Perl Module-Signature module: Arbitrary code execution

Background

The Perl Module::Signature module adds signing capabilities to CPAN modules.

Description

The ‘cpansign verify’ command will automatically download keys and use them to check the signature of CPAN packages via the SIGNATURE file. If an attacker were to replace this (SHA1) with a special unknown cipher (e.g. ‘Special’) and were to include in the distribution a ‘Digest/Special.pm’, the code in this Perl module would be executed when ‘cpansign -verify’ is run.

Impact

A remote attacker could possibly execute arbitrary code with the privileges of the process.

Workaround

There is no known workaround at this time.

Resolution

All users of the Module-Signature Perl module should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose
 ">=dev-perl/Module-Signature-0.720.0"