A vulnerability in the Advanced Malware Protection (AMP) file filtering feature of Cisco AsyncOS Software for Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to bypass a configured AMP file filtering rule. The file types affected are zipped or archived file types. The vulnerability is due to incorrect and different file hash values when AMP scans the file. An attacker could exploit this vulnerability by sending a crafted email file attachment through the targeted device. An exploit could allow the attacker to bypass a configured AMP file filter. Cisco Bug IDs: CSCvf52943.