svn-sscanf-advisory.txt   [plain text]

Subversion versions up to and including 1.0.2 have a buffer overflow in
the date parsing code.

Both client and server are vulnerable.  The server is vulnerable over
both httpd/DAV and svnserve (that is, over http://, https://, svn://,
svn+ssh:// and other tunneled svn+*:// methods).

Additionally, clients with shared working copies, or permissions that
allow files in the administrative area of the working copy to be
written by other users, are potentially exploitable.

Severity:
=========

Severity ranges from "Denial of Service" to, potentially, "Arbitrary
Code Execution", depending upon how skilled the attacker is and the
ABI specifics of your platform.

The server vulnerabilities can be triggered without write/commit access
to the repository.  So repositories with anonymous/public read access
are vulnerable.

Workarounds:
============

There are no workarounds except to disallow public access.  Even then
you'd still be vulnerable to attack by someone who still has access
(perhaps you trust those people, though).

Recommendations:
================

We recommend all users upgrade to 1.0.3.

References:
===========

CAN-2004-0397: subversion sscanf stack overflow via revision date
               in REPORT query

Note:
=====

There was a similar vulnerability in the Neon HTTP library up to and including
version 0.24.5.  Because Subversion ships with Neon, we have included (in
Subversion 1.0.3) Neon 0.24.6, which is being released simultaneously.
Subversion does not actually invoke the vulnerable code in Neon; we are
updating our copy of Neon simply as a reassuring gesture, so people don't
worry.  See CAN-2004-0398 for details.