FreeBSD today released a core (kernel) patched to plug “arc4random predictable sequence vulnerability” security hole in its operating systems version 6.x and 7.x stable release. When the arc4random random number generator is initialized, there may be inadequate entropy to meet the needs of kernel systems which rely on arc4random; and it may take up to 5 minutes before arc4random is reseeded with secure entropy from the Yarrow random number generator. All security-related kernel subsystems that rely on a quality random number generator are subject to a wide range of possible attacks. This update has been rated as having important security impact.
The BIND DNS implementation does not randomize the UDP source port when doing remote queries, and the query id alone does not provide adequate randomization.