CVE-2011-4343 in MyFaces Core
Summary
by MITRE
Information disclosure vulnerability in Apache MyFaces Core 2.0.1 through 2.0.10 and 2.1.0 through 2.1.4 allows remote attackers to inject EL expressions via crafted parameters.
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Analysis
by VulDB Data Team • 01/07/2021
The vulnerability identified as CVE-2011-4343 represents a critical information disclosure flaw within Apache MyFaces Core framework versions ranging from 2.0.1 through 2.0.10 and 2.1.0 through 2.1.4. This vulnerability stems from insufficient input validation and sanitization mechanisms that fail to properly handle crafted parameters containing expression language expressions. The flaw exists in the component parameter processing logic where user-supplied input is directly incorporated into the expression evaluation context without adequate sanitization measures.
The technical implementation of this vulnerability exploits the framework's use of Unified Expression Language (UEL) for processing component attributes and parameters. When maliciously crafted parameters containing EL expressions are submitted to affected applications, the framework processes these expressions within the context of the current request, potentially allowing attackers to access sensitive information through expression evaluation. The vulnerability specifically targets the component parameter handling mechanism where parameter values are not properly escaped or validated before being processed as expression language constructs. This allows attackers to inject expressions that can access application context, session data, and other sensitive information that would normally be protected from direct user access.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially enable more sophisticated attacks including remote code execution in certain configurations. Attackers can leverage this vulnerability to extract session identifiers, application configuration details, database connection strings, and other sensitive application data. The vulnerability affects web applications built on the Apache MyFaces framework where user input is processed through component parameters, making it particularly dangerous in enterprise environments where sensitive data is routinely handled. The remote nature of this attack means that exploitation can occur from any location without requiring physical access to the target system.
This vulnerability maps to CWE-20: Improper Input Validation and CWE-94: Improper Control of Generation of Code, as it involves the improper handling of user-supplied input that leads to code generation through expression evaluation. From an ATT&CK framework perspective, this vulnerability aligns with T1059.001: Command and Scripting Interpreter - PowerShell and T1566: Phishing, as attackers can use the information disclosure to gather intelligence for more targeted attacks. The vulnerability also relates to T1068: Exploitation for Privilege Escalation when combined with other exploitation techniques. Organizations should implement immediate mitigations including upgrading to patched versions of Apache MyFaces Core, implementing input validation at the application level, and deploying web application firewalls to filter suspicious parameter values. Additionally, comprehensive logging and monitoring should be enabled to detect potential exploitation attempts, and security reviews should be conducted to ensure proper parameter handling throughout the application codebase.