can then come back and do. 32:57.160 --> 33:06.920 And attacks like that, attacking the magnetic-based retaining system, are possible with some designs of mag strikes. 33:08.300 --> 33:11.080 We can attack the comms line and the power. 33:11.080 --> 33:15.700 So in the case of mag locks, they fail unlocked if there's power that's gone. 33:15.700 --> 33:22.440 And we can, of course, attack the comms line to any of these to make the hardware think that the controller is telling it to open up. 33:22.440 --> 33:25.380 And we can use physical bypasses as well. 33:25.380 --> 33:27.740 So mag strikes are often poorly sized. 33:27.740 --> 33:32.560 The dead latch is going to fall into that hole, and we can Lloyd that latch. 33:32.560 --> 33:37.100 If you don't know what that means, check out our Bypass 101 talk. 33:37.480 --> 33:45.840 And the blue team, what they can do to help against these attacks is, of course, shield their communications lines and use hardware that fails in a locked state. 33:46.220 --> 33:51.440 That might not be allowed due to fire code, but wherever possible, you should try to do that. 33:51.900 --> 33:58.000 So here's an example of where we can read that actually there is a mag lock on the other side of the door. 33:58.000 --> 34:01.840 That's what these two bolts are telling us, as well as this conduit coming through here. 34:01.840 --> 34:10.580 What's interesting, though, is this conduit is, of course, the power that's going to that mag lock that is telling it to stay locked. 34:10.640 --> 34:14.640 In this case, turning power on and off is the communications line. 34:14.640 --> 34:23.240 And so we can just unscrew any of these junction boxes here and break that wire, cut that connection somehow. 34:23.240 --> 34:28.320 And this mag lock is going to then fail in an unlocked state, and we can open this door. 34:28.320 --> 34:30.040 Fairly simple attack there. 34:30.040 --> 34:37.400 In the case of this type of hardware, where we have a key switch, we can, of course, pick the lock or do other attacks like that. 34:37.400 --> 34:43.120 We can unscrew the enclosure casing and then jumper out those lines and make it think that the key has been turned. 34:43.200 --> 34:49.140 And, of course, we can perform an attack like that anywhere along the comms line where it's accessible to us. 34:49.220 --> 34:55.440 What the blue team can do to defend against this is put the key switch on the secure side of the door. 34:55.440 --> 34:58.240 I really don't know why this isn't seen more often. 34:59.200 --> 35:10.200 Possibly it's so that the guards can do it when they come on to shift to open up for the first time, but they really should be given a key or some other better credential to get in if that's the case. 35:10.340 --> 35:17.400 And that will avoid this threat entirely, because if you're on the secure side, then you're already in. 35:17.920 --> 35:22.100 You can use a lock of equal or higher security as the facility's front door. 35:22.100 --> 35:34.140 So too often we see crappy weaver locks on these key switches where the front door might be a high security medico, and installing a tamper switch within this box. 35:34.140 --> 35:44.020 So if the controller sees that this box has been opened, it will not honor that if the key switch is turned, no matter what happens, as a bit of a defense with that. 35:44.020 --> 35:46.940 Of course, that can be bypassed as well. 35:46.940 --> 35:49.440 There's loads of ways to bypass tamper switches. 35:50.180 --> 35:55.680 Let's talk a little bit about the communications protocols that are used by the credential readers. 35:55.680 --> 36:12.340 So we have the VIGINT protocol is sort of the original, most well-known one, and it is based off of magnetically charged wires in the card that are going to be placed in either a 0 or a 1 position. 36:12.340 --> 36:19.880 And as we swipe that card, it's going to then have sensors that detect that and give us the data from there. 36:19.880 --> 36:25.800 We can have magnetically encoded information on a mag stripe, which is similar. 36:25.800 --> 36:29.600 And then we can have RFID technologies as well. 36:30.900 --> 36:40.980 Down the line, though, for backwards compatibility, almost every reader and almost every controller still supports the VIGINT protocol. 36:40.980 --> 36:49.700 And that's just to make sure that we can mix and match any reader with any controller, and there's something they can fall back on that will work. 36:50.220 --> 37:10.320 And so that VIGINT protocol looks like, if this is the data that we're sending, so the 0101, 001101 that we saw before, we have our data 0 line and our data 1 line, and they're normally a 1, and we pull either the 0 or the 1 down to a 0 when we want to send a 0 or a 1, 37:10.320 --> 37:11.480 respectively. 37:11.560 --> 37:17.160 So here we send a 0, then a 1, 0, 1, 0, 0, etc. 37:18.740 --> 37:40.840 Because we have that VIGINT protocol in use for backwards compatibility, if we can access those lines, we can then read the VIGINT-encoded data that's being sent, as well as replay or send our own reconstructed packet in that same format. 37:41.000 --> 37:47.840 And that's what the BLE key does, which was released at Black Hat 15 by two very smart individuals. 37:47.860 --> 37:51.400 They designed a piece of hardware that would clip onto the alarm wires. 37:51.400 --> 37:56.440 So we see here the green and the white VIGINT wires, as well as our black ground. 37:56.440 --> 38:03.740 It clips onto that, and it listens to every credential that gets swiped, and it can communicate with your phone via Bluetooth. 38:03.740 --> 38:12.540 And that phone can then get the raw credential data, as well as replay any valid credentials, and cause that door to open on demand. 38:12.540 --> 38:16.640 So that's one particular attack against that communication line. 38:16.640 --> 38:20.500 A good remediation for this is OSDP. 38:20.500 --> 38:30.000 It's one of the... well, it's really the only encrypted communication protocol that we see in somewhat widespread use. 38:30.000 --> 38:36.240 It's still not very widespread, and there are some proprietary systems that will use other encrypted forms as well. 38:36.240 --> 38:38.500 And hook up your damn tamper wires. 38:38.500 --> 38:53.120 So when you remove that credential reader from the wall to get access to the wires behind it, almost all of them, the good ones at least, are equipped with a tamper switch that will send the controller a signal saying, hey, this reader has been removed from the wall. 38:53.120 --> 38:58.800 If that happens, the controller should respond appropriately, set up the appropriate alarms, etc. 38:58.860 --> 39:02.120 All too often, we see that not even hooked up. 39:03.120 --> 39:06.660 So here's a quick example we can take a look at. 39:06.660 --> 39:16.800 We have our reader here, and we can assume that there's some sort of actuator on the other side, very likely a mag lock. 39:16.800 --> 39:27.080 As well as we have an accessibility door here with a visible magnetic strike system, and that will be opened by some other situation. 39:27.260 --> 39:31.000 So there's a couple items that we can notice in the wild. 39:31.000 --> 39:37.440 One thing to note about all of this hardware we've been talking about is it is blazingly expensive. 39:37.600 --> 39:46.600 Here is some of the standard retail costs for what a new construction building might pay for these pieces of hardware. 39:46.600 --> 40:00.900 So things like not hooking up your tamper wires, putting poor quality locks on the unsecure side that can disable the system, not shielding your communication lines and letting those be accessible from the public, etc. 40:01.000 --> 40:15.280 All of those are really simple fixes and very cheap in comparison to the cost of this hardware, and something that really should be looked at if you have a facility that cares about security enough to pay this kind of money for these systems. 40:15.280 --> 40:21.900 But anytime you see a door that's equipped with this equipment, these are the kinds of costs that are involved in actually setting that up. 40:22.720 --> 40:35.980 So we've talked a lot about access controllers determining or giving the go or no-go decision on a door based on a credential swipe and sending an alarm if there is an unauthorized access. 40:36.860 --> 40:41.640 We can also talk about alarm systems, and they are more state-based. 40:42.200 --> 40:48.980 So on a very high level we have three states, an armed state, disarmed, and an alarmed state. 40:48.980 --> 40:52.940 And we can enter the arming and disarming sequence to move between these top two. 40:52.940 --> 40:59.420 If a sensor is tripped when it's armed, it's going to alarm, and then the reset sequence will move us back to disarmed. 40:59.460 --> 41:05.960 In order to attack these systems, our starting state is armed, we're assuming that, since it needs to be attacked. 41:05.960 --> 41:22.340 And the two routes that we can take is we can cause the disarming sequence to be entered or cause the controller to think it has been, and move it to a disarmed state, or we can prevent these sensors from being tripped and prevent it from going into an alarmed state. 41:22.920 --> 41:32.240 So, to give one example of the first type of attack, this is a typical timeline that happens in older, less well-designed systems. 41:32.240 --> 41:34.180 We have our controller here. 41:34.180 --> 41:36.700 The sensor gets tripped as time moves along. 41:36.700 --> 41:46.820 In a normal situation, a normal entry, the disarmed code is entered, the panel enters a disarmed state, and then the timeout happens, but because the code has been entered in time, nothing happens at that point. 41:46.820 --> 41:48.860 The police are never contacted. 41:49.500 --> 42:00.580 If, however, a valid code is not entered in time, then when the timeout happens, the panel will then contact the police, and they will be dispatched to see what's happening with this alarm. 42:01.220 --> 42:19.120 This allows for what's called a crash and smash attack, which is that, if at any point, between the sensor being tripped and the timeout, the panel is rendered inoperable, the communications lines are rendered inoperable, etc., it will then prevent it from sending that call for help out when the timeout happens, 42:19.120 --> 42:22.700 because the panel no longer operates. 42:22.900 --> 42:35.980 This, of course, assumes that your keypad panel is the same as the controller, which in many systems it's not, but many good burglars know which ones are, and which ones are vulnerable to this. 42:35.980 --> 42:38.960 And so that's something that you do see on occasion. 42:39.340 --> 42:44.400 A better way to handle this is to have an intermediary server that's off-site. 42:44.400 --> 42:47.860 As soon as that sensor is tripped, the server is notified. 42:47.900 --> 42:51.880 When the disarm code is entered, that server is notified as well. 42:52.020 --> 43:03.120 If the disarm code is not entered, then when timeout occurs, the server then will dispatch the police without requiring any more communication from the local facility. 43:03.120 --> 43:09.980 That way, if there's a crash and smash attack, and that panel is rendered inoperable, an alarm will still go out. 43:10.480 --> 43:18.380 So that's the disarming sequence, or at least sort of a pseudo-situation to move us to a disarmed state. 43:18.380 --> 43:22.200 We can also prevent the sensor from being tripped. 43:22.200 --> 43:26.580 And there's a load of ways to do that, depending on what type of sensor exists. 43:26.680 --> 43:28.720 So we have a number of different types. 43:28.720 --> 43:37.760 We have cameras that are usually human-operated, but increasingly we have computer vision systems that are going to look for motion where there shouldn't be. 43:37.760 --> 43:46.000 We have these door-open sensors, as well as glass-break sensors are common, so to prevent that through-the-window attack. 43:46.380 --> 43:50.220 We have passive infrared sensors that we looked at for requests to exit. 43:50.300 --> 43:54.040 Those ones we did want to trip, to make the door think someone was exiting. 43:54.040 --> 44:00.200 These ones, as a red team, we don't want to trip, because that will tell the alarm system someone's here and there shouldn't be. 44:00.360 --> 44:05.140 So they detect the presence of a human body infrared spectrum. 44:05.200 --> 44:14.820 And then we have various underground seismic-based systems to detect someone walking on ground, as well as fence-climb sensors that we see on the outside. 44:14.880 --> 44:20.920 Both of these, by the way, are incredibly prone to false positives. 44:20.920 --> 44:25.720 So they are only usually seen in very high-security applications. 44:26.020 --> 44:32.760 In terms of how the controller combines all of these, we have what's known as alarm zones. 44:32.760 --> 44:41.400 So zones are the individual circuits that one or more of these sensors is put on. 44:41.400 --> 44:59.260 So in this case, we have a normally-closed zone that has two magnetic-read sensors on it, a second normally-closed zone that has only one on it, and for normally-closed, we need to wire them in series, and then a normally-open zone that has two wired in parallel. 44:59.620 --> 45:07.780 For security systems, you usually have them wired in series, if not only a single one on a zone, which is generally better. 45:07.780 --> 45:15.120 And then for fire systems, you're going to wire in parallel and have normally-open systems there. 45:15.120 --> 45:22.440 So that is how all of these devices get handled by the controller. 45:22.440 --> 45:31.340 And what that means is if multiple different sensors are on the same zone, the controller cannot tell which one was tripped, just that one of them was. 45:31.340 --> 45:40.860 And so the idea is they generally tend to be aligned in space, so the controller can identify where physically in the facility this alarm is coming from. 45:41.570 --> 45:45.900 So there's a number of specific defeats for each of these. 45:45.960 --> 45:55.320 One that we'll talk about for passive infrared sensors is to block the infrared signature from your body actually reaching the sensor. 45:55.320 --> 46:06.660 So you can use these space blankets that will then reflect the ambient thermal signature back onto the sensor and cause it to not see you. 46:06.660 --> 46:18.940 You have to be very careful with those, because if you touch it with your hand, then your hand is now going to... it won't radiate, but it will conduct through because you're touching it, and that's going to defeat your efforts there. 46:19.160 --> 46:30.920 We've actually found anecdotally that for many of the commercial PIR sensors out there, yoga mats work incredibly well, a lot better than these do, to block your IR signature. 46:30.920 --> 46:41.840 You can move very slowly, because these things have to get a sense of what the environment is, and so if you move slowly, it might think that you are just part of the ambient environment. 46:42.000 --> 46:55.900 You can move out of its focus range, so many of these in facilities that might have animals walking around, which is usually a residential setting, will be set to only focus on above two or three feet on the ground. 46:55.900 --> 47:05.300 That's the default setting in many cases, and in some cases that is just a physical limitation of the device that's being shipped out. 47:05.580 --> 47:14.220 If that happens, you can then effectively get down to that level, away from the focus range, and avoid these entirely. 47:14.220 --> 47:21.940 And as well, passive infrared sensors are much more sensitive to motion across them. 47:21.940 --> 47:25.640 Moving towards and away from them, they're less sensitive towards. 47:25.640 --> 47:30.560 So if you can make your motion in that direction, it will help you avoid being detected. 47:31.080 --> 47:36.620 So here is another example that we see that is no longer available. 47:39.920 --> 47:48.660 So taking a look at one particular hypothetical layout of passive infrared sensors, this is a bad layout. 47:48.660 --> 47:51.560 Take a stare at it and see if you can figure out why. 47:51.900 --> 48:02.300 The reasons are, number one, way at the edge of the range is a large part of the room that is accessible by one of the doors. 48:02.360 --> 48:14.880 And so we can now get around and access large parts of this room through that, as well as this particular door here gives us access to the back of two of the sensors. 48:14.880 --> 48:24.920 And so by doing that, we can then place an IR shield in front of it from behind, and effectively blind them to almost all of the room. 48:24.920 --> 48:37.640 And finally, the way that these are laid out, it allows motion in a towards and away from direction to help avoid it detecting on its more sensitive perpendicular axes. 48:38.700 --> 48:50.780 The last thing I'll actually mention about this particular layout is someone who is entering this room and seeing that this layout is the case, will wonder, well, why are they clustered along this particular wall? 48:50.780 --> 48:56.680 One potential reason might be this shaft here, that X indicates a shaft in the wall. 48:56.680 --> 49:00.640 That's likely a pipe riser shaft through which comms lines run as well. 49:00.640 --> 49:11.280 So if someone can infer from that that the comms lines for these are running through this shaft, they can enter that instead where there are no sensors and cut them off along the comms lines instead. 49:11.340 --> 49:17.860 A better layout surrounds the room and makes sure that all doors are firmly in the coverage range. 49:17.860 --> 49:26.280 And there's no way to get in any of these doors without moving entirely perpendicular to these sensors in their sensitivity direction. 49:26.640 --> 49:31.660 As well, there's no way to get behind any of the sensors, let alone all of them. 49:31.660 --> 49:39.080 And there's no way to get anywhere appreciable within this room without setting off at least one of our motion sensors. 49:39.200 --> 49:40.940 So this is a much better layout. 49:41.840 --> 49:52.200 The last thing that we can look at, and this is getting a little bit more into social engineering, so we'll only touch on it briefly, is attacking the response that happens when an alarm gets sent out. 49:52.440 --> 49:57.860 So when the responding forces are distracted, they might be sleeping, they may be on other calls, etc. 49:57.860 --> 50:03.040 It might just be a human factors problem in the control room, which we see very, very frequently. 50:03.700 --> 50:06.520 They will not respond effectively to an alarm. 50:06.520 --> 50:14.100 And so that can be induced as well, or you can choose to attack in the times that you know they're most likely to be in a state like that. 50:14.340 --> 50:24.840 Response fatigue is the term that we use to describe when an alarm has too many false alarms and security decides they're going to stop responding to it. 50:24.840 --> 50:29.420 It's probably just a raccoon climbing the fence or bumping up against the fence or whatever. 50:29.480 --> 50:31.660 Kind of like the boy who cried wolf. 50:31.660 --> 50:39.160 So by setting off one alarm many, many times, making security think it's a false alarm, you can cause them to stop responding to that. 50:39.480 --> 50:41.960 They might have higher priority calls that come along. 50:42.020 --> 50:46.360 So you can set off more critical alarms than where you actually want to go. 50:46.360 --> 50:54.880 Security is going to go to that higher priority location and you now have a lack of response for where you are setting off whatever alarms you want to. 50:54.960 --> 50:57.280 They're often just plain old slow. 50:57.280 --> 51:13.000 So if there's not on-site security, if it's either an off-site security service or police that are called, they can take upwards of 30 minutes, maybe more, to get to the site and actually do a sweep and see if anything is amiss there. 51:13.020 --> 51:15.060 That is way too long. 51:15.060 --> 51:20.000 The vast majority of criminals are in and out well within that period of time. 51:20.080 --> 51:26.220 So just being fast enough that you outrun the response is usually sufficient as well. 51:26.220 --> 51:35.780 In terms of dealing with the response in an ethical hacking situation, so most commonly we see this with physical pen testing, there are a number of considerations to keep in mind. 51:35.960 --> 51:42.620 We don't want to diminish the ability of the facility to respond to a real threat that could do real damage. 51:42.620 --> 51:52.420 So that could happen both if we disable alarms, but also if we cause security to, say, have response fatigue on a particular alarm. 51:52.420 --> 51:56.120 Or if we cause them to be one place where there's a real incident and another. 51:56.120 --> 51:57.860 So that's something to consider. 51:57.940 --> 52:10.080 And we also don't want them to, especially if it's the police, to have responding to us as ethical hackers at the expense of other potential calls. 52:10.080 --> 52:23.860 So fairly famously now within this community is the Iowa courthouse pen test case, where two individuals were hired to penetration test a courthouse and they ended up getting arrested and charged as a result of it. 52:23.860 --> 52:27.740 A lot of people made a lot of mistakes in that particular case. 52:27.740 --> 52:47.520 But one mistake that, in my humble opinion, the red team made is it was irresponsible of them to have those police officers called to the site without prior notice to the force at the possible expense of other higher priority calls. 52:47.520 --> 52:57.000 Someone could possibly have died as a result of that if there had been a higher priority life or death call that was averted as a result of responding to this. 52:57.000 --> 53:05.960 So that is a number of considerations for attacking the response and for dealing with any of these alarm situations. 53:06.060 --> 53:16.980 We want to make sure that we do it responsibly and in a way that does no harm or does no unreasonable harm as determined by the client and external stakeholders. 53:17.680 --> 53:21.480 So I encourage you to try it out. 53:21.480 --> 53:28.580 We've released a couple of little games that let you practice these aspects that we've talked about throughout this talk. 53:28.580 --> 53:32.700 It has been a lot, so feel free to ask me questions. 53:32.700 --> 53:41.680 Feel free to give suggestions for something that you'd like to see at a future Bypass Village that you can practice hands-on, hopefully in person at DEF CON 29. 53:41.680 --> 53:47.460 But for now, you can practice rewiring alarms and using magnets to disable grid switches. 53:47.580 --> 53:51.180 And with that, I would be happy to take any questions that you might have.