Arch Linux Security Advisory ASA-201603-9
========================================
Severity: Medium
Date    : 2016-03-10
CVE-ID  : CVE-2016-2381
Package : perl
Type    : improper input validation
Remote  : Yes
Link    : https://wiki.archlinux.org/title/CVE

Summary
======
The package perl before version 5.22.1-2 is vulnerable to improper input
validation leading to malicious environment variable propagation.

Resolution
=========
Upgrade to 5.22.1-2.

# pacman -Syu "perl>=5.22.1-2"

The problem has been fixed upstream in version 5.22.1.

Workaround
=========
None.

Description
==========
Stephane Chazelas discovered a bug in the environment handling in Perl.
Perl provides a Perl-space hash variable, %ENV, in which environment
variables can be looked up. If a variable appears twice in envp, only
the last value would appear in %ENV, but getenv would return the first.
Perl's taint security mechanism would be applied to the value in %ENV,
but not to the other rest of the environment. This could result in an
ambiguous environment causing environment variables to be propagated to
subprocesses, despite the protections supposedly offered by taint checking.

Impact
=====
A remote attacker is able to bypass the taint checking and propagate
malicious environment variables to subprocesses.

References
=========
https://access.redhat.com/security/cve/CVE-2016-2381
https://bugs.archlinux.org/task/48482
https://perl5.git.perl.org/perl.git/commitdiff/ae37b791a