Bug#1037948: xmltooling: Parsing of KeyInfo elements can cause remote resource access

[Ferenc Wágner]

Source: xmltooling
Severity: important
Tags: patch upstream security

Shibboleth Service Provider Security Advisory [12 June 2023]

An updated version of the XMLTooling library that is part of the
OpenSAML and Shibboleth Service Provider software is now available
which corrects a server-side request forgery (SSRF) vulnerability.

Parsing of KeyInfo elements can cause remote resource access.
=============================================================
Including certain legal but "malicious in intent" content in the
KeyInfo element defined by the XML Signature standard will result
in attempts by the SP's shibd process to dereference untrusted
URLs.

While the content of the URL must be supplied within the message
and does not include any SP internal state or dynamic content,
there is at minimum a risk of denial of service, and the attack
could be combined with others to create more serious vulnerabilities
in the future.

This issue is *not* specific to the V3 XMLTooling software and is
believed to impact all versions prior to V3.2.4.

Recommendations
===============
Update to V3.2.4 or later of the XMLTooling library, which is
now available. Note that on Linux and similar platforms, upgrading
this component will require restarting the shibd process to correct
the bug.

The updated version of the library has been included in a V3.4.1.3
patch release of the Service Provider software on Windows.

Other Notes
===========
The xmltooling git commit containing the fix for this issue is
6080f6343f98fec085bc0fd746913ee418cc9d30 and may be in general terms
applicable to V2 of the library.

Credits
=======
Juriën de Jong, an independent security researcher in the Netherlands

URL for this Security Advisory:
https://shibboleth.net/community/advisories/secadv_20230612.txt