Asterisk Open Source 1.8.x before 1.8.28.1, 11.x before 11.10.1, and 12.x before 12.3.1 and Certified Asterisk 1.8.15 before 1.8.15-cert6 and 11.6 before 11.6-cert3 allows remote attackers to cause a denial of service (connection consumption) via a large number of (1) inactive or (2) incomplete HTTP connections.
http://www.securityfocus.com/archive/1/532415/100/0/threaded
http://packetstormsecurity.com/files/127089/Asterisk-Project-Security-Advisory-AST-2014-007.html
http://downloads.asterisk.org/pub/security/AST-2014-007.html