Cisco ASA libsrtp DoS (CSCux00686)
High Nessus Plugin ID 91759
SynopsisThe remote device is missing a vendor-supplied security patch.
DescriptionThe remote Cisco Adaptive Security Appliance (ASA) is missing vendor-supplied security patches, and it is configured to use the Phone Proxy feature. It is, therefore, affected by an integer underflow condition in the Secure Real-Time Transport Protocol (SRTP) library due to improper validation of certain fields of SRTP packets.
An unauthenticated, remote attacker can exploit this, via specially crafted SRTP packets, to cause packet decryption to fail, resulting in a denial of service condition.
SolutionApply the relevant patch or workaround referenced in Cisco Security Advisory cisco-sa-20160420-libsrtp.