IT Security Secret Weapon: Physical Control

Strong IT security is a losing proposition.   If you want to develop a system that’s connected to the internet that is unhackable, you’ve lost the game already.   There is no such thing.  If someone wants to hack you they will succeed.   The only thing you can do is inch your way up the ladder and eliminate the lowest hanging fruit.   The strategy becomes being faster than your friend rather than trying to outrun the bear.   Other than that get ready to be hacked.   Your goal should be to get hacked less frequently than your competitors, and when you’re hacked you want to be sure it’s an inconvenience rather than a business ending catastrophy.

Preventing the severity of the attack is where the tables turn.   You as an owner of your data, have an upper hand in restoring control. Just as you had no foolproof protection against getting hacked, your adversary faces the same problem if their goal is to wipe  your data or your business operation off the face of the earth.   They will not succeed if you don’t want them to.  Your secret weapon is physical control.  As long are you retain physical control over your data, you may lose many battles, but you will ultimately win the war.

When hackers penetrate a single system, they call that “owning the system”.   However, that is overstating their accomplishment a bit.   They should really claim that they “temporary control” the system.   Of course, that doesn’t have the same ring to it.   They don’t “own” anything if they can be locked out by you the owner.    Yes, they can do all kinds of damage while on the system.   Yes, they can cause down time.   Yes, it can be a huge disaster.   Yes, it sucks to be hacked.  But as long as you retain physical control over your system you’ll always have the upper hand in the long run.

Why physical control?   What makes physical control so special?  It’s because no matter what kind of games and silly wars happen at the OS or application level, you have a secret secret weapon that hackers don’t.   It’s a weapon that’s unstoppable.   It’s a weapon that makes all the games stop.   You have physical control.   Only you can unplug a network cable – they can never plug it back in.   Only you can shutdown a machine – they can never start it.  Only you can do a offline bare-metal restore and they can’t do a thing about it.   Only you can put your your offsite backups in your briefcase, they can hack all night and they are not going to touch those.

This is why public cloud computing is problematic.   Public cloud takes away the only truly effective weapon you had.   You have 0 physical control in public cloud.   You can’t unplug cables, you can’t carry away your backups in a briefcase,  and you can’t restore elsewhere.   You’re not the owner anymore.  With public cloud, you’ve outsourced the battle.  The battle is now between your cloud provider and the hacker.   Will the cloud fight as hard for you as you would fight for yourself?   Probably not.  In fact I guarantee it.   The cloud will point their finger at you and call it a day.

If you’re going to use the cloud, your physical infrastructure needs to be the root that controls it all.    Don’t think of a cloud as a way to “keep your stuff safe”, think of it as a pace where you temporarily place your stuff to get a specific job done.   It could be there one day, gone the next – just like a cloud.   You should always remain the physical owner of your data and of your key infrastructure.





Value of Personal Computing in the Cloud Era

I got my first computer when I was around 10 years old. It was a ZX80 clone with a whopping 64K of RAM. I had a game of pong on that came on a cassette tape and took 30 minutes to load. Sounds annoying now, but at the time, it was the most awesome thing ever. It was magic. As my programming skills improved and as I saw Moore’s law rip open previous computing limits, that sense of magic became internal and intimate. It changed from “wow, look at what that neat box can do”, to “wow, I’m wielding this magic at my fingertips”.   It’s not an accident that computer programmers and system admins are called wizards. When they place their fingers on a keyboard feels like wielding a magic wand. The possibilities feel endless. They are endless.

A personal computer is an intimate extension of our brains. It makes us think faster with powerful CPUs, have photographic memory with gigantic storage, analyze sort and distill information with smart algorithms, have telepathic powers through internet communication and it creates a playground for our imagination through virtual worlds and simulations. Personal computers are the vessel for electronic thoughts. Just as thoughts are personal and private, so is private computing. It’s a personal and private experience.

Cloud computing takes the closely held magic away from us and places it in the hands of a powerful corporation. If you are a magic user rather than magic wizard, this doesn’t seem like a big difference. After all you still reap the benefits, you still touch your precious keyboard and with a press of a button magic happens. The key difference is that with personal computers you own that magic – it’s personal. With cloud computing that magic happens at someone else’s bidding. The user is merely presented with the end result. It’s magic for rent.   It’s a satisfying illusion. When you use cloud computing, you’ve put away your wizard’s wand and substituted it for a fancy TV remote control. Often cloud computing magic appears more powerful than what you could ever hope to accomplish on your own. For that reason it’s tempting to put away your dusty old wand and to follow the rest of the herd away from that dried up patch of pasture you call “yours”, to a never-ending green field shared by all. Unlike personal computing, cloud computing is also easy, it doesn’t force you to learn and it doesn’t demand you to work. Most importantly doesn’t demand answers to any questions. The only thing is to open your mouth, chew and swallow that juicy green grass.

Does this mean cloud computing is always a bad idea? Certainly not. Personal computing is not about living in a cave as a hermit. It’s about defining limits. Personal computing is a question. What is yours and private? What is shared? What is off limits? What should always stay personal? What is the value of your privacy? What can you afford to let float into the cloud? What will you share? What will you keep secret? And when you are ready to head off to the never-ending green field shared by all, ask yourself: Who owns that field? Will it always be green and never-ending? Who makes the rules while I’m there? And most importantly, can I get best of both worlds? Can I visit the never ending green field for a few hours and return back to my own place at a moment’s notice? Or am I entering a one way corral? Can I keep my wand? Or do I have to trade-it-in for a remote control at the gate?

Draw a boundary; define your kingdom – no matter how big or small. Ask yourself, can I claim that territory my own the same way as I claim my mind my own?

Am I free? Will I remain free?

Undetectable Keylogger in 30 minutes

I noticed that all 60 out of 60 popular Windows anti-virus and anti-malware solutions do not catch the simplest keylogger.

For the test I created a windows application using the popular UserActivityHook.cs library.   It took me about 30 minutes of mostly copy and pasting.  I didn’t have to obfuscate the nature of my program nor did I have to pack it’s binary contents.    The program runs as plain user – it doesn’t need privilege escalation either.  In other words, it is very dangerous.   I scanned the executable through virustotal as well as few popular anti-virus and anti-malware programs on various workstations locally and they all passed the keylogger as 100% ok.

This doesn’t illustrate my hacking abilities (I used none).   What this does illustrate is the poor state of anti-malware and anti-virus tools at the moment.  No matter what the marketing materials tell you, the only protection these tools offer you is against specific white-listed instances of malware. For any other attack you’re on your own.


I couldn’t believe my eyes, either, so I decided to dig deeper.

Why was this so easy?

To understand that let’s dig into the various detection methods antivirus programs have at their disposal (thanks Wikipedia) and why each method fails

  • Signature-based detection: is the most common method. To identify viruses and other malware, the antivirus engine compares the contents of a file to its database of known malware signatures. Since this malware is new, there is nothing to compare to.   This is also another reason why I’m not posting the keylogger for everyone to download.   Days after I release it, it will get picked up by one of the many anti-malware teams and a signature will be made out of it in a hurry.   I don’t want to be tagged as distributing malware down the road.   This approach is mediocre, but it’s not good enough – definitely not as good as the various vendors would have you believe.   It’s trivial to bypass the anti-malware scan if you spend 30 minutes making your own.   Even if you copy and paste bunch of stuff together.  On the other hand if you’re using someone else’s tool it will get picked up as malware sooner or later.
  • Heuristic based detection: is generally used together with signature-based detection. It detects malware based on characteristics typically used in known malware code.   I was kind of rooting for the anti-malware programs to catch it based on heuristics,  if they can’t catch my test, how are they catching the keyloggers that others are trying to use against me?    Sadly none did.   This is most likely due to the fact that the Windows security architecture allows keylogging as a very routine function that is used by many legitimate applications.   In particular the keylogger depends on GetKeyboardState API call that’s used for many other benign reasons by other applications.   I still think if the anti-virus companies tried harder, they could catch this based on heuristics.  Currently they obviously don’t.
  • Behavioural-based detection: is similar to heuristic-based detection and used also in Intrusion Detection System. The main difference is that, instead of characteristics hardcoded in the malware code itself, it is based on the behavioural fingerprint of the malware at run-time. Clearly, this technique is able to detect (known or unknown) malware only after they have starting doing their malicious actions.    Once again anti-malware products didn’t live up to this promise.  They could have noticed the writes to disk milliseconds after each key press – they didn’t.   Then again, it is tricky.  There are lot of legitimate programs out there that do write to disk after key strokes and they aren’t key loggers.  
  • Data mining techniques: are one of the latest approach applied in malware detection.   Data mining and machine learning algorithms are used to try to classify the behaviour of a file (as either malicious or benign) given a series of file features, that are extracted from the file itself.    Data mining should have been a no-brainer for an anti-malware tool.    I was doing all sorts of suspicious stuff in my code and not hiding it one bit.   I guess we have to wait until this matures a bit, but given how miserably the other methods failed, I’m not holding my breath for that.

So….  this sucks.   How do you protect myself then?    Right now, you probably can’t.   Anti-malware companies have to step up and detect these kind of things.    Be skeptical, just because you see 57 green check marks on virus total, doesn’t mean it’s safe.   And no, don’t stop using your anti-virus, virustotal or whatever else you have.   Even if anti-virus is 90% effective.  That’s better than 0% without it.

ASP.NET dll download vulnerability


  1. Guess what the dll of the core application is called.  By default it will be called the same name as the ASP.NET project created by the programmer.   Other than taking a guess based on the name of the web site, often it’s possible to determine the name by browsing HTML source or by triggering errors.
  2. Download the main dll by requesting the following URL:
  3. Once you’ve got the .dll downloaded you can decompile it using ILSpy or your own favorite reversing tool.   If you’re lucky, you may find hardcoded passwords.  If not, you can now look for SQL and Linq injection opportunities that the source code is likely to reveal.


  • Most IIS installations restrict access to /bin/ folder by default, but I’ve noticed that for some reason, some don’t.   One way to block this attack is by adding a hidden segment “bin”.


  • I found at least one Linux system running Apache with Mono that was vulnerable.  Linux is not immune, if anything I’d say it’s more likely to allow this attack.

Asterisk – Seamless dialing of remote extension through DTMF

Problem Description:

There are two offices.  Office A runs Asterisk / FreePBX while office B runs a closed system with auto attendant.

The guys at office A would like to be able to dial office B extensions as if they were local.


Solution Overview:

Program the office A extensions in this way:

  1. Local extension picks up
  2. Remote office number is called
  3. When the remote office picks up
  4. DTMF key presses are sent to select the right extension
  5. Call is connected

Solution Details:

First I attempted to program this into freePBX through the GUI, but I wasn’t having any luck because the default macros were not letting me craft the dial command in such a way that it sends the key presses after the call is placed.   Although it would have been nice to have everything in the GUI, the FreePBX GUI method seems to be a dead end.  I ended up relying on good old /etc/asterisk/extensions_custom.conf configuration file, and I just created my own extensions there.

exten => 102,1,Dial(SIP/v-outbound/4031112222,30,rD(ww11))
exten => 103,1,Dial(SIP/v-outbound/4032223333,30,rD(ww12))

[ext-local] sets the right context so that these extensions are picked up as if they were local.  You could also put these into other contexts like [ivr-1] etc.

D tells the Dial command to send DTMF button presses after the remote end picks up

w tells the Dial command to wait 0.5 seconds


Speed and Latency from Calgary to the Internet

I’ve always been fascinated by the relationship between internet speed and latency.   I know that for a given a specific latency you can calculate the maximum speed of an internet connection:

TCP-Window-Size-in-bits / Latency-in-seconds = Bits-per-second-throughput

It’s described in more detail here

But will that hold up in real world tests?  I decided to measure it.  Here are the results:



To do this I did the following:

  •  Created a script that tested each of the ~3000 servers by wget’ing a large test image from each.   Ran this off of a 1 Gbs connection, on Centos 7 server with default window size.
  • Summarized the data by country
  • Uploaded to to make it pretty

Here are some interesting things that came out of this little experiment:

  • Countries in the same geographic region that have slower throughput are not running at their full potential.  Examples include: Guatemala, Brazil, Libya, Latvia, Lithuania, Iceland, Portugal, etc.    Take these results with a grain of salt, because some of these suffer from small sample size.  For example, I had to remove Japan from the data set because the only server Japan  was a unusually slow one.
  • Vast majority of the countries do run at their theoretical max throughput.   That means that most of the time, as long as you know your TCP window size, you can easily calculate the throughput with confidence.
  • You can roughly deduce route paths by looking at the map.  Take Iceland for example.  Even though it’s closer to Canada than Great Britain, the route clearly traverses through Great Britain, Ireland or Norway before heading to Iceland.

Unexpected results:

  • I got an impossible latency for Pakistan.  (47 milliseconds)  With that latency there is no way to even get to Europe, much less China.  The closest country with that kind of latency is Mexico.  I eliminated that from the data set as an anomaly.
  • I got impossible latency for Morocco.   (64 milliseconds).  Again, that’s way too quick.  I’m guessing both Morocco and Pakistan have been  mis-classified and are actually somewhere in the USA.

Remaining questions:

  • If you noticed, I haven’t said what my Centos 7 default TCP window size was.   That’s because I’m not really sure my self.  Working back from the real-life results, I’m sure the window size is approx 1,000 KB.  However, that doesn’t seem to match these parameters on my system: net.core.wmem_max = 212992 and net.ipv4.tcp_wmem = 4096 16384 3915616 … there must be some multiplication division factor involved.  Or maybe I’m looking at the wrong parameter altogether?

Am I a white hat or a black hat hacker?

Every time I hack or crack something, I face a tough ethical dilemma. I wonder, am I hurting people’s security and privacy by doing this? When I improve the code that is designed to simplify the cloning of RFID access cards, am I helping the society? Am I helping criminals break into buildings? When I write a tutorial that explains “how to hack in”, am I helping the society? Or am I helping the criminals send phishing spam?
To untangle this, let’s start with definitions. White hat hacker is defined as someone who improves security, while a black hat hacker is defined as someone who harms security. This isn’t very helpful. Whose security are we talking about? Is a hacker working for a government security organization considered white hat or black hat? After all, they are improving *their* organization’s security. Are our guys the white guys, while “the other” guys are black hat? And how do we define harm or benefit? Is a hacker who releases info about 0-day exploit causing harm, or benefit? It seems these definitions shift the ethics off to another level avoiding the deeper philosophical implications.

Here is a more useful definition:

  • White hat hacker: Hacker who shares their tools and knowledge in a public and open manner for the purpose of enabling everyone to gain privacy and control.
  • Black hat hacker: Hacker who secretively guards their tools and knowledge for the purpose of relinquishing privacy and control from others.

This definition allows us to ask us another interesting question. What would happen if majority of hackers were white hat? What would happen if majority of hackers were black hat?

Black Hat Majority:


Information security is in a very bleak state. Black hats have all kinds of back doors, and everyday users can only throw up their arms and say “privacy is dead”, “liberty is dead”, “I do not have control over my devices – others do”. This is a state we are in now.


White Hat Majority:


Information security is in a good state. Published exploit is a defensible exploit. Black hats still have the fringes to operate in. However, overall, every day users are fairly certain that they have the control over their systems and that they are not just puppets within a system controlled by others.

This makes it easy for me to say: I’m proud to be a white hat hacker.  I’m also proud to be on the right side of the race between the two sides.

I hope this makes others who have been on the sidelines, wondering what’s the right thing to do, jump right in.

Improved proxmark3 scanning of ioProx / Kantech fobs

I’ve been playing with my new proxmark3. It works great for HID cards, but ioProx code is still in its infancy. I made some improvements to it based on analysis by marshmellow:

  • Better accuracy: You no longer have to worry about centering your fob on the antenna or scan it repeatedly to get a “good” reading. Now you can just hold it in your fingers to scan. Before this update I was averaging 10 – 70% accuracy depending on how I held the fob. This version is pretty much 100% – I haven’t had a bad scan yet.
  • Correct decoding of human readable XSF number: Previous version had a bug that displayed the wrong unique code and the wrong facility IDs.


Download the binary firmware (including source code patch if you want to build it yourself) .

There is still more work to be done. For example, there appears to be CRC or checksum near the end – it’s still a mystery.

Quick and easy iptables based proxy

Today was a busy day dealing with power outage that affected 2100 businesses in downtown Calgary. Of course, couple of my clients were in the zone that went dark. I offered them to run their key infrastructure from my place for couple of days. Everything went great, except I have only 1 IP address on my connection. That’s not good when both clients want to come in on port 443. What to do?

Call up my ISP and order another IP? Nope: Takes too long, too expensive, I just need this temporarily. Also, ISP might mess it up and take me offline for a while.

Get VM with IPv4 IP and proxy the traffic over? Yes, but why go with something heavy handed like nginx?

I prefer this elegant solution brought to you by iptables:

# echo 1 >| /proc/sys/net/ipv4/ip_forward
# iptables -t nat -A PREROUTING -p tcp -d $IP_OF_VM --dport 443 -j DNAT --to $IP_WHERE_IM_FORWARDING_TO:8443
# iptables -t nat -A POSTROUTING -j MASQUERADE