CVE-2013-2220 in Radius Extension
Summary
by MITRE
Buffer overflow in the radius_get_vendor_attr function in the Radius extension before 1.2.7 for PHP allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a large Vendor Specific Attributes (VSA) length value.
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Analysis
by VulDB Data Team • 01/04/2022
The vulnerability identified as CVE-2013-2220 represents a critical buffer overflow flaw within the radius_get_vendor_attr function of the Radius extension for PHP. This issue affects versions prior to 1.2.7 and demonstrates a classic security weakness that can be exploited by remote attackers to compromise system integrity. The vulnerability specifically targets the handling of Vendor Specific Attributes within the RADIUS protocol implementation, creating a pathway for malicious actors to manipulate memory allocation processes.
The technical flaw manifests when the radius_get_vendor_attr function processes Vendor Specific Attributes with excessively large length values. This function fails to properly validate input parameters, particularly the length field of VSA elements, allowing attackers to supply malformed data that exceeds the allocated buffer boundaries. The insufficient bounds checking creates an exploitable condition where memory corruption occurs during the processing of legitimate RADIUS packets containing oversized vendor-specific attributes. This vulnerability directly maps to CWE-121, which describes stack-based buffer overflow conditions, and potentially CWE-787, representing out-of-bounds write conditions that can lead to arbitrary code execution.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to potentially enable remote code execution on affected systems. When exploited successfully, attackers can cause the PHP process to crash or, more critically, inject and execute malicious code within the context of the web server process. This represents a significant escalation from basic denial of service to full system compromise, particularly in environments where the Radius extension is used for authentication purposes. The vulnerability affects systems that rely on PHP-based RADIUS authentication mechanisms, potentially compromising network access controls and user authentication processes.
Systems utilizing PHP versions with the vulnerable Radius extension are at risk when processing RADIUS packets containing maliciously crafted Vendor Specific Attributes. The attack vector requires remote access to the affected PHP application, making it particularly dangerous in web-facing environments. Organizations should consider the potential for privilege escalation and data compromise when evaluating the impact of this vulnerability. The vulnerability's exploitation potential aligns with ATT&CK technique T1203, which covers legitimate credentials and privilege escalation through network protocol manipulation.
Mitigation strategies for CVE-2013-2220 primarily focus on immediate patching of the affected Radius extension to version 1.2.7 or later, which includes proper input validation and buffer boundary checks. System administrators should also implement network-level monitoring to detect unusual RADIUS packet patterns and implement rate limiting for authentication requests. Additionally, organizations should consider restricting direct network access to PHP applications that utilize the Radius extension and employ input sanitization measures to validate all RADIUS attribute data before processing. The implementation of intrusion detection systems capable of identifying malformed RADIUS packets can provide additional defense-in-depth measures against exploitation attempts.