CVE-2002-1169 in Websphere Caching Proxy Server
Summary
by MITRE
IBM Web Traffic Express Caching Proxy Server 3.6 and 4.x before 4.0.1.26 allows remote attackers to cause a denial of service (crash) via an HTTP request to helpout.exe with a missing HTTP version number, which causes ibmproxy.exe to crash.
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Analysis
by VulDB Data Team • 09/07/2025
The vulnerability identified as CVE-2002-1169 affects IBM Web Traffic Express Caching Proxy Server versions 3.6 and 4.x prior to 4.0.1.26, representing a critical denial of service weakness that can be exploited remotely by attackers to crash the targeted system. This issue specifically manifests when the caching proxy server receives an HTTP request directed to the helpout.exe component without a properly specified HTTP version number, leading to a catastrophic failure in the ibmproxy.exe process that manages the proxy functionality. The vulnerability stems from inadequate input validation within the HTTP request processing mechanism of the proxy server software, where the system fails to properly handle malformed HTTP requests that lack essential version information.
The technical flaw resides in the protocol handling layer of the IBM Web Traffic Express proxy server implementation, where the software does not adequately validate the presence and format of the HTTP version field in incoming requests. This weakness creates a condition where the ibmproxy.exe process becomes vulnerable to malformed HTTP requests that exploit the absence of proper version specification. According to CWE classification, this vulnerability maps to CWE-129: Improper Validation of Array Index, as the system fails to validate the integrity of input parameters before processing them, and potentially to CWE-691: Insufficient Control Flow Management, since the control flow becomes unstable when encountering unexpected HTTP version specifications. The attack vector involves sending a specially crafted HTTP request to the helpout.exe endpoint without including the HTTP version number, which triggers an unhandled exception in the proxy server's processing logic.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be exploited by remote attackers to systematically crash the caching proxy server, effectively rendering the network traffic management system unavailable. Organizations relying on IBM Web Traffic Express for content caching and traffic management would experience complete service interruption, potentially affecting thousands of users depending on the scale of the network infrastructure. The vulnerability particularly affects enterprise networks that depend on proxy servers for traffic optimization, content filtering, and bandwidth management, where a successful exploitation could result in significant operational downtime and potential revenue loss. From an ATT&CK framework perspective, this vulnerability aligns with T1499.004: Endpoint Denial of Service, where adversaries can cause system unavailability through targeted attacks against specific services.
Mitigation strategies for CVE-2002-1169 should prioritize immediate implementation of the vendor-provided security patches, specifically upgrading to IBM Web Traffic Express Caching Proxy Server version 4.0.1.26 or later, which includes proper input validation for HTTP requests. Network administrators should also implement additional protective measures such as deploying intrusion detection systems that can identify and block malformed HTTP requests targeting the helpout.exe endpoint, and configuring firewall rules to restrict access to sensitive proxy server components. Organizations should consider implementing rate limiting mechanisms to prevent abuse of the vulnerable endpoint and establish monitoring protocols to detect unusual traffic patterns that may indicate attempted exploitation. Additionally, regular security assessments and vulnerability scanning should be conducted to identify similar weaknesses in other network infrastructure components, as this vulnerability demonstrates the importance of robust input validation in network services. The incident also highlights the necessity of maintaining up-to-date security patches across all network infrastructure components to prevent exploitation of known vulnerabilities that can lead to complete system compromise.