Amazon Linux AMI Security Advisory: ALAS-2013-161
Advisory Release Date: 2014-09-15 22:34 Pacific
It was discovered that dnsmasq, when used in combination with certain libvirtd configurations, could incorrectly process network packets from network interfaces that were intended to be prohibited. A remote, unauthenticated attacker could exploit this flaw to cause a denial of service via DNS amplification attacks. (CVE-2012-3411 )
Run yum update dnsmasq to update your system.