Cisco Web Security Appliance HTTP Load Denial of Service Vulnerability

A vulnerability in HTTP request forwarding with Cisco AsyncOS for Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition due to link saturation.

The vulnerability is due to how HTTP data ranges are downloaded from the destination server. An attacker could exploit this vulnerability by sending multiple crafted HTTP requests to the targeted device. An exploit could allow the attacker to trigger multiple simultaneous downloads for the same HTTP data. This could cause a DoS condition due to heavy traffic on the connection to the server.

Cisco has not released software updates that address this vulnerability. Workarounds that address this vulnerability are not available.

This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160914-wsa[“https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160914-wsa”]