Amazon Linux AMI Security Advisory: ALAS-2013-254
Advisory Release Date: 2014-09-16 22:05 Pacific
A flaw was found in the way mod_nss handled the NSSVerifyClient setting for the per-directory context. When configured to not require a client certificate for the initial connection and only require it for a specific directory, mod_nss failed to enforce this requirement and allowed a client to access the directory when no valid client certificate was provided. (CVE-2013-4566 )
Run yum update mod24_nss to update your system.