CVE-2011-1502 in Liferay
Summary
by MITRE
Liferay Portal Community Edition (CE) 6.x before 6.0.6 GA, when Apache Tomcat is used, allows remote authenticated users to read arbitrary files via an entity declaration in conjunction with an entity reference, related to an XML External Entity (aka XXE) issue.
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Analysis
by VulDB Data Team • 11/06/2021
The vulnerability identified as CVE-2011-1502 represents a critical XML External Entity (XXE) flaw discovered in Liferay Portal Community Edition versions 6.x prior to 6.0.6 GA. This security weakness specifically affects installations utilizing Apache Tomcat as the underlying application server, creating a significant attack surface for remote authenticated adversaries. The vulnerability stems from insufficient input validation and processing of XML data within the portal's configuration and content management components, where user-supplied XML documents are parsed without proper security restrictions.
The technical exploitation of this XXE vulnerability occurs through a sophisticated attack vector involving both entity declaration and entity reference mechanisms within XML processing. An authenticated attacker can craft malicious XML payloads that declare external entities and subsequently reference them within the application's XML parsing context. This allows the attacker to leverage the XML parser's capability to resolve external references, enabling unauthorized file access on the server hosting the Liferay portal. The vulnerability specifically targets the XML processing libraries used by Liferay when integrated with Apache Tomcat, exploiting the inherent behavior of XML parsers that automatically resolve external entity references without proper sanitization.
Operationally, this vulnerability presents a severe risk to organizations using Liferay Portal CE 6.x with Apache Tomcat, as it allows attackers to read arbitrary files from the server filesystem. The impact extends beyond simple information disclosure, potentially enabling attackers to access sensitive configuration files, database connection details, application source code, and other confidential data stored on the server. The authenticated nature of the vulnerability means that attackers need valid user credentials, but once obtained, they can leverage this weakness to escalate their access and potentially compromise the entire application stack. The attack can be particularly devastating in environments where Liferay serves as a central portal for enterprise content management, document sharing, or user authentication services.
Organizations should immediately implement comprehensive mitigations including upgrading to Liferay Portal Community Edition 6.0.6 GA or later versions that contain proper XXE protection mechanisms. The fix involves implementing proper XML parser configurations that disable external entity resolution and DTD processing, effectively preventing the exploitation of XXE vulnerabilities. Security teams should also consider implementing web application firewalls with XXE detection capabilities, monitoring for suspicious XML content patterns, and conducting thorough security assessments of XML processing components throughout the application. Additionally, implementing principle of least privilege access controls and regular security audits of XML handling code can significantly reduce the attack surface and potential impact of such vulnerabilities. This issue aligns with CWE-611 (Improper Restriction of XML External Entity Reference) and represents a common attack pattern categorized under ATT&CK technique T1213.002 (Data from Information Repositories) with potential for lateral movement and privilege escalation within compromised environments.