CVE-2016-1382 in Web Security Appliance
Summary
by MITRE
Cisco AsyncOS before 8.5.3-069 and 8.6 through 8.8 on Web Security Appliance (WSA) devices mishandles memory allocation for HTTP requests, which allows remote attackers to cause a denial of service (proxy-process reload) via a crafted request, aka Bug ID CSCuu02529.
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Analysis
by VulDB Data Team • 10/14/2024
Cisco AsyncOS versions prior to 8.5.3-069 and 8.6 through 8.8 running on Web Security Appliance devices contain a memory allocation vulnerability that manifests when processing HTTP requests. This flaw occurs during the proxy processing phase where the system fails to properly manage memory resources when handling specially crafted HTTP requests. The vulnerability stems from inadequate input validation and memory management routines within the HTTP request handling component of the AsyncOS kernel. Attackers can exploit this weakness by sending specifically crafted HTTP requests that trigger improper memory allocation behaviors, leading to system instability and subsequent proxy process reloads.
The technical implementation of this vulnerability involves the manipulation of HTTP request parameters that cause the system to allocate memory in unexpected ways. When the WSA device processes these malformed requests, the memory allocation routines fail to properly handle the request structure, resulting in memory corruption or exhaustion conditions. This memory handling failure directly impacts the proxy process that manages HTTP traffic, causing the system to automatically reload the proxy service as a protective measure. The reload process effectively disrupts legitimate traffic and creates a denial of service condition for authorized users.
The operational impact of this vulnerability extends beyond simple service disruption as it affects the availability of web security services critical to enterprise networks. Organizations relying on Cisco WSA appliances for web filtering, content inspection, and security enforcement face potential business interruption when this vulnerability is exploited. The automatic proxy reload mechanism, while designed to protect the system, creates a cascading effect that can lead to extended downtime and potential loss of security monitoring capabilities. Network administrators may experience difficulty maintaining consistent security posture while the system recovers from the reload events.
This vulnerability aligns with CWE-129, which addresses improper validation of input ranges, and CWE-131, concerning improper handling of memory allocation failures. The attack pattern follows the MITRE ATT&CK framework's T1499.004 technique for network denial of service, specifically targeting application-level services. Organizations should implement immediate patch management procedures to upgrade to Cisco AsyncOS versions 8.5.3-069 or later, or 8.6.1-020 and higher for affected 8.6 releases, and 8.8.1-007 and higher for 8.8 releases. Network segmentation and monitoring of HTTP traffic patterns can provide early detection of exploitation attempts, while implementing rate limiting and request validation mechanisms offers additional defense-in-depth measures against similar memory allocation attacks.