CVE-2016-2042 in phpMyAdmin
Summary
by MITRE
phpMyAdmin 4.4.x before 4.4.15.3 and 4.5.x before 4.5.4 allows remote attackers to obtain sensitive information via a crafted request to (1) libraries/phpseclib/Crypt/AES.php or (2) libraries/phpseclib/Crypt/Rijndael.php, which reveals the full path in an error message.
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Analysis
by VulDB Data Team • 07/08/2022
The vulnerability CVE-2016-2042 affects phpMyAdmin versions 4.4.x prior to 4.4.15.3 and 4.5.x prior to 4.5.4, representing a critical information disclosure flaw that exposes system paths through error messages. This vulnerability resides within the phpseclib cryptographic library components, specifically in the Crypt/AES.php and Crypt/Rijndael.php files, which are integral parts of phpMyAdmin's database management functionality. The flaw manifests when remote attackers send specially crafted requests that trigger error conditions within these cryptographic libraries, causing the application to reveal the full server path in error messages. This information disclosure vulnerability directly violates security principles by providing attackers with potentially sensitive system information that could aid in further exploitation attempts.
The technical mechanism behind this vulnerability involves improper error handling within the phpseclib library components that phpMyAdmin utilizes for cryptographic operations. When malformed requests are processed by the AES or Rijndael encryption modules, the libraries fail to sanitize error messages properly, resulting in the exposure of absolute file paths on the server. This occurs because the error handling code does not adequately filter or escape path information before displaying it to users, creating a direct path disclosure scenario. The vulnerability is classified under CWE-209, which specifically addresses "Information Exposure Through an Error Message," and represents a classic case of insufficient error handling that exposes system-level information to unauthorized users. The affected phpseclib components are widely used cryptographic libraries that implement the Advanced Encryption Standard and Rijndael algorithms, making this vulnerability particularly concerning as it affects core encryption functionality.
From an operational impact perspective, this vulnerability significantly increases the attack surface for phpMyAdmin installations by providing attackers with detailed system path information that can be used for subsequent exploitation attempts. The disclosed paths may reveal directory structures, file locations, and potentially sensitive configuration details that could aid in crafting more sophisticated attacks. Attackers could leverage this information to perform path traversal attacks, identify specific file versions, or map the server environment to plan further infiltration strategies. The vulnerability also aligns with ATT&CK technique T1083, which covers "File and Directory Discovery," as the information disclosure directly reveals file system structures. Additionally, this flaw could contribute to broader reconnaissance efforts that might lead to privilege escalation or data exfiltration, as the exposed paths could reveal other potentially vulnerable components within the system architecture.
The recommended mitigation strategies for CVE-2016-2042 involve immediate patching of phpMyAdmin installations to versions 4.4.15.3 or 4.5.4, which contain the necessary fixes for the error handling issues in the affected cryptographic libraries. System administrators should also implement proper error handling configurations that prevent detailed error messages from being displayed to end users, ensuring that all error outputs are sanitized and generic. Organizations should consider implementing web application firewalls that can detect and block malicious requests targeting these specific library components, as well as monitoring for unusual access patterns that might indicate exploitation attempts. Additionally, regular security assessments should be conducted to identify other potential information disclosure vulnerabilities within the application stack, and proper logging mechanisms should be established to track error conditions and access attempts to cryptographic library components. The fix addresses the root cause by ensuring that error messages properly sanitize path information and do not expose system-level details to unauthorized users, thereby maintaining the principle of least privilege and reducing the attack surface for potential exploitation attempts.