CVE-2003-0450 in RADIUS Daemon
Summary
by MITRE
Cistron RADIUS daemon (radiusd-cistron) 1.6.6 and earlier allows remote attackers to cause a denial of service and possibly execute arbitrary code via a large value in an NAS-Port attribute, which is interpreted as a negative number and causes a buffer overflow.
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Analysis
by VulDB Data Team • 04/21/2019
The vulnerability identified as CVE-2003-0450 affects the Cistron RADIUS daemon version 1.6.6 and earlier implementations, representing a critical security flaw that exposes systems to both denial of service and potential remote code execution attacks. This vulnerability specifically targets the handling of the NAS-Port attribute within the RADIUS protocol implementation, where the daemon fails to properly validate input values before processing them. The flaw occurs when a malicious attacker sends a RADIUS packet containing an excessively large value in the NAS-Port attribute field, which the software interprets as a negative integer due to improper signedness handling in the parsing logic.
The technical exploitation of this vulnerability stems from a classic buffer overflow condition that arises from the daemon's inadequate input validation mechanisms. When processing the NAS-Port attribute, the software does not properly constrain the range of acceptable values, allowing an attacker to craft packets with values that exceed the expected positive integer boundaries. This overflow condition manifests when the large unsigned value is interpreted by the signed integer processing routines, effectively converting it into a negative number that triggers memory corruption. The resulting buffer overflow can overwrite adjacent memory locations, potentially allowing attackers to manipulate program execution flow and execute arbitrary code on the vulnerable system. This vulnerability maps directly to CWE-121, which describes heap-based buffer overflow conditions, and represents a fundamental failure in input validation and memory management practices.
The operational impact of this vulnerability extends beyond simple service disruption to encompass potential system compromise and unauthorized access to network resources. Organizations relying on Cistron RADIUS daemon for authentication and authorization services face significant risk when exposed to this flaw, as successful exploitation could allow attackers to gain elevated privileges within the network infrastructure. The denial of service aspect of this vulnerability means that legitimate users would be unable to authenticate through the affected RADIUS server, potentially disrupting network access for all authenticated services. Additionally, the remote code execution capability presents a severe threat to network security, as attackers could leverage this vulnerability to establish persistent access to the system and potentially move laterally across the network environment.
Mitigation strategies for CVE-2003-0450 should prioritize immediate patching of affected systems with the vendor-supplied fixes, as no reliable workarounds exist for this particular vulnerability. Organizations should implement network segmentation and access controls to limit exposure of RADIUS servers to untrusted networks, while monitoring for suspicious RADIUS traffic patterns that might indicate exploitation attempts. The implementation of intrusion detection systems capable of identifying malformed RADIUS packets containing unusually large NAS-Port values can provide early warning of potential attacks. Security teams should also conduct comprehensive vulnerability assessments to identify all instances of the affected software across their infrastructure and ensure that proper input validation mechanisms are implemented at network boundaries. From an ATT&CK framework perspective, this vulnerability maps to technique T1190 for exploitation of remote services and T1059 for execution through compromised services, making it a critical target for defensive security measures and incident response planning.