CVE-2007-0906 in PHP
Summary
by MITRE
Multiple buffer overflows in PHP before 5.2.1 allow attackers to cause a denial of service and possibly execute arbitrary code via unspecified vectors in the (1) session, (2) zip, (3) imap, and (4) sqlite extensions; (5) stream filters; and the (6) str_replace, (7) mail, (8) ibase_delete_user, (9) ibase_add_user, and (10) ibase_modify_user functions. NOTE: vector 6 might actually be an integer overflow (CVE-2007-1885). NOTE: as of 20070411, vector (3) might involve the imap_mail_compose function (CVE-2007-1825).
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Analysis
by VulDB Data Team • 08/10/2022
The vulnerability identified as CVE-2007-0906 represents a critical security flaw affecting PHP versions prior to 5.2.1, encompassing multiple buffer overflow conditions across various PHP extensions and functions. This vulnerability classifies under CWE-121, which describes stack-based buffer overflow conditions, and affects the core functionality of PHP applications that utilize session management, zip file processing, imap communication, and sqlite database operations. The flaw manifests through multiple attack vectors including session handling, zip archive processing, imap mail composition, and sqlite database interactions, creating an extensive attack surface for malicious actors seeking to exploit these weaknesses.
The technical implementation of this vulnerability stems from insufficient bounds checking in several PHP extensions and functions, allowing attackers to write beyond allocated memory buffers. When PHP processes user-supplied input through the affected session, zip, imap, and sqlite extensions, the lack of proper input validation enables memory corruption that can result in arbitrary code execution or system crashes. The specific functions impacted include str_replace operations, mail handling, and interbase user management functions, each presenting unique pathways for exploitation. The vulnerability's complexity increases with the number of affected components, as each extension may have different memory handling characteristics and buffer management strategies that can be individually targeted.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable complete system compromise. Attackers can leverage these buffer overflows to execute arbitrary code on vulnerable systems, effectively gaining unauthorized access to server resources and potentially escalating privileges. The vulnerability's presence in core PHP functions like session management means that any web application utilizing PHP sessions could be compromised, while the imap_mail_compose function exposure creates additional risks for email processing applications. The integer overflow designation for vector 6 (CVE-2007-1885) indicates that some of these vulnerabilities may involve different exploitation mechanisms, though the core issue remains memory corruption through improper input handling. The inclusion of stream filters in this vulnerability further expands the attack surface, as these components are frequently used in data processing pipelines within PHP applications.
Mitigation strategies for CVE-2007-0906 require immediate patching of affected PHP installations to version 5.2.1 or later, which contains the necessary security fixes for all identified buffer overflow conditions. System administrators should implement comprehensive input validation across all PHP applications to reduce the impact of potential exploitation attempts, particularly in areas involving user-supplied data processing. Network-based mitigations including firewall rules and intrusion detection systems can help prevent exploitation attempts by monitoring for suspicious patterns in network traffic related to these vulnerable functions. The ATT&CK framework categorizes this vulnerability under T1190 for exploit public-facing application and T1059 for command and scripting interpreter, indicating that exploitation typically occurs through web application interfaces. Organizations should also implement regular security assessments and vulnerability scanning to identify any remaining instances of older PHP versions that may still be in use within their infrastructure. The remediation process must include thorough testing of patched systems to ensure that security updates do not introduce compatibility issues with existing applications while maintaining the integrity of the security fixes.