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Gentoo Linux Security Advisory                           GLSA 202403-04
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                                           https://security.gentoo.org/
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 Severity: High
    Title: XZ utils: Backdoor in release tarballs
     Date: March 29, 2024
     Bugs: #928134
       ID: 202403-04

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Synopsis
========

A backdoor has been discovered in XZ utils that could lead to remote
compromise of systems.

Background
==========

XZ Utils is free general-purpose data compression software with a high
compression ratio.

Affected packages
=================

Package            Vulnerable    Unaffected
-----------------  ------------  ------------
app-arch/xz-utils  >= 5.6.0      < 5.6.0

Description
===========

A backdoor has been discovered in XZ utils. Please review the CVE
identifier referenced below for details.

Impact
======

Our current understanding of the backdoor is that is does not affect
Gentoo systems, because

1. the backdoor only appears to be included on specific systems and
Gentoo does not qualify;
2. the backdoor as it is currently understood targets OpenSSH patched to
work with systemd-notify support. Gentoo does not support or include
these patches;

Analysis is still ongoing, however, and additional vectors may still be
identified. For this reason we are still issuing this advisory as if
that will be the case.

Workaround
==========

There is no known workaround at this time.

Resolution
==========

All XZ utils users should downgrade to the latest version before the
backdoor was introduced:

  # emerge --sync
  # emerge --ask --oneshot --verbose "<app-arch/xz-utils-5.6.0"

References
==========

[ 1 ] CVE-2024-3094
      https://nvd.nist.gov/vuln/detail/CVE-2024-3094

Availability
============

This GLSA and any updates to it are available for viewing at
the Gentoo Security Website:

 https://security.gentoo.org/glsa/202403-04

Concerns?
=========

Security is a primary focus of Gentoo Linux and ensuring the
confidentiality and security of our users' machines is of utmost
importance to us. Any security concerns should be addressed to
security@gentoo.org or alternatively, you may file a bug at
https://bugs.gentoo.org.

License
=======

Copyright 2024 Gentoo Foundation, Inc; referenced text
belongs to its owner(s).

The contents of this document are licensed under the
Creative Commons - Attribution / Share Alike license.

https://creativecommons.org/licenses/by-sa/2.5