Barcode Hacking Process

Posted April 12th, 2010 by

This is something I’ve been working on in my spare brain cycles:  building a process for barcode hacking.

Limitations with barcode hacking:

  • Feedback: is hard to get and depends on the scanner and the scanner app.  In other words, you really need access to a working setup to test any kind of techniques.  This isn’t web-based SQLi where you can compare the output against other results, you have to look “inside the guts” to see if a change happened.
  • Reflections and Noise: Laser-based scanners have problems with reflection on phone screens.  This *almost* limits you to printed barcodes and reduces some of the interactivity.
  • UPC: This symbology sucks for barcode hacking because you’re limited to 12 digits, no letters are supported.

Kernels of nummieness:

  • Most modern barcodes are attached via USB and are recognized as a keyboard.
  • Read the previous sentence again.  =)  You know what to do here.
  • The USPS uses DataMatrix barcodes for postage.  These include command characters that “freak out” anything I read them on.  This has much potential, now if I can figure out how to harness this for the powers of mischief.
  • I have a Symbol 2D barcode reader, you can buy them on eBay for ~$120.

The process should run something like this:

  • Configuration injection: given the make and model of the scanner, turn on all available symbologies to increase the reader attack surfaces. These command sets are available from the manufacturer and there is a wealth of untapped firmware vulns in them.
  • Discovery test: to determine which symbologies are supported by the barcode scanner.  The goal is to get something that supports the full ASCII set.  Code 128 (1D), PDF-417, QR, Aztec, and DataMatrix are your friends here.  For discovery, you can use “all 1’s” or something along those lines.
  • Command injection: attempt to pass OS commands to the reader application and download and install a payload onto the OS via browser, ftp, etc or to gain a shell on the box.
  • Application escape: Attempt to escape out of the application and into the OS.  Then it’s just a simple matter of regular exploits *or* if you’re lucky, you’re already admin.  At least try a ctrl-alt-del and see what happens.
  • SQL injection: this you know, string concatenation that’s passed to the database.  The problem is that depending on the system, you might not get feedback so blind SQLi is harder.  “‘ or 1=1;–” probably won’t work because there isn’t really a login or when you’re scanning barcodes you’re already past that point.  I think the goal here should be command execution: add users, exec OS commands, and turn on additional services.
  • Malformed barcode: as a last resort, try fuzzing with non-standards-compliant barcodes to get either the scanner or the application to barf.

BTW, all the kids with their barcodes that say “‘ or 1=1;–” crack me up because they’re being barcode skiddies and don’t understand how barcodes are really used.  =)

SQLi Test

SQL Injection Bogus Example by ME!  Only you can stop the stupidity.



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QR Code Temporary Tattoos Howto

Posted February 10th, 2010 by

So it started with an idea.  How cool would it be to get everybody to install a QR code reader and read temporary tattoos off each other?  Anyway, at Shmoocon I walked around with a bag of QR temporary tattoos much to the delight and chagrin of the hackers assembled therein.

The howto:
#1 Get a barcode generator. I use zint, it’s my favorite tool for generation.  For those of you on Ubuntu or Debian, I have packages built for you.  And give the zint guys some money while you’re at it, they use the funds to buy standards and make zint work with every symbology known to mankind.

#2 Get a layout program. I use Inkscape.  Key here is that it has to be able to import .svg files and be able to flip images horizontally.

#3 Get printable temporary tattoo paper. It’s not really cheap, but I found kits on tattoofun.com.  The kit consists of waterslide temporary tattoo paper, adhesive sheets, and an instruction sheet.

#4 Make .svg Barcodes! I load up zint and toss some text at it, then use the QR symbology.  Some examples:

  • sms:7035551234 body:Greetz from teh Internetz
  • MATMSG: TO:shredder@guerilla-ciso.com; SUB:Test; BODY:This is a test. Please reply if received.;;
  • MECARD:N:Wizzleteague, Stinky;ADR:1234 Main St, Arlington, VA 22202;TEL:+17035551234;EMAIL:shredder@guerilla-ciso.com;;
  • Hi, I’m Quine. I haz a RAGE! https://twitter.com/quine
  • I went to Shmoo and all I got was the flu
  • BTW, if you want to pay me to make QR tattoos for promotion events, drop me an email.

Zint Main Screen

#4.5 Add in QR error correction. The more error correction you use, the more data in the barcode so the smaller the blocks are.  However, some error correction compensates for distortion and glare.  IIUC, Zint automagically adds in 20% error correction.  I’m not sure what the magic number here is because it depends on the size of the printed barcodes.

Zint Error Correction

#5 Export barcode from zint. SVG is awesome to save as because you can scale the barcodes up as much as you want and they won’t get all pixelated-looking.  You can grab a ton of the barcodes I made here.

Save as SVG

#6 Import barcode into inkscape.  File=>Import then select the .svg file you want.  Since the barcodes are svg, you can scale them awesomely.  For mine, I set up guidelines so I could lay out rows proportionately.  Be sure to lock the object proportions or you’ll get hideously warped QR monstrosities that nothing can read.  You can grab my sheet of barcodes here.

Lock Aspect Ratio in Inkscape

#7 Make “The Big Flip” and print.  Inkscape-specific: Edit=>Select All   followed by   Object=>Flip Horizontal.  Then print the page on the glossy side of the slide water paper.

#8 Add the sticky.  It’s a bit like laminating a map only the adhesive is way more forgiving.  Poke some pin-holes in the adhesive sheet and smooth out all the bubbles.

#9 Cut, peel, stick, wet, pull, read, lol.  You can get a reader here, but the important bits: iTunes Store: Barcodes.  Android: Barcode Scanner.

Lessons Learned:

Laser barcode scanners don’t work because the film is reflective.  Photo-based barcode scanners (ie, most mobile scanners) work pretty well.

You have to make the barcodes bigger than I did.  Mine were .75x.75 inches and due to the glare on the paper and some distortion due to putting them on skin, they were hard to read.  I think maybe 2×2 inches are optimum.

Hackers don’t like informational urls in their tattoos: “I got an add for ZXing, this sucks”.  I think random goofy phrases and skin pwnage would work better than informational urls.

Some people (Quine) weren’t happy with a grab-bag random url and needed their own custom witty saying.  I felt the rage, it has now been fixed.

You can’t read the barcodes until they’re on the skin because of the horizontal flip.  Before you do the flip, print out the barcodes on regular paper.  You can read these easily enough.  Then flip the finished barcode sheet over after you’ve printed it and you can match up the barcode with the non-flipped sheet.  Even better if you use your computer monitor as a lightbox.

QR Temporary Tattoo



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Hack Disaster Relief

Posted January 25th, 2010 by

I’m curtailing my blog for a couple of weeks.  I’m busy helping out with Haiti.

I spent last Saturday at CrisisCamp DC.  It’s a barcamp-style hackathon to build applications to help relief workers in Haiti.  Think long-range wifi routers to network the country where the infrastructure is destroyed.  Think a website for quake survivors to tell their story.  Think a Craiglist for relief workers where somebody with an oxygen generator and  somebody with a power supply can get together and make something that helps both of them.  Think all of these created in an 8-hour development stint.

Yes, security folks, you can help.  Not only that, but you have the technical skills to get web apps stuff done and the project management experience to lay out what it is that needs to be done.

We’re holding another CrisisCamp in DC this Saturday the 30th.

Go to crisiscommons.org and look for a project that interests you or a local camp.

Here, let Andy Carvin break it all down “Big Bird Style”:

Movie by @Digiphile, Alex Howard from SearchCompliance.com.  Hopefully I didn’t just “out” him.  =)



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20 Critical Security Controls: What They Did Right and What They Did Wrong

Posted January 21st, 2010 by

Part 1

Part 2

Takeaways from the 20 CSC and what they do right (hey, it’s not all bad):

You have to prioritize. On a system basis, there are maybe 50-60 800-53 controls (out of a number just shy of 200) that need to be built 100% correctly and working every single time.  The rest (I know, I’m putting on my heretic hat here) can lapse from time to time.  For example, if I don’t have good event monitoring, my incident response team doesn’t have much work because I don’t know if I’m pwned or not.  What 20 CSC does is try to reduce that set of stuff that I should be concerned about into a set of controls that are technical, tactical, and track to classes taught by SANS vulnerability-based .

Common controls are more important than ever. They help you scope the smaller systems.  In fact, roughly half of the 20 CSC apply to the modern Enterprise and should be absorbed there, meaning that for systems not owning infrastructure, we only have 10 or so controls that I have to worry a bunch about, and 10 that I just need to be aware of what’s provided by my CISO.

Give examples. I’ll even go as far as to say this:  it should be a capital offense to release a catalog of controls without a reference implementation for both an Enterprise/GSS and a smaller IT system/Major Application inside of it.  20 CSC stops maybe one step short of that, but it’s pretty close in some controls to what I want if they were structured differently.

Security Management v/s IT Management. IT asset inventory, configuration management, change control:  these are IT management activities that somehow get pushed onto the security team because we are more serious about them than the people who should care.  I think 20 CSC does an OK job of just picking out the pieces that apply to security people instead of the “full meal deal” that ITIL and its ilk bring.

Control Key photo by .faramarz.

Now for what they did wrong:

It’s Still Not a Consensus, Dammit! That is, it’s a couple of smart people making a standard in a vacuum and detached from the folks who will have to live by the work that they do.  Seriously, ask around inside the agencies:  who admits to helping develop 20 CSC aside from “yeah, we looked at it briefly”?  And I’m not talking about the list that SANS claims, that’s stripped from the bios of the handful of people who did work on 20 CSC.  Sadly, this is the quick path to fail, it’s like building an IT system without asking the users what they need to get their job done on a daily basis.  Guys, we should know better than this.

It’s Still Not a Standard. It’s still written as guidance–more anecdote than hard requirements.  This isn’t something I can put into a contract and have my contractors execute without modifying it heavily.  It’s also not official, something I’ve already touched on before, which means that it’s not mandatory.  If you want to make this a standard, you need to turn it into ~50 controls each written as a “contracting shall”.  More to come on this in the future.

It Has Horrible Metrics. And I’m talking really horrible…it’s like the goatse of security metrics (NSFW link, even though it’s wikipedia).  Why?  Because they’re time-based for controls that are not time-based.  Metrics need to be a way to evaluate that the control works, not the indirect effects of the control.  Of course, metrics are just a number, but at the end of whatever assessment, my auditor/IG/GAO/$foo has to come up with some way to rank the work that I’ve done as a security officer.  If 20 CSC is the vehicle for the audit and the metrics are hosed, it doesn’t matter what I can do to provide real security, the perception from my management is that I don’t know what I’m doing.



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20 Critical Security Controls: Control-by-Control

Posted January 20th, 2010 by

OK, now for the control-by-control analysis of the 20 Critical Security Controls.  This is part 2.  Look here for the first installmentRead part 3 here.

Critical Control 1: Inventory of Authorized and Unauthorized Devices. This is good: get an automated tool to do IT asset discovery.  Actually, you can combine this with Controls 2, 3, 4, 11, and 14 with some of the data center automation software–you know the usual suspects, just ask your ops folks how you get in on their tools.  This control suffers from scope problems because it doesn’t translate down to the smaller-system scale:  if I have a dozen servers in an application server farm inside of a datacenter, I’ll usually know if anybody adds something.  The metric here (detect all new devices in 24 hours) “blows goats” because you don’t know if you’re detecting everything.  A better test is for the auditor to do their own discovery scans and compare it to the list in the permanent discovery tool–that would be validation that the existing toolset does work–with a viable metric of “percentage of devices detected on the network”.  The 24 hour metric is more like a functional requirement for an asset discovery tool.  And as far as the isolation of unmanaged assets, I think it’s a great idea and the way things should be, except for the fact that you just gave us an audit requirement to implement NAC.

Critical Control 2: Inventory of Authorized and Unauthorized Software. Sounds like the precursor to whitelisting.  I think this is more apropos to the Enterprise unless your system is the end-user computing environment (laptops, desktops).  Yes, this control will help with stuff in a datacenter to detect when something’s been pwned but the real value is out at the endpoints.  So yes, not happy with the scope of this control.  The metric here is as bad as for Control 1 and I’m still not happy with it.  Besides, if you allow unauthorized software to be on an IT device for up to 24 hours, odds are you just got pwned.  The goal here should be to respond to detected unauthorized software within 24 hours.

Critical Control 3: Secure Configurations for Hardware and Software on Laptops, Workstations, and Servers. This is actually a good idea, provided that you give me a tool to apply the settings automagically because manual configuration sucks.  I think it’s about a dozen different controls all wrapped into one, it’s just trying to do too much in one little control.  The time-based metric for this control is really bad, it’s like watching a train wreck.  But hey, I’ll offer up my own: percentage of IT assets conforming to the designated configuration.  It’s hinted at in the implementation guide, make it officially the metric and this might be a control I can support.

Critical Control 4: Secure Configurations for Network Devices such as Firewalls, Routers, and Switches. This is basically Control 3 for network devices.  The comments there also apply here.

Critical Control 5: Boundary Defense. This control is too much stuff crammed into one space.  As a result, it’s not concise enough to be implemented–it’s all over the map.  In fact, I’ll go as far as to say that this isn’t really one control, it’s a control theme with a ton of controls inside of it.  The “audit requirements” here are going to utterly kill me as a security manager because there is so much of a disparity between the control and the actual controls therein.

Critical Control 6: Maintenance, Monitoring, and Analysis of Audit Logs. Some of this control should be part of Controls 3 and 4 because, let’s be honest here, you’re setting up logging on devices the way that the hardening guide says you should.  The part that’s needed in this control is aggregation of logs and review of logs–get them off all the endpoints and into a centralized log management solution.  This is mentioned as the last “advanced” implementation technique but if you’re operating a modern Enterprise, I don’t see how you can get the rest of the implementation done without some kind of SIEM piece.   I just don’t get the metric here, again with the 24 hours.  How about “percentage of devices reporting into the SIEM”?  Yeah, that’s the easy money here.  The testing of this control makes me do a facepalm:  “At a minimum the following devices must be tested: two routers, two firewalls, two switches, ten servers, and ten client systems.”  OK, we’ve got a LAN/WAN with 15000 endpoints and that’s all we’re going to test?

Critical Control 7: Application Software Security. You keep using those words, I do not think they mean what you think they mean.  Application security is a whole different world and 20 CSC doesn’t even begin to scratch the surface of it.  Oh, but guess what?  It’s a tie-in to the 25 Most Dangerous Programming Errors which is about all this control is:  a pointer to a different project.  The metric here is very weak because it’s not tied back to the actual control.

Critical Control 8: Controlled Use of Administrative Privileges. This should be part of Controls 3 and 4, along with something about getting an Identity and Access Management system so that you have one ID repository.  I know this is a shocker to you, but the metric here sucks.

Critical Control 9: Controlled Access Based on Need to Know. This is a great idea, but as a control it’s too broad to achieve, which is why the 20 CSC were created in the first place.  What do we really want here?  Network share ACLs are mentioned, which is a control in itself, but the rest of this is hazy and leaves much room for interpretation.  Cue “audit requirements” and the part where Rybolov says “If it’s this hazy, it’s not really a standard, it’s a guideline that I shouldn’t be audited against.

Critical Control 10: Continuous Vulnerability Assessment and Remediation. All-in-all, not too bad.  I would suggest “Average time to resolve scan findings” here as a metric or even something as “hoakey” as the FoundScan metric just to gauge overall trends.

Arm Control photo by Crotchsplay.

Critical Control 11: Account Monitoring and Control. Haven’t we seen this before?  Yep, this should be incorporated into Controls 8, 3, and 4.  However, periodic account reviews are awesome if you have the patience to do it.

Critical Control 12: Malware Defenses. OK, this isn’t too bad.  Once again, the metric sucks, but I do like some of the testing steps.  The way I would test this is to compare our system inventory with my total list of devices.  A simple diff later, we have a list of unmanaged devices.

Critical Control 13: Limitation and Control of Network Ports, Protocols, and Services. Host firewalls was not what I thought of… I’m thinking more like firewalls and network segmentation where you have to get change control approval to add a firewall rule.  As far as the host setup, this should be part of Control 3.

Critical Control 14: Wireless Device Control. Not bad, but this should be dumped into a technical standard that you use like a hardening guide.  Metric here still sucks, but I don’t really need to say this again… oh wait, I just did.

Critical Control 15: Data Loss Prevention. Puh-lease.  I’ll be the first to admit, I’m a big believer in DLP done right, and that it’s an awesome tool to solve some of the unique .  But I don’t think that the market is mature enough to add it into your catalog of controls.  Also this will fall flat on its face if your system is just a web application cluster:  DLP addresses the endpoints (desktops, laptops, mobiles) and the outbound gateways (email, web, etc).  The problem with this control is that if you don’t buy and implement a full DLP solution (cue Rich Mogull and his DLP guide), there isn’t anything else that has a similar capability.  This is one of those controls where the 800-53 mapping gets really creative–Good Ship Lollipop Creative because we’re tapdancing around the issue that DLP-type solutions aren’t specifically required in 800-53.

These controls don’t have automated ways to implement and test them:

Critical Control 16: Secure Network Engineering. This control is a steaming crater.  It’s very much a guideline instead of an auditable standard.

Critical Control 17: Penetration Tests and Red Team Exercises. Not bad.  Still too easy to shop around for the bargain-basement penetration test team.  But yeah, pretty good overall.

Critical Control 18: Incident Response Capability. Good control.  Hard to test/audit except to look at after-incident reports.

Critical Control 19: Data Recovery Capability. Not bad here.  Not real COOP/DR/ITCP but about on par with typical controls frameworks.

Critical Control 20: Security Skills Assessment and Appropriate Training to Fill Gaps. Good idea.  Hard to implement without something like 8570.10 to give you a matrix by job position.  You want to change the world here, give your own mapping in the control.



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Opportunity Costs and the 20 Critical Security Controls

Posted January 13th, 2010 by

This is a multi-post series.  You are at post 1.  Read post 2 hereRead Post 3 here.

This post begins with me.  For the past hour or so I’ve been working on a control-by-control objective analysis of SANS 20 Critical Security Controls.  This is a blog post I’ve had sitting “in the hopper” for 9 months or so.  And to be honest, I see some good things in the 20 CSC literature.  I think that, from a holistic perspective, the 20 CSC is an attempt at creating a prioritization of this huge list of stuff that I have to do as an information security officer–something that’s really needed.  I go into 20 CSC with a very open mind.

Then I start reading the individual controls.  I’m a big believer in Bottom-Line-Up-Front, so let me get my opinion out there now: 20 Critical Security Controls is crap.  I’m sorry John G and Eric C.  Not only is 20 CSC bad from a perspective of controls, metrics, and auditing tests, but if it’s implemented across the Government, it will be the downfall of security programs.  I really believe this.

Now on to the rationale….

Opportunity Costs. I can’t get that phrase out of my head.  And I’m not talking money just yet–I’m talking time.  See, I’m an IT security guy working for a contractor supporting a Government agency–just like 75% of the people out there.  I have a whole bunch of things to do–both in the NIST guidelines and organizational policy.  If you add anything else to the stack without taking anything away,  all you’ve done is to dilute my efforts.  And that’s why I can’t support 20 CSC–they’re an unofficial standard that does not achieve its stated primary goal of reducing the amount of work that I have to do.  I know they wanted to create a parallel standard focusing on technical controls but you have to have one official standard because if it’s not official, I don’t have to do it and it’s not really a standard anymore, it’s it?

Scoping Problems. We really have 2 tiers inside of an agency that we need to look at: the Enterprise and the various components that depend on the Enterprise.  Let’s call them… general support systems and major applications.  Now the problem here is that when you make a catalog of controls, some controls are more applicable to one tier than the other.  With 20 CSC, you run the classic blunder of trying to reinvent the wheel for every small system that comes along.

Threat Capabilities != Controls. And this is maybe the secret why compliance doesn’t work like we think it will.  In a nice theoretical world, it’s a threat-vulnerability-countermeasure coupling and the catalog of controls accounts for all likely threats and vulnerabilities.  Well, it doesn’t work that way:  it’s not a 1-to-1 ratio.  Typical security management frameworks start from a regulatory perspective and work their way down to technical details while what we really want to do is to build controls based on the countermeasures that we need.  So yeah, 20 CSC has the right idea here, the problem is that it’s a set of controls created by people who don’t believe in controls–the authors have the threat and vulnerability piece down and some of the countermeasures but they don’t understand how to translate that into controls to give to implementers and their auditors.  The 20 CSC guys are smart, don’t get me wrong, but I can’t help but get the feeling that they don’t understand how the “rest of the world” is getting their job done out there in the Enterprise.

The Mapping is Weak. There is a traceability matrix in the 20 CSC to map each control back to NIST controls.  It’s really bad, mostly because the context of 800-53 controls doesn’t extend into 20 CSC.  I have serious heartburn with how this is presented inside the agencies because we’re not really doing audits using the 20 CSC, we’re using the mapping of NIST controls with a weird subtext and it’s a “voluntary assessment” not an audit.

Guidelines?!?!?! This is basic stuff.  If it’s something you audit against, it *HAS* to be a standard.  Guidelines are recommendations and can add in more technique and education.  Standards are like hard requirements, they only work if they’re narrowly-scoped, achievable, and testable.  This isn’t specific to 20 CSC, the NIST Risk Management Framework (intended to be a set of guidelines also) suffers from this problem, too.  However, if your intent is to design a technical security and auditing standard, you need to write it like a standard.  While I’m up on a soapbox, for the love of $Diety, quit calling security controls “requirements”.

Auditor Limitations. Let’s face it, how do I get an auditor to add an unmanaged device to the network and know if we’ve detected it or not.  This is a classic mistake in the controls world:  assuming that we have enough people with the correct skillsets who can conduct intrusive technical tests without the collusion of my IT staff.

And the real reason why I dislike the 20 Critical Security Controls:

Introduction of “Audit Requirements”. One of the chief criticisms of the NIST Risk Management Framework is that the controls are not specific enough.  20 CSC falls into this trap of nonspecificity (Controls 7, 8, 9, and 15, I’m talking to you) and is not official guidance–a combination that means that my auditor has just added requirements to my workload simply because of how they interpret the control.  This is very dangerous and why I believe 20 CSC will be the end of IT security as we know it.

In future posts (I had to break this into multiple segments):

  • Control-by-control analysis
  • What 20 CSC got right (Hey, some of it is good, just not for the reasons that it’s supposed to be good)

SA-2 “Guideline” photo by cliff1066™.



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