CVE-2011-5009 in CoDeSys
Summary
by MITRE
The CmpWebServer.dll module in the Control service in 3S CoDeSys 3.4 SP4 Patch 2 allows remote attackers to cause a denial of service (NULL pointer dereference) via (1) a crafted Content-Length in an HTTP POST or (2) an invalid HTTP request method.
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Analysis
by VulDB Data Team • 10/09/2024
The vulnerability identified as CVE-2011-5009 affects the CmpWebServer.dll module within the Control service of 3S CoDeSys 3.4 SP4 Patch 2, representing a critical security flaw that enables remote attackers to execute denial of service attacks through specific HTTP request manipulation techniques. This vulnerability exists within industrial control systems and automation software platforms, making it particularly concerning for operational technology environments where system availability is paramount for continuous operations.
The technical implementation of this vulnerability stems from inadequate input validation within the HTTP request processing logic of the embedded web server component. When the system receives a crafted Content-Length header in an HTTP POST request or an invalid HTTP request method, the CmpWebServer.dll module fails to properly validate these inputs before attempting to process them. This failure results in a NULL pointer dereference condition, where the application attempts to access memory at address zero, causing an immediate crash and subsequent system unavailability. The vulnerability specifically targets the web server's request handling mechanism, exploiting the absence of proper boundary checking and error handling for malformed HTTP requests.
The operational impact of this vulnerability extends beyond simple service disruption, as it can potentially compromise the entire control system infrastructure that relies on the CoDeSys platform for automation and monitoring. In industrial environments where 3S CoDeSys is deployed for critical processes, such as manufacturing control, power generation, or chemical processing, a successful exploitation could lead to extended downtime, production losses, and potential safety hazards. The remote nature of the attack means that adversaries can exploit this vulnerability from external networks without requiring physical access or elevated privileges, making it particularly dangerous for connected industrial systems. This vulnerability directly maps to CWE-476 which describes NULL pointer dereference conditions, and represents a classic example of how insufficient input validation can lead to system instability and availability compromise.
Mitigation strategies for CVE-2011-5009 should focus on both immediate defensive measures and long-term system hardening approaches. Organizations should implement network-level filtering to restrict access to the affected web server ports and services, particularly in operational technology environments where such exposure is unnecessary. The most effective immediate solution involves applying the vendor-provided patch or update that addresses the input validation flaws in the CmpWebServer.dll module. Additionally, implementing proper HTTP request filtering and validation at network boundaries can help detect and block malformed requests before they reach the vulnerable component. Security monitoring should be enhanced to detect unusual patterns of HTTP requests that might indicate exploitation attempts, while system administrators should consider isolating the affected systems in segmented network environments to limit potential lateral movement if exploitation occurs. The vulnerability also highlights the importance of following ATT&CK framework principles for defensive strategies, particularly in the area of privilege escalation and defense evasion techniques that attackers might employ when targeting industrial control systems. Regular vulnerability assessments and security audits should be conducted to identify similar input validation weaknesses in other industrial control system components, as this represents a common class of vulnerabilities in embedded systems and legacy automation platforms.