Asterisk IAX2 Call Number Exhaustion DoS
Medium Nessus Plugin ID 40885
SynopsisThe remote VoIP service is susceptible to a denial of service attack.
DescriptionThe version of Asterisk running on the remote host appears to be using an older implementation of the IAX2 protocol that does not support call token validation. Due to a design flaw in the protocol, a remote attacker could send a large number of messages, exhausting all available call numbers in the process. This would result in a denial of service to legitimate users.
SolutionUpgrade to the relevant version of Asterisk referenced in the vendor's advisory.