Updates released by Cisco for the AsyncOS operating system powering the company’s Web Security Appliance (WSA) address several high severity denial-of-service (DoS) vulnerabilities.
One of the vulnerabilities (CVE-2016-1380) is caused by the lack of proper input validation for packets in an HTTP POST request. A remote, unauthenticated attacker can cause the appliance to reload by sending it a specially crafted HTTP POST request.
The second security hole (CVE-2016-1383) is related to how the operating system handles certain HTTP response code. An unauthenticated attacker can remotely cause a DoS condition by sending a specially crafted HTTP request to the targeted device, causing it to run out of memory.
AsyncOS for Cisco WSA is also plagued by a cached file-range request issue (CVE-2016-1381) that can be exploited for a DoS attack by opening multiple connections that request file ranges through the vulnerable appliance.
Another problem identified by Cisco is related to the improper allocation of space for the HTTP header and any expected HTTP payload (CVE-2016-1382). A malicious actor can exploit this to cause a DoS condition when the proxy process restarts unexpectedly, Cisco said.
The flaws affect various versions of AsyncOS for WSA on both hardware and virtual appliances. In addition to software updates that resolve these issues, workarounds are also available in some cases.
All of the vulnerabilities were found by Cisco while resolving a support case and the company says there is no evidence of malicious exploitation.
Cisco also informed customers on Wednesday that a PoC exploit has been made available by researchers for a critical remote code execution vulnerability affecting the IKEv1 and IKEv2 in ASA software.