CVE-2016-1381 in Web Security Appliance
Summary
by MITRE
Memory leak in Cisco AsyncOS 8.5 through 9.0 before 9.0.1-162 on Web Security Appliance (WSA) devices allows remote attackers to cause a denial of service (memory consumption) via an HTTP file-range request for cached content, aka Bug ID CSCuw97270.
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Analysis
by VulDB Data Team • 10/14/2024
The vulnerability identified as CVE-2016-1381 represents a critical memory leak issue affecting Cisco AsyncOS versions 8.5 through 9.0 before 9.0.1-162 on Web Security Appliance devices. This flaw manifests when the system processes HTTP file-range requests for cached content, creating a condition where memory resources gradually become consumed without proper release. The vulnerability operates through a specific attack vector involving crafted HTTP requests that target cached files, leading to progressive memory exhaustion over time.
The technical implementation of this vulnerability stems from improper memory management within the Web Security Appliance's handling of HTTP range requests. When a client makes a range request for cached content, the system fails to correctly free allocated memory resources associated with the request processing. This memory leak occurs repeatedly with each malicious request, causing the appliance's memory consumption to increase continuously until system resources are depleted. The flaw is classified under CWE-401 as a failure to release memory resources, which directly relates to the improper handling of memory allocation and deallocation processes within the affected software components.
The operational impact of this vulnerability extends beyond simple resource exhaustion to potentially compromise the availability and integrity of web security services. Attackers can exploit this weakness remotely without requiring authentication, making it particularly dangerous in production environments where continuous availability is critical. The memory consumption pattern creates a gradual degradation of service performance before ultimately resulting in complete denial of service, where the appliance becomes unresponsive and unable to process legitimate web traffic. This type of attack aligns with ATT&CK technique T1499.004 for network denial of service, where adversaries leverage system resource exhaustion to disrupt services.
Organizations utilizing affected Cisco WSA devices face significant operational risks including service interruptions, reduced network performance, and potential security exposure through service disruption. The vulnerability's remote exploitability means that attackers can target these systems from outside the network perimeter, potentially leading to extended service outages and increased operational costs for system recovery. The memory leak affects the appliance's ability to maintain proper caching functionality, which impacts the overall web security posture and can result in increased network latency for legitimate users. This vulnerability demonstrates the importance of regular security updates and patch management in maintaining network infrastructure integrity. Organizations should implement monitoring solutions to detect unusual memory consumption patterns and establish automated alerting mechanisms to identify potential exploitation attempts. The remediation process requires applying the appropriate Cisco security patches and updates to bring the system to version 9.0.1-162 or later, ensuring that the memory management fixes are properly implemented and tested in production environments before deployment.