Ropper

Overview

Ropper is a comprehensive binary analysis framework for finding Return-Oriented Programming (ROP), Jump-Oriented Programming (JOP), and Syscall-Oriented Programming (SOP) gadgets in compiled binaries. It facilitates exploit development, binary patching, and security research by identifying reusable code sequences that can be chained together to bypass protections like ASLR and DEP (Data Execution Prevention).

Installation

# Install via pip
pip install ropper

# Install with all dependencies
pip install ropper[all]

# From source (GitHub)
git clone https://github.com/sashs/Ropper
cd Ropper
python setup.py install

# Verify installation
ropper --version
which ropper

# Check dependencies
ropper --check-deps

Core Concepts

ROP (Return-Oriented Programming):

• Chains sequences ending with ret instructions
• Overwrites return addresses to execute gadget sequences
• Bypasses code execution restrictions

JOP (Jump-Oriented Programming):

• Uses jmp instructions instead of ret
• More flexible than ROP in some architectures
• Harder to detect in some systems

SOP (Syscall-Oriented Programming):

• Chains syscall instructions
• Direct system call execution without libc
• Powerful for privilege escalation

Basic Usage

Command	Purpose
ropper -f binary	Load binary and analyze
ropper --file binary	Same as above
ropper -f binary -i	Interactive mode
ropper -f binary --list	List all gadgets found
ropper --help	Display help information
ropper --version	Show version

Loading and Inspecting Binaries

# Load single binary
ropper -f /bin/bash

# Specify architecture explicitly
ropper -f binary --arch=x86_64

# Load with options
ropper -f binary -r --inst-count 3

# Load and jump to interactive mode
ropper -f binary -i

Gadget Finding

Basic Gadget Search

Command	Purpose
ropper -f binary --search "pop rdi"	Find specific gadget
ropper -f binary -s "mov rax"	Short form search
ropper -f binary --inst-count 2	Limit gadget size (2 instructions)
ropper -f binary --inst-count 3	Slightly larger gadgets
ropper -f binary --inst-count 1	Single-instruction gadgets

Practical Gadget Searches

# Pop rdi; ret (common x64 argument setting)
ropper -f binary -s "pop rdi; ret"

# Pop rsi; ret
ropper -f binary -s "pop rsi; ret"

# Set rax to syscall number (execve = 59 on x64)
ropper -f binary -s "mov rax, 0x3b"

# Syscall gadgets
ropper -f binary -s "syscall"

# xor rax, rax (clear register)
ropper -f binary -s "xor rax, rax"

# Write to memory
ropper -f binary -s "mov [rdi], rax"

Advanced Search Patterns

# Regex search
ropper -f binary -s "pop r.* ret" --filter="x64"

# Search with constraints
ropper -f binary -s "pop rdi" --quality high

# Search across sections
ropper -f binary -s "pop rsi" --all

# Search in specific section
ropper -f binary -s "pop rax" -o .text

Gadget Chain Building

# Find gadgets for specific register manipulation
ropper -f binary --search "pop rdi; ret" --chain "exec"
ropper -f binary --search "pop rsi; ret"
ropper -f binary --search "pop rdx; ret"

# Build complete ROP chain
ropper -f binary --chain "exec" /bin/sh

Interactive Mode

# Start interactive shell
ropper -f binary -i

# Available in interactive mode:
# search <pattern> - Search gadgets
# list - Display all gadgets
# file <binary> - Load different binary
# help - Show commands
# quit - Exit

Interactive Mode Commands

Command	Purpose
search pop rdi	Find “pop rdi” gadgets
list	Show loaded gadgets
file /path/to/binary	Load binary
hex	Display hex dump
asm	Assemble instructions
disasm	Disassemble bytes
semantic	Semantic gadget search
opcode	Find by opcode

Semantic Gadget Search

# Find gadgets that perform specific operations
ropper -f binary --semantic "rax=0"  # Zero out rax
ropper -f binary --semantic "rdi=rsi" # Copy rsi to rdi
ropper -f binary --semantic "rax=rdi" # Copy rdi to rax

# Complex semantics
ropper -f binary --semantic "rax=rdi+rsi"
ropper -f binary --semantic "rdi=[rsi]"

ROP Chain Generation

# Generate exec chain
ropper -f binary --chain "exec" /bin/sh

# Generate write chain
ropper -f binary --chain "write" <address> <data>

# Mprotect chain (mark memory executable)
ropper -f binary --chain "mprotect"

# Read chain
ropper -f binary --chain "read"

Binary Information

Command	Purpose
ropper -f binary --info	Display binary information
ropper -f binary --checksec	Check security features
ropper -f binary --sections	List sections
ropper -f binary --imports	Show imported functions
ropper -f binary --symbols	Display symbols

Security Checks

# Check exploit mitigations
ropper -f binary --checksec

# Look for ASLR indicators
ropper -f binary --info | grep -i aslr

# Identify position-independent code
ropper -f binary --info | grep -i pie

# Check for stack canary
ropper -f binary --info | grep -i canary

Output and Export

Command	Purpose
ropper -f binary --list --export json	Export to JSON
ropper -f binary --list --export python	Export Python code
ropper -f binary --list --export raw	Raw gadget output
ropper -f binary --list > gadgets.txt	Save to file

JSON Export Example

ropper -f binary --list --export json > gadgets.json

# Parse JSON with jq
cat gadgets.json | jq '.gadgets[] | select(.asm | contains("pop rdi"))'

Filtering Results

# Filter by architecture
ropper -f binary --arch=x86_64 -s "pop rdi"

# Filter by instruction count
ropper -f binary -s "pop" --inst-count 1

# Quality filtering
ropper -f binary -s "pop rdi" --quality medium

# Address range filtering
ropper -f binary -s "pop rdi" --range="0x400000-0x410000"

Exploit Development Workflow

Step 1: Identify Function Prologue/Epilogue

# Find function prologues
ropper -f binary -s "push rbp; mov rbp, rsp"

# Find returns
ropper -f binary -s "ret"

Step 2: Find Argument-Setting Gadgets

# First argument (rdi in x64)
ropper -f binary -s "pop rdi; ret"

# Second argument (rsi in x64)
ropper -f binary -s "pop rsi; ret"

# Third argument (rdx in x64)
ropper -f binary -s "pop rdx; ret"

Step 3: Locate System Calls

# Find syscall instruction
ropper -f binary -s "syscall"

# Alternative: int 0x80 for 32-bit
ropper -f binary -s "int 0x80"

Step 4: Build Chain

# Example: execve("/bin/sh", NULL, NULL)
ropper -f binary --chain "exec" /bin/sh

Multi-Binary Analysis

# Load multiple binaries
ropper -f binary1 -f binary2 -s "pop rdi"

# Compare gadgets across binaries
ropper -f binary1 -s "pop rdi" > gadgets1.txt
ropper -f binary2 -s "pop rdi" > gadgets2.txt
diff gadgets1.txt gadgets2.txt

Advanced Techniques

Searching by Opcode

# Find byte patterns
ropper -f binary --opcode "5f c3"  # pop rdi; ret

# Partial opcode search
ropper -f binary --opcode "5f"     # pop rdi

Branch Gadgets

# Conditional jumps
ropper -f binary -s "je"
ropper -f binary -s "jne"
ropper -f binary -s "jz"
ropper -f binary -s "jmp"

Load/Store Gadgets

# Memory writes
ropper -f binary -s "mov [rdi], rax"

# Memory reads
ropper -f binary -s "mov rax, [rdi]"

# Indirect writes
ropper -f binary -s "mov [rdi], rsi"

Common Gadget Patterns

x86-64 System Call Pattern

# Find the syscall number setup
ropper -f binary -s "mov rax, 0x3b"  # execve syscall

# Stack setup
ropper -f binary -s "mov rsi, 0"
ropper -f binary -s "mov rdx, 0"

# Syscall
ropper -f binary -s "syscall"

x86 (32-bit) Patterns

# Arguments via stack
ropper -f binary -s "push" --arch=x86

# Call instruction
ropper -f binary -s "call" --arch=x86

# System call
ropper -f binary -s "int 0x80" --arch=x86

Performance Optimization

# Cache gadgets (faster subsequent searches)
ropper -f binary --cache

# Clear cache if needed
ropper -f binary --clear-cache

# Limit search to text section
ropper -f binary -s "pop rdi" -o .text

# Quick scan (fewer gadgets found)
ropper -f binary --fast -s "pop"

Exploit Script Generation

# Generate Python ROP builder template
ropper -f binary --chain "exec" /bin/sh --export python

# Manual chain building (example in Python):
# rop = ROP(binary)
# rop.call('execve', ['/bin/sh', NULL, NULL])
# payload = rop.build()

Integration with Other Tools

With GDB

# Find gadget addresses
ropper -f binary -s "pop rdi; ret"

# Set breakpoint in GDB
gdb binary
(gdb) break *0x<gadget_address>
(gdb) run <args>

With Pwntools

#!/usr/bin/env python3
from pwntools import *

binary = ELF('./binary')

# Find gadgets programmatically
rop = ROP(binary)
rop.rdi = 0x400000
rop.call('execve', ['/bin/sh', 0, 0])
payload = rop.build()

With Radare2

# Compare with radare2 analysis
r2 binary
> /r pop rdi  # Search in radare2

# Export from ropper
ropper -f binary -s "pop rdi" > ropper_gadgets.txt

Troubleshooting

# Binary not loading
ropper -f binary --verbose

# Architecture detection issues
ropper -f binary --arch=x86_64  # Specify manually

# Too many results
ropper -f binary -s "pop" --inst-count 1  # Limit size

# Slow scanning
ropper -f binary --fast  # Quick mode

Best Practices

• Always verify gadget offsets before use (ASLR makes them dynamic)
• Test ROP chains on target system before deployment
• Document all gadget chains and their purposes
• Use semantic analysis for complex chains
• Combine multiple sources (PLT, imports, linked libraries)
• Account for gadget variability across system updates
• Use instruction pointer validation when available

Legal and Ethical Considerations

• Use only on systems you own or have explicit authorization to test
• ROP chains are commonly used in legitimate security research
• Document all findings responsibly
• Follow responsible disclosure practices
• Maintain operational security during exploit development

Related Tools

• Pwntools - Python library for PWN/exploitation
• GDB - Debugger for gadget validation
• Radare2 - Advanced binary analysis
• Capstone - Disassembly framework
• objdump - Binary inspection
• readelf - ELF file analysis
• strace - System call tracer