CVE-2011-2730 in Spring Framework
Summary
by MITRE
VMware SpringSource Spring Framework before 2.5.6.SEC03, 2.5.7.SR023, and 3.x before 3.0.6, when a container supports Expression Language (EL), evaluates EL expressions in tags twice, which allows remote attackers to obtain sensitive information via a (1) name attribute in a (a) spring:hasBindErrors tag; (2) path attribute in a (b) spring:bind or (c) spring:nestedpath tag; (3) arguments, (4) code, (5) text, (6) var, (7) scope, or (8) message attribute in a (d) spring:message or (e) spring:theme tag; or (9) var, (10) scope, or (11) value attribute in a (f) spring:transform tag, aka "Expression Language Injection."
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Analysis
by VulDB Data Team • 12/20/2021
The vulnerability identified as CVE-2011-2730 represents a critical expression language injection flaw within the VMware SpringSource Spring Framework that affects multiple versions prior to specific security patches. This vulnerability specifically targets applications that utilize Expression Language (EL) evaluation within their web containers, creating a scenario where malicious actors can exploit the framework's handling of EL expressions to extract sensitive information from the application environment. The flaw stems from the improper evaluation of EL expressions in various Spring tags, where the same expressions are processed twice, creating opportunities for attackers to manipulate input parameters and gain unauthorized access to system data. The vulnerability is particularly concerning as it affects widely used Spring Framework versions and operates at the core of web application security within enterprise environments.
The technical implementation of this vulnerability occurs through the improper handling of attribute values within Spring framework tags that support EL evaluation. When the framework processes tags such as spring:hasBindErrors, spring:bind, spring:nestedpath, spring:message, spring:theme, and spring:transform, it evaluates the specified attributes containing EL expressions twice instead of once. This double evaluation creates a condition where attacker-controlled input in attributes like name, path, arguments, code, text, var, scope, message, and value can be manipulated to execute unintended expressions. The CWE-94 weakness classification applies here as this represents an improper control of generation of code, specifically allowing for expression language injection through web application components. The vulnerability operates under the ATT&CK technique T1213.002 for data from information repositories and T1068 for exploit for privilege escalation, as attackers can leverage this to extract sensitive information and potentially gain deeper system access.
The operational impact of CVE-2011-2730 extends beyond simple information disclosure to potentially enable more sophisticated attacks within affected applications. Remote attackers can exploit this vulnerability to extract configuration details, database connection strings, user credentials, and other sensitive data that might be embedded within the application's EL expressions. The vulnerability affects applications deployed on containers that support EL evaluation, making it particularly dangerous in enterprise environments where Spring Framework is extensively used for web application development. Organizations running affected versions of Spring Framework face significant risk of data breaches and unauthorized access to critical system information. The vulnerability's impact is amplified by the fact that it can be exploited through multiple tag types and attribute combinations, providing attackers with multiple vectors for information extraction and potential privilege escalation.
Mitigation strategies for CVE-2011-2730 focus on immediate version upgrades to patched releases of the Spring Framework, specifically targeting versions 2.5.6.SEC03, 2.5.7.SR023, and 3.0.6 or later. Organizations should implement comprehensive patch management procedures to ensure all affected systems receive the necessary updates promptly. Additionally, administrators should consider disabling EL evaluation for user-controllable input parameters when possible, implementing strict input validation and sanitization measures for all attributes that support EL expressions. The implementation of web application firewalls and security monitoring systems can help detect and prevent exploitation attempts. Organizations should also conduct thorough security assessments of their applications to identify and remediate any custom code that might be vulnerable to similar expression language injection patterns. Regular security training for development teams on secure coding practices and proper handling of user input can prevent similar vulnerabilities from being introduced in future application deployments, aligning with security best practices outlined in OWASP Top 10 and NIST cybersecurity frameworks.