CVE-2016-0763 in Tomcat
Summary
by MITRE
The setGlobalContext method in org/apache/naming/factory/ResourceLinkFactory.java in Apache Tomcat 7.x before 7.0.68, 8.x before 8.0.31, and 9.x before 9.0.0.M3 does not consider whether ResourceLinkFactory.setGlobalContext callers are authorized, which allows remote authenticated users to bypass intended SecurityManager restrictions and read or write to arbitrary application data, or cause a denial of service (application disruption), via a web application that sets a crafted global context.
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Analysis
by VulDB Data Team • 07/08/2022
The vulnerability identified as CVE-2016-0763 represents a critical authorization bypass flaw within Apache Tomcat's naming factory implementation. This issue exists in the ResourceLinkFactory component that handles global context settings for web applications. The vulnerability stems from insufficient validation of caller authorization when the setGlobalContext method is invoked, creating a pathway for authenticated attackers to circumvent security restrictions that should protect application data access and modification. The flaw affects multiple versions of Apache Tomcat including 7.x before 7.0.68, 8.x before 8.0.31, and 9.x before 9.0.0.M3, indicating a widespread impact across the Tomcat ecosystem.
The technical implementation of this vulnerability lies in the ResourceLinkFactory.java file where the setGlobalContext method fails to perform proper security checks before allowing context modifications. When a web application invokes this method, the system should verify that the caller has appropriate authorization rights to modify global context settings. However, the current implementation lacks these authorization checks, allowing any authenticated user with access to a web application to manipulate the global context. This flaw enables attackers to gain unauthorized access to application data that should be restricted, potentially leading to data exposure, modification, or complete application disruption. The vulnerability specifically targets the SecurityManager restrictions that are designed to protect against unauthorized access to application resources, effectively rendering these protections ineffective.
The operational impact of CVE-2016-0763 extends beyond simple data access violations to encompass significant security risks including potential denial of service conditions. Attackers can leverage this vulnerability to read arbitrary application data, write to application resources, or cause application disruption that may result in complete service unavailability. The authenticated nature of the attack means that attackers do not require special privileges beyond having an account within the application environment, making this vulnerability particularly dangerous in multi-user environments. Organizations running affected versions of Apache Tomcat face potential data breaches, application compromise, and service disruption that could impact business operations and customer data security.
Mitigation strategies for CVE-2016-0763 focus primarily on upgrading to patched versions of Apache Tomcat where the authorization checks have been properly implemented. System administrators should immediately upgrade to versions 7.0.68, 8.0.31, or 9.0.0.M3 and later to address this vulnerability. Additionally, organizations should implement network segmentation and access controls to limit exposure of Tomcat instances to untrusted networks. Security monitoring should be enhanced to detect unusual context setting activities within web applications. The vulnerability aligns with CWE-863 (Incorrect Authorization) and can be mapped to ATT&CK technique T1068 (Local Privilege Escalation) and T1499 (Endpoint Denial of Service) within the MITRE ATT&CK framework, representing both authorization bypass and service disruption capabilities that attackers can exploit. Organizations should also conduct thorough security assessments of their Tomcat deployments to identify any custom applications that may be vulnerable to similar authorization bypass scenarios.