CVE-2014-4834 in WebSphere Commerce
Summary
by MITRE
IBM WebSphere Commerce 6.x through 6.0.0.11 and 7.x through 7.0.0.8 does not properly detect recursion during entity expansion, which allows remote attackers to cause a denial of service (memory and CPU consumption, and application crash) 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 • 03/26/2018
IBM WebSphere Commerce versions 6.x through 6.0.0.11 and 7.x through 7.0.0.8 contain a critical vulnerability in their XML processing implementation that fails to properly detect recursive entity expansion patterns. This vulnerability manifests when the application processes malformed XML documents containing deeply nested entity references that create exponential memory and CPU consumption during parsing operations. The flaw operates by allowing attackers to construct XML documents with entities that reference other entities in a recursive manner, creating an unbounded expansion sequence that consumes system resources until the application becomes unresponsive or crashes entirely. This issue represents a classic example of a denial of service vulnerability through resource exhaustion, specifically targeting the XML parser component that handles incoming data processing requests within the commerce platform.
The technical implementation of this vulnerability stems from insufficient validation mechanisms within the XML entity expansion logic. When the WebSphere Commerce application encounters a crafted XML document with nested entity references, it fails to implement proper recursion detection algorithms that would terminate processing when entity expansion exceeds predefined thresholds. This behavior creates a condition where each entity expansion can potentially trigger further expansions, leading to exponential growth in memory consumption and processing overhead. The vulnerability is particularly dangerous because it can be exploited through standard web requests containing malformed XML data, making it accessible to remote attackers without requiring special privileges or direct system access. The issue bears striking resemblance to CVE-2003-1564, which established the pattern of XML external entity vulnerabilities that have plagued various XML parsers over the years, demonstrating the persistent nature of these parsing flaws in enterprise applications.
The operational impact of CVE-2014-4834 extends beyond simple service disruption to potentially compromise the entire commerce platform availability. Attackers can cause sustained denial of service conditions by sending carefully constructed XML requests that consume all available memory and CPU resources, effectively rendering the application unusable for legitimate users. The vulnerability can be exploited to crash application processes, leading to complete service interruption that requires manual intervention and system restarts. Additionally, the resource exhaustion can cause cascading failures throughout the system architecture, potentially affecting database connections, session management, and other critical components that depend on the commerce application's availability. Organizations running affected WebSphere Commerce versions face significant operational risks including customer service disruption, revenue loss, and potential security compliance violations due to the inability to maintain system availability.
Organizations should immediately implement mitigations including applying the relevant IBM security patches and updates that address the XML entity expansion handling logic. Network-level protections such as XML firewall rules and request size limiting can help reduce the impact of exploitation attempts, while implementing proper input validation and sanitization measures can prevent malformed XML from reaching the vulnerable parsing components. System administrators should configure monitoring alerts for unusual CPU and memory consumption patterns that may indicate exploitation attempts, and establish automated response procedures to isolate affected systems. The vulnerability aligns with CWE-400, which categorizes resource exhaustion issues in software systems, and maps to ATT&CK technique T1499.004 for network denial of service attacks. Organizations should also consider implementing application-level protections such as entity expansion limits and timeout mechanisms to prevent the vulnerable parsing logic from being triggered by malicious inputs. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other XML processing components within the enterprise infrastructure.