`pwnlib.windbg` — Working with WinDbg

During exploit development, it is frequently useful to debug the target binary under WinDbg. This module provides a simple interface to do so under Windows.

Useful Functions

attach() - Attach to an existing process

Debugging Tips

The attach() and debug() functions will likely be your bread and butter for debugging.

Both allow you to provide a script to pass to WinDbg when it is started, so that it can automatically set your breakpoints.

Attaching to Processes

To attach to an existing process, just use attach(). You can pass a PID, a process name (including file extension), or a process.

Spawning New Processes

Attaching to processes with attach() is useful, but the state the process is in may vary. If you need to attach to a process very early, and debug it from the very first instruction (or even the start of main), you instead should use debug().

When you use debug(), the return value is a tube object that you interact with exactly like normal.

Tips and Troubleshooting

`NOPTRACE` magic argument

It’s quite cumbersom to comment and un-comment lines containing attach.

You can cause these lines to be a no-op by running your script with the NOPTRACE argument appended, or with PWNLIB_NOPTRACE=1 in the environment. (The name is borrowed from ptrace syscall on Linux.)

$ python exploit.py NOPTRACE
[+] Starting local process 'chall.exe': Done
[!] Skipping debug attach since context.noptrace==True
...

Member Documentation

pwnlib.windbg.attach(target, windbgscript=None, windbg_args=[]) → int[source]

Attach to a running process with WinDbg.

Parameters

target (int, str, process) – Process to attach to.
windbgscript (str, list) – WinDbg script to run after attaching.
windbg_args (list) – Additional arguments to pass to WinDbg.

Returns

int – PID of the WinDbg process.

Notes

The target argument is very robust, and can be any of the following:

int: PID of a process
str: Process name. The youngest process is selected.
process: Process to connect to

Examples

Attach to a process by PID

>>> pid = windbg.attach(1234) 

Attach to the youngest process by name

>>> pid = windbg.attach('cmd.exe') 

Attach a debugger to a process tube and automate interaction

>>> io = process('cmd') 
>>> pid = windbg.attach(io, windbgscript='''
... bp kernelbase!WriteFile
... g
... ''') 

pwnlib.windbg.binary() → str[source]

Returns the path to the WinDbg binary.

Returns: str – Path to the appropriate windbg binary to use.

pwnlib.windbg.debug(args, windbgscript=None, exe=None, env=None, creationflags=0) → tube[source]

Launch a process in suspended state, attach debugger and resume process.