CVE-2003-0967 in FreeRADIUS
Summary
by MITRE
rad_decode in FreeRADIUS 0.9.2 and earlier allows remote attackers to cause a denial of service (crash) via a short RADIUS string attribute with a tag, which causes memcpy to be called with a -1 length argument, as demonstrated using the Tunnel-Password attribute.
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Analysis
by VulDB Data Team • 10/01/2024
The vulnerability identified as CVE-2003-0967 represents a critical buffer overflow condition within the FreeRADIUS server software version 0.9.2 and earlier. This flaw exists in the rad_decode function which processes RADIUS string attributes during authentication and accounting operations. The vulnerability specifically manifests when processing tunnel attributes that contain tags, creating a scenario where the system attempts to execute a memcpy operation with a negative length parameter of -1. This fundamental error in input validation and parameter handling creates an exploitable condition that can be leveraged by remote attackers to disrupt service availability.
The technical implementation of this vulnerability stems from inadequate bounds checking within the RADIUS packet processing pipeline. When a maliciously crafted RADIUS packet contains a Tunnel-Password attribute with a malformed tag structure, the rad_decode function fails to properly validate the attribute length before attempting memory operations. This failure directly violates the principles of secure coding practices and represents a classic case of improper input validation. The negative length argument passed to memcpy results in undefined behavior that typically manifests as program termination or segmentation fault, effectively causing the FreeRADIUS service to crash and become unavailable to legitimate users.
From an operational perspective, this vulnerability presents a significant denial of service threat to network infrastructure relying on FreeRADIUS for authentication services. Organizations implementing RADIUS-based authentication for wireless networks, VPN access, or network device management face potential service disruption when attackers exploit this condition. The attack vector requires only the ability to send specially crafted RADIUS packets to the target server, making it particularly dangerous as it can be executed remotely without authentication. The impact extends beyond simple service interruption to potentially compromising network access control and user productivity, especially in environments where continuous authentication services are critical.
The vulnerability aligns with CWE-129, which addresses improper validation of length parameters, and demonstrates characteristics consistent with ATT&CK technique T1499.004 for network denial of service attacks. Organizations should implement immediate mitigations including upgrading to FreeRADIUS version 1.0.0 or later where this issue has been resolved through proper input validation and length parameter checking. Network segmentation and access control measures can provide additional defense in depth, while monitoring systems should be configured to detect unusual patterns of RADIUS packet processing failures. The fix implemented in subsequent versions involves rigorous validation of attribute lengths before memory operations are performed, ensuring that negative values cannot be passed to memory manipulation functions and preventing the exploitation of this class of buffer overflow vulnerability.