CVE-2012-2969 in Resin
Summary
by MITRE
Caucho Quercus, as distributed in Resin before 4.0.29, allows remote attackers to bypass intended restrictions on filename extensions for created files via a %00 sequence in a pathname within an HTTP request.
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Analysis
by VulDB Data Team • 08/10/2024
The vulnerability identified as CVE-2012-2969 affects Caucho Quercus, a php implementation that is part of the Resin application server ecosystem. This issue represents a critical security flaw in how the system handles file path validation during HTTP request processing. The vulnerability specifically targets the filename extension restriction mechanisms that are typically implemented to prevent unauthorized file creation or execution within web applications. When an attacker crafts a malicious HTTP request containing a null byte sequence %00 within a pathname, the system fails to properly validate the file path, allowing unauthorized file operations that should have been prevented by the intended security restrictions.
The technical flaw stems from improper input sanitization and path validation within the Quercus runtime environment. The %00 sequence, which represents a null byte in URL encoding, is commonly used in various injection attacks to terminate strings prematurely. In this context, the null byte sequence allows attackers to bypass the intended file extension validation by terminating the path string at an arbitrary point, effectively circumventing the security controls that would normally prevent creation of files with restricted extensions. This type of vulnerability falls under the CWE-170 category of improper null termination, which is classified as a weakness that can lead to various injection attacks and privilege escalation scenarios.
The operational impact of this vulnerability is significant for organizations using Resin versions prior to 4.0.29, as it provides remote attackers with the capability to create arbitrary files with potentially malicious extensions in directories that should be protected. This could enable attackers to upload web shells, backdoors, or other malicious payloads that could compromise the entire web application server. The vulnerability essentially undermines the fundamental security principle of least privilege by allowing unauthorized file creation operations that could lead to complete system compromise. Attackers could potentially leverage this vulnerability to execute arbitrary code on the server, escalate privileges, or establish persistent access to the affected system.
Organizations should immediately upgrade to Resin version 4.0.29 or later, which contains the necessary patches to address this vulnerability. Additionally, implementing proper input validation at multiple layers of the application stack can provide defense-in-depth protection. Network segmentation and web application firewalls should be configured to monitor for suspicious URL encoding patterns, particularly those containing null byte sequences. The vulnerability aligns with several ATT&CK techniques including T1190 for exploit public-facing application and T1059 for command and scripting interpreter, as attackers could potentially use this vulnerability to establish persistent access and execute malicious commands on the compromised system. Security monitoring should focus on detecting unusual file creation patterns and suspicious HTTP requests containing encoded null sequences that could indicate exploitation attempts.