Cisco Web Security Appliance Privilege Escalation Vulnerability

Vulnerability

A vulnerability in the configuration management interface of Cisco AsyncOS for Cisco Web Security Appliance (WSA) allows an authenticated, remote attacker to inject arbitrary commands. The flaw is due to insufficient validation of user-supplied XML input when uploading configuration files via the web interface. Affected versions are those prior to the fixed releases noted in the advisory; customers should consult the advisory for specific version details. [1]

Exploitation

An attacker must possess a valid user account with the rights to upload configuration files to the affected WSA device. The attack is carried out remotely over the network by uploading a crafted XML configuration file that contains embedded scripting code. The uploaded file is processed by the configuration management component, and the embedded code is executed on the underlying operating system.

Impact

Successful exploitation allows the attacker to execute arbitrary commands on the underlying operating system with root privileges. This effectively grants full control over the affected device, resulting in a complete compromise of confidentiality, integrity, and availability.

Mitigation

Cisco has released free software updates that address this vulnerability. Users should upgrade to the appropriate fixed version as indicated in the Cisco Security Advisory. No workarounds are available, and it is recommended that customers with service contracts obtain the fixes through normal channels. Those without contracts should contact the Cisco Technical Assistance Center (TAC) to request the upgrade. [1]