CVE-2007-0905 in PHP
Summary
by MITRE
PHP before 5.2.1 allows attackers to bypass safe_mode and open_basedir restrictions via unspecified vectors in the session extension. NOTE: it is possible that this issue is a duplicate of CVE-2006-6383.
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Analysis
by VulDB Data Team • 03/15/2021
The vulnerability described in CVE-2007-0905 represents a critical security flaw in PHP versions prior to 5.2.1 that specifically targets the session extension component. This issue allows malicious actors to circumvent fundamental security mechanisms including safe_mode and open_basedir restrictions that are designed to limit file access and prevent unauthorized operations within web applications. The vulnerability stems from unspecified vectors within the session handling functionality, making it particularly challenging to predict and prevent without comprehensive understanding of the underlying implementation details.
The technical flaw manifests through the session extension's improper handling of certain operations that should be restricted by PHP's security policies. When PHP operates in safe_mode or with open_basedir restrictions enabled, these mechanisms are intended to prevent scripts from accessing files outside of designated directories and to limit the scope of potentially dangerous operations. However, the vulnerability in the session extension creates pathways through which attackers can bypass these protections, effectively allowing unauthorized file access and execution of operations that should be restricted. This represents a direct violation of the principle of least privilege that forms the foundation of secure application design.
The operational impact of this vulnerability is severe as it enables attackers to escalate privileges and gain unauthorized access to system resources that would normally be protected. An attacker could potentially read sensitive files, execute arbitrary code, or manipulate data within the web application environment. This vulnerability particularly affects web applications that rely on PHP's session management for user authentication and authorization, as it undermines the security boundaries that separate different user sessions and protect against cross-site scripting and other injection attacks. The potential for data breaches, system compromise, and unauthorized access to sensitive information makes this vulnerability particularly dangerous in production environments.
Security professionals should consider this vulnerability in the context of CWE-264, which addresses permissions, privileges, and access controls in software systems. The flaw directly relates to improper access control mechanisms and represents a failure to properly enforce security boundaries within the PHP runtime environment. Organizations should implement immediate mitigations including upgrading to PHP 5.2.1 or later versions where this vulnerability has been addressed. Additionally, administrators should review and properly configure safe_mode and open_basedir settings to ensure that these security mechanisms are functioning correctly. The vulnerability also aligns with ATT&CK techniques related to privilege escalation and persistence, as attackers could use this flaw to maintain long-term access to compromised systems. Regular security assessments and vulnerability scanning should be conducted to identify any remaining instances of older PHP versions that might be susceptible to this and related vulnerabilities.
This vulnerability serves as a reminder of the critical importance of keeping web application frameworks and runtime environments updated with the latest security patches. The fact that this issue may be a duplicate of CVE-2006-6383 indicates that similar vulnerabilities can persist across different versions, emphasizing the need for comprehensive security testing and regular patch management procedures. Organizations should also consider implementing additional security controls such as web application firewalls and runtime monitoring to detect and prevent exploitation attempts that target these types of access control bypass vulnerabilities.