CVE-2011-3287 in Jabber Extensible Communications Platform
Summary
by MITRE
Cisco Jabber Extensible Communications Platform (aka Jabber XCP) 2.x through 5.4.x before 5.4.0.27581 and 5.8.x before 5.8.1.27561 does not properly detect recursion during entity expansion, which allows remote attackers to cause a denial of service (memory and CPU consumption, and process crash) via a crafted XML document containing a large number of nested entity references, aka Bug ID CSCtq78106, a similar issue to CVE-2003-1564.
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Analysis
by VulDB Data Team • 01/14/2018
The vulnerability described in CVE-2011-3287 affects Cisco Jabber Extensible Communications Platform, a unified communications solution that enables voice, video, and messaging capabilities within enterprise environments. This flaw exists in versions 2.x through 5.4.x before 5.4.0.27581 and 5.8.x before 5.8.1.27561, representing a significant security weakness in communication infrastructure software. The issue manifests as improper detection of recursion during entity expansion within XML processing mechanisms, creating a condition where maliciously crafted XML documents can trigger excessive resource consumption and system instability.
The technical implementation of this vulnerability stems from insufficient validation of XML entity references during parsing operations. When the Jabber XCP platform processes XML documents containing deeply nested entity references, it fails to properly track or limit the recursion depth of entity expansion. This allows an attacker to construct XML documents with thousands or millions of nested entity references that, when processed, cause the system to allocate excessive memory resources and consume CPU cycles in an unbounded manner. The vulnerability directly relates to CWE-611, which addresses improper restriction of XML external entity reference, and shares similarities with CVE-2003-1564, which documented a related issue in XML parsers. The flaw operates at the core of XML processing libraries where entity expansion should be carefully monitored to prevent resource exhaustion attacks.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it can severely disrupt enterprise communication systems and potentially compromise business continuity. When exploited, the vulnerability causes memory exhaustion that leads to process crashes and system instability, affecting critical communication services for organizations relying on Cisco Jabber for their unified communications infrastructure. Attackers can leverage this weakness to repeatedly send malicious XML documents to targeted systems, creating sustained resource depletion that may require system restarts or manual intervention to resolve. The vulnerability affects organizations using Cisco Jabber in enterprise environments where communication reliability is paramount, making it particularly dangerous for mission-critical operations.
Mitigation strategies for CVE-2011-3287 should focus on both immediate patching and defensive configuration measures. Organizations must upgrade to patched versions of Cisco Jabber XCP, specifically versions 5.4.0.27581 or later for the 5.4.x branch and 5.8.1.27561 or later for the 5.8.x branch to address the root cause. Network administrators should implement XML filtering and validation at network boundaries to prevent malformed XML documents from reaching vulnerable systems, utilizing firewalls and intrusion prevention systems with XML inspection capabilities. Additionally, implementing rate limiting and resource monitoring can help detect and prevent exploitation attempts before they cause significant system impact. The vulnerability demonstrates the importance of proper XML security practices and adheres to ATT&CK technique T1499.004, which covers network denial of service attacks, making comprehensive defense-in-depth strategies essential for protecting against such threats.