CVE-2012-0993 in ZenPhoto
Summary
by MITRE
Eval injection vulnerability in zp-core/zp-extensions/viewer_size_image.php in ZENphoto 1.4.2, when the viewer_size_image plugin is enabled, allows remote attackers to execute arbitrary PHP code via the viewer_size_image_saved cookie.
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Analysis
by VulDB Data Team • 11/30/2021
The CVE-2012-0993 vulnerability represents a critical server-side code injection flaw within the ZENphoto content management system version 1.4.2. This vulnerability specifically targets the viewer_size_image plugin, which is designed to handle image viewing functionality within the system. The flaw exists in the zp-core/zp-extensions/viewer_size_image.php file where user-supplied input from the viewer_size_image_saved cookie is improperly processed without adequate sanitization or validation. This creates an exploitable condition that allows remote attackers to inject and execute arbitrary PHP code on the affected server.
The technical implementation of this vulnerability stems from insufficient input validation and improper output encoding within the cookie handling mechanism. When the viewer_size_image plugin is enabled, it processes the viewer_size_image_saved cookie value directly in the PHP execution context without proper sanitization measures. This allows attackers to craft malicious cookie values containing PHP code that gets executed when the plugin processes the cookie data. The vulnerability falls under the CWE-94 category of "Improper Control of Generation of Code" and specifically aligns with CWE-74 "Improper Neutralization of Special Elements in Output Used by a Downstream Component." The attack vector operates through the HTTP cookie mechanism, making it accessible to remote adversaries who can manipulate the cookie content to achieve code execution.
The operational impact of this vulnerability is severe and multifaceted, potentially enabling full system compromise for attackers who successfully exploit it. Once executed, the injected PHP code can perform arbitrary operations including but not limited to reading or modifying system files, executing shell commands, accessing databases, and establishing persistent backdoors. The vulnerability affects the entire ZENphoto installation as long as the viewer_size_image plugin remains enabled, making it particularly dangerous for web applications that rely on this plugin for image management functionality. This type of vulnerability directly maps to ATT&CK technique T1190 "Exploit Public-Facing Application" and can facilitate further lateral movement within compromised networks through the execution of additional malicious payloads. The remote nature of the attack means that exploitation does not require physical access to the system, making it particularly concerning for web applications accessible over the internet.
Mitigation strategies for CVE-2012-0993 should focus on immediate remediation and long-term architectural improvements to prevent similar vulnerabilities. The primary and most effective solution involves upgrading to a patched version of ZENphoto that addresses this specific code injection vulnerability. Organizations should also implement proper input validation and output encoding mechanisms for all cookie data processing, ensuring that any user-supplied input is thoroughly sanitized before being processed by the application. Network-level defenses including web application firewalls and intrusion detection systems can provide additional protection layers, though they should not be relied upon as the sole mitigation. Security hardening practices such as disabling unnecessary plugins, implementing proper cookie security attributes including HttpOnly and Secure flags, and conducting regular security audits of application code should be implemented. The vulnerability demonstrates the critical importance of following secure coding practices and adhering to the principle of least privilege in web application development, particularly when handling user-supplied data in server-side execution contexts.