[arch-security] [ASA-201705-20] lynis: arbitrary file overwrite

[Levente Polyak]

Arch Linux Security Advisory ASA-201705-20
==========================================

Severity: High
Date    : 2017-05-22
CVE-ID  : CVE-2017-8108
Package : lynis
Type    : arbitrary file overwrite
Remote  : No
Link    : https://security.archlinux.org/AVG-278

Summary
=======

The package lynis before version 2.5.0-1 is vulnerable to arbitrary
file overwrite.

Resolution
==========

Upgrade to 2.5.0-1.

# pacman -Syu "lynis>=2.5.0-1"

The problem has been fixed upstream in version 2.5.0.

Workaround
==========

None.

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

Michael Scherer discovered that some Lynis tests reuse the same
temporary file. As some tests remove the temporary file, this might
give an attacker the possibility to perform a link following attack.
While timing must be perfect, there is a very small time window in
which the attack can recreate the temporary file and symlink it to
another resource, like a file. In this case data may be overwritten, or
possibly executed.

Impact
======

A local unprivileged attacker is able to overwrite arbitrary files on
the filesystem possibly leading to privilege escalation.

References
==========

https://bugs.archlinux.org/task/54067
https://cisofy.com/security/cve/cve-2017-8108/
https://security.archlinux.org/CVE-2017-8108

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