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Setting up a Windows 7 Kernel Development Environment

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If you are writing some Ring0 (or privileged mode code), say something like device drivers in Windows you’d probably be better served with a separate development machine and a deployment machine. This helps you to write poor code and still not lose hair because your development machine blue screens! 🙂

My setup was using a Windows 8.1 development machine and a Hyper-V based Windows 7 machine for debugging. You will need to execute different tasks on the “guest” (Hyper-V based Windows 7 virtual machine) and some other tasks on the development machine.  I followed many of the things from the MSDN blog post here

On your guest machine you would want to setup a named pipe and setup debug settings. To do that this is what you need to do:

Setup a virtual com port in the Hyper-V Settings (File -> Settings) , this port will be used to communicate from the host machine to the guest to communicate the Kernel debugging commands.
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Now make sure that your target guest machine is configured to “listen” those commands.  Inside the guest VM, start a command shell (cmd.exe -> Run as Administrator).

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Configure the bcdedit commands so that the machine can now be debugged.  Right after the 2nd command, reboot your Virtual Machine.

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With the VM now configured to listen the debug commands via the COM1 port, and the debug mode on in the bootup settings, now start the WinDbg x64 on the host (using “Run as administrator”; you need administrative privileges for communication via Serial port).  In your kernel debugger on the host or the development machine (I’m assuming that these are both on the same physical hardware here).  Click on File -> Kernel Debug and you should see the following screen in the WinDbg window:

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Hit Ctrl+Break or Debug -> Break and you will see something like this:

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Just remember that when you break in the debugger, your guest in Hyper-V should become “unresponsive”.  The only thing is that it is not really unresponsive, its just being debugged.  Just to make sure, that you have the symbols package that is quite useful for debugging run the following command:

!process 0 0

If you see something like the following screen show up:

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The following error means that the symbols are not defined.  Symbols help the debugger give more information about the commands that you are going to execute in the debugger.

**** NT ACTIVE PROCESS DUMP ****
NT symbols are incorrect, please fix symbols

To fix this, use the following commands:

kd> .sympath SRV*c:\symcache*http://msdl.microsoft.com/download/symbols
kd> .symfix
kd> .symfix c:\symcache
kd> !sym noisy
kd> .reload /o

Then again try the command: !process 0 0 and see if you get a good response.  A good response looks like the following:

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With this you should be good to go! Happy debugging and writing cool Ring0 code.

 

 

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System Information

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This has been a weird one, finding version information on the operating systems.
On Ubuntu, the following gets the version information
  cat /etc/issue
  cat /etc/lsb-release

On Linux, finding the kernel version
  uname -a
  cat /proc/version

On Windows, from Start-> Run -> cmd.exe
  winver
OR
  systeminfo

This is very simple but still there are a few times when memory fails and we’re not able to do the obvious.

To see the information about the hardware mapping :
  lshal

Finding your CPU Information
  cat /proc/cpuinfo

Finding memory information
  cat /proc/meminfo

Maximum number of SYN requests that the host will remember which did not receive an ACK from clients:
  cat /proc/sys/net/ipv4/tcp_max_syn_backlog

Finding data bus-size or bit-size i.e., whether my CPU is 32-bit or 64-bit:
  sudo lshw -C cpu | grep width

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Ratproxy on Cygwin

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I have used Michal Zalewski’s Ratproxy on Google code. I like it a lot. But I also like to have it on Windows. But it seems that the makefile that comes with ratproxy is not really compatible with cygwin.
If you have the gcc, make, openssl, openssl-dev packages installed on cygwin, all you need to do is remove the -Wno-pointer flag from the CFLAGS entry from the Makefile.
So my Makefile’s CFLAGS line looks like:

CFLAGS  = -Wall -O3 -D_GNU_SOURCE

I also replaced $(CC) with gcc just because I felt like it. 🙂
Compile it with make command.
Do not forget to dos2unix the ratproxy-report.sh otherwise you will get some errors with ‘\r’ and some other random stuff when you run the report generator shell scripts.
Run ratproxy as :
c:\tools\ratproxy>ratproxy.exe -p 8000 -v c:\testdir -w ratlog -d example.com -extifscfjmXCk
Once you have the log to generate a nice looking pretty report:
bash$ ./ratproxy-report.sh ratlog >reportname.html

Update 06/20/2012:
If you get the error shown below:
ratproxy.c: In function `listen_loop':
ratproxy.c:1635:5: error: incompatible type for argument 2 of `waitpid'
/usr/include/sys/wait.h:43:7: note: expected `__wait_status_ptr_t' but argument
is of type `unsigned int *'
Makefile:30: recipe for target `ratproxy' failed
make: *** [ratproxy] Error 1

Do the following:
1. Go to line # 1635 and change the line to while (waitpid(-1,(int*)&x,WNOHANG) > 0);
2. Goto the command line and type

make

You should be able to compile ratproxy.

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Machine Learning Security in the age of Supply Chain Attacks

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As can be seen from the recent “xz attack” discovery that there nation states have realized that this is likely the “best” vector to impact large-scale systems in big organizations. With the cloud computing providers being the “source of computing” for most large corporations today, we should anticipate that a larger portion of the attacks will fall into this category. Also, just like “sleeper cells” in traditional espionage, such “sleepers” may exist in numerous OSS projects. Does that mean we should stop using open source – hell no. All that means is we just need to be careful. Can we detect these attacks? It’s tough to detect but yes we can detect them by good ol’ school, telemetry and observability.

But that’s not what this blog post is about. I think the most interesting bit from the xz attack for me was that the libraries that get harder to debug and decode are much juicier targets. How does that matter? The ML libraries that are super popular like pytorch and tensorflow and others are quite hard to compile out of bound from scratch. Such libraries can have interesting attack vectors which allow nice pickle compromises. I say “nice” because the family of insecure deserialization has existed in CWE since 2006! It’s older than many other issues and will continue to exist.

My only hope is that maintainers of core ML projects such as PyTorch, Tensorflow, keras and others start showing a slightly higher level of paranoia and build reproducibility so the supply chain attacks can be avoided on such harder to debug libraries.

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Packet Forgery

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In the past few days, coincidentally I’ve been thrown into situations where packet forgery has been required. So I thought it’ll be a great moment to enumerate some good options that network or security professionals have. The basis for most of these tools lies in libnet and libpcap which are some of the most wonderfully functional libraries out there.

  • Packetforge-ng – On the wireless side this utility allows you to capture wireless packets and create legitimate packets with a pre-determined payload that can then be replayed using tools such as aireplay-ng
  • Scapy – This is a python based tool and can be extended to write custom Python scripts to custom create packets. This library has great functions to form packets layer-by-layer and other functions such as fuzz() that allow fuzzing of packets out of the box. The greatest utility comes by the use of python language to create custom tools. Imagine creating custom thick clients just by using simple python scripts. The capabilities with this library are endless!
  • TCPReplay – Just convert your pcaps into traffic by replaying them. An excellent tool but be careful if you’ve sniffed some ARP packets. You could end up corrupting the ARP table entries (unless that’s exactly what your intentions is 😉
  • file2air – An excellent tool by Joshua Wright to replay packet contents.
  • Packit – A really easy to use and functional linux based packet injection tool.
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The case of an ID theft scam

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An interesting incident happened this past week to a friend – he had his identity stolen. More specifically, someone got a hold of his social security number (SSN), his date of birth (apparently) and his address. What the scammers or their “mules” (a term used to describe criminals who act on behalf of the actual criminal at their behest) did was that they went to the bank and requested to wire a huge sum of money to an account. The neat trick they played was before actually going to the bank they called the Verizon helpdesk and suspended my friend’s phone service. When they reached the bank and showed the bank agent the ID (some sort of a non-standard / fake ID) and gave the SSN to the bank agent, he/she grew suspicious and tried to contact my friend. However, due to Verizon suspending his phone service, the bank agent couldn’t get a hold of my friend. Luckily, the bank agent also sent my friend an email to which he responded promptly. The culprits were arrested and the investigation is still on.
What was quite interesting was, the modus operandi where the criminals know that banks rely on calling the customers if they suspect fraud and they had this covered. Quite intelligent.
So, you know what you need to do if your phone suddenly stops working – check if ID thieves have had a run on you, change all your passwords including email, change your credit card accounts and bank accounts and PINs and place a hold on your credit history with the credit reporting agencies such as Experian, Equifax and TransUnion.

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Projects…interjects!

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Come end of semester and the project deadlines start impending! The situation I am in is one of great thrill and rush! For the CS558L I’m doing this project in which I have to implement an automated worm fingerprinting mechanism but not only that combining it with ITrace I want to make Worm attacks and DDoS attacks a thing of past!
The scheme in plain English is to detect automatically if your network is being attacked by looking at the traffic and if so communicate this information to whoever you are forwarding this packet to! The ICMP messages that will be forwarded will carry information about who sent this traffic and other such information (including the signature of attack traffic). The receiver with all this information could gather the source of attacks. If all the routers followed this scheme then we will be able to reconstruct the entire path of the attack so the entry point of the attack could also be sealed….(hopefully leading to a Worm and DDoS attack-free internet)!!!
Really hopeful…aren’t I??? 😉
But again this technique has the same single flaw as the other techniques in that it needs co-operation between ISPs.
I am currently coding this scheme in the Linux Kernel 2.6.11.7 and this is my first tryst with linux kernel programming…let’s see what future holds for me!