Cisco Web Security Appliance HTTP Length Denial of Service Vulnerability

A vulnerability in HTTP request parsing in Cisco AsyncOS for the Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition when the proxy process unexpectedly restarts.

The vulnerability occurs because the affected software does not properly allocate space for the HTTP header and any expected HTTP payload. An attacker could exploit this vulnerability by sending a crafted HTTP request to the affected device. An exploit could allow the attacker to cause a DoS condition when the proxy process unexpectedly reloads, which can cause traffic to be dropped.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is available at the following link:

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160518-wsa3[“https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160518-wsa3”]