FORKEVER

Are you tired of countless restarts when studying binary exploitation?

Are you sick of manually inspecting the same memory address over and over again?

Do you have enough of writing the same data to that babyheap challenge's STDIN just to call malloc?

Well then Forkever might be just the right tool for you!

Given a binary that you want to exploit, Forkever is a debugger that lets you

fork the debugged at any given point in time to create "checkpoints"
call functions at any time (e.g. "malloc 10" when training heap exploitation)
view and change the memory in real-time using a hexeditor

Forkever was developed with heap exploitation in mind, and has already assisted students of the BX course at TUM. Further, it helped with solving a TSG-CTF challenge.

small demo

video demo @ vimeo

Launch Forkever:

./forkever echo "hello" "bye"

Randomisation of addresses is disabled by default, you can reenable it with "-rand"

To save time, you can also pass a file with commands that should be run instantly: "-init path/to/file"

essential commands:

b <address>  -  set a breakpoint
c  -  continue execution
fork <name>  -  fork to create a backup of the process, name is optional
tree  -  print process tree
switch <name|pid|"up">  -  switch to another process

call binary:function_name arg0 arg1 arg2  -  call the indicated function

hyx <segment| >  -  view the indicated segment (default: view heap)

In the application, enter "?" for a list of commands To learn more about the hyx command for example, type "?hyx"

You can adjust behavior further by fiddling in Constants.py, but be careful! ;)

install

pip install pwntools
git clone https://github.com/haxkor/forkever
chmod +x forkever/forkever.py
gcc -o forkever/launcher/launcher -g -no-pie forkever/launcher/launcher.c

git clone https://github.com/haxkor/hyx4forkever
gcc -o hyx4forkever/hyx -pthread hyx4forkever/*.c

Forkever makes use of (a slightly modified) python-ptrace. The Author of this library recommends to install the binding of ptrace "for faster debug and to avoid ctypes", although it is not necessary.

cd forkever/installCptrace
python3 setup_cptrace.py

known problems

Forkever does not immediately launch the program you provided. Instead, it starts up the "launcher" and starts tracing that launcher. Once attached, the launcher will start the provided process. It can happen that Forkever will fail to attach to the process and exit. The launcher will then be stuck in an infinite loop and eat your CPU.

In this case, find out the PID with ps aux | grep launcher and kill the process yourself.

B U G S ?

~~Incase~~ Once you find them, please open up an issue on Github

haxkor / forkever