A vulnerability in the Dynamic Vectoring and Streaming (DVS) Engine implementation of Cisco AsyncOS Software for Cisco Secure Web Appliance could allow an unauthenticated, remote attacker to bypass the anti-malware scanner, allowing malicious archive files to be downloaded. This vulnerability is due to improper handling of certain archive files. An attacker could exploit this vulnerability by sending a crafted archive file, which should be blocked, through an affected device. A successful exploit could allow the attacker to bypass the anti-malware scanner and download malware onto an end user workstation. The downloaded malware will not automatically execute unless the end user extracts and launches the malicious file.