[issue23505] Urlparse insufficient validation leads to open redirect

[Yassine ABOUKIR]

Yassine ABOUKIR added the comment:

Yes, exploiting this bug an attacker may redirect a specific vitim to a malicious website, in our case evil.com

>>> x = urlparse("////evil.com")

///evil.com will be parsed as relative-path URL which is the correct expected behaviour

>>> print x
>>> ParseResult(scheme='', netloc='', path='//evil.com', params='', query='', fragment='')

As you see two slashes are removed and it is marked as a relative-path URL but when we reconstruct the URL using urlunparse() function, the URL is treated as an absolute URL to which you will be redirected.

>>> x = urlunparse(urlparse("////evil.com"))
>>> urlparse(x)
ParseResult(scheme='', netloc='evil.com', path='', params='', query='', fragment='')

----------

_______________________________________
Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue23505>
_______________________________________