CVE-2014-4814 in WebSphere Portal
Summary
by MITRE
IBM WebSphere Portal 6.1.0 through 6.1.0.6 CF27, 6.1.5 through 6.1.5.3 CF27, 7.0 through 7.0.0.2 CF28, 8.0 through 8.0.0.1 CF14, and 8.5.0 before CF03 does not properly detect recursion during entity expansion, which allows remote authenticated users to cause a denial of service (memory and CPU consumption) via a crafted XML document containing a large number of nested entity references, a similar issue to CVE-2003-1564.
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Analysis
by VulDB Data Team • 04/03/2022
IBM WebSphere Portal versions 6.1.0 through 6.1.0.6 CF27, 6.1.5 through 6.1.5.3 CF27, 7.0 through 7.0.0.2 CF28, 8.0 through 8.0.0.1 CF14, and 8.5.0 before CF03 contain a critical vulnerability in their XML processing implementation that fails to properly detect recursive entity expansion patterns. This vulnerability falls under the Common Weakness Enumeration category CWE-20, which specifically addresses improper input validation, and more specifically CWE-400, which deals with unchecked resource consumption. The flaw exists in the XML parser's handling of entity references where it does not adequately monitor or limit the depth of nested entity expansions, creating a potential for exponential resource consumption.
The technical implementation of this vulnerability allows authenticated remote attackers to craft malicious XML documents that contain deeply nested entity references, creating a recursive expansion scenario that consumes excessive system resources. When the portal processes such malformed XML, the parser attempts to resolve each entity reference recursively, leading to a rapid escalation in memory consumption and cpu utilization. This behavior directly maps to the ATT&CK technique T1499.004, which describes resource exhaustion attacks targeting application availability. The vulnerability is particularly dangerous because it can be exploited by authenticated users, meaning that an attacker with valid credentials can cause significant system degradation without requiring additional privileges. The issue is reminiscent of CVE-2003-1564, which established the pattern of XML external entity vulnerabilities that can be leveraged for denial of service attacks through recursive expansion.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the entire portal infrastructure. Attackers can consume system resources until the portal becomes unresponsive or crashes entirely, affecting all users who depend on the portal services. Memory exhaustion can lead to system instability, while excessive cpu consumption can degrade performance for legitimate users and potentially cause cascading failures in dependent systems. Organizations running affected WebSphere Portal versions face significant risk as this vulnerability can be exploited without requiring special privileges beyond authentication access. The exponential nature of resource consumption means that even relatively small crafted XML documents can cause substantial system impact, making this a particularly effective vector for denial of service attacks.
Mitigation strategies for this vulnerability should focus on both immediate patching and implementation of defensive controls. Organizations must apply the appropriate IBM security fixes and cumulative fixes for their specific WebSphere Portal version to address the root cause. Network-level defenses including xml firewall rules and content filtering can help detect and block suspicious xml patterns before they reach the portal parser. Input validation measures should be implemented to limit the maximum depth of entity references and the overall size of xml documents processed by the portal. Additionally, monitoring systems should be configured to detect unusual resource consumption patterns that may indicate exploitation attempts. The implementation of these controls aligns with ATT&CK technique T1070.004, which emphasizes the use of application whitelisting and input validation to prevent exploitation of application vulnerabilities. Regular security assessments and vulnerability scanning should be conducted to ensure that the portal remains protected against similar recursive entity expansion attacks.