CVE-2004-0131 in Radius
Summary
by MITRE
The rad_print_request function in logger.c for GNU Radius daemon (radiusd) before 1.2 allows remote atackers to cause a denial of service (crash) via a UDP packet with an Acct-Status-Type attribute without a value and no Acct-Session-Id attribute, which causes a null dereference.
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Analysis
by VulDB Data Team • 12/15/2024
The vulnerability identified as CVE-2004-0131 affects the GNU Radius daemon version 1.1 and earlier, specifically within the rad_print_request function located in the logger.c file. This issue represents a classic null pointer dereference flaw that can be exploited to trigger a denial of service condition. The GNU Radius daemon serves as a network access control server implementing the RADIUS protocol, which is widely used for authentication, authorization, and accounting services in network infrastructure. The vulnerability manifests when processing incoming UDP packets that contain specific attribute configurations, making it particularly dangerous in network environments where RADIUS services are critical for access control.
The technical flaw occurs when the rad_print_request function attempts to process a UDP packet containing an Acct-Status-Type attribute without a corresponding value, combined with the absence of an Acct-Session-Id attribute. This specific combination of missing attributes creates a scenario where the function fails to properly validate input data before attempting to dereference a null pointer. The function's inability to handle this particular attribute configuration results in an immediate crash of the radiusd daemon process, effectively rendering the authentication service unavailable to legitimate users. This type of vulnerability falls under CWE-476 which specifically addresses NULL pointer dereference conditions, and represents a fundamental flaw in input validation and error handling within the network service implementation.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be exploited by remote attackers without requiring authentication or special privileges. The denial of service condition affects the availability aspect of the CIA triad, potentially compromising network access control mechanisms that depend on the RADIUS service. In enterprise environments where network access is controlled through RADIUS authentication, this vulnerability could enable attackers to gain unauthorized access to network resources by disrupting legitimate authentication processes. The attack vector through UDP packets makes it particularly challenging to defend against since it can be launched from any network location capable of sending UDP traffic to the vulnerable daemon.
Mitigation strategies for CVE-2004-0131 include immediate patching of the GNU Radius daemon to version 1.2 or later, where the vulnerability has been addressed through proper input validation and null pointer checks. Network administrators should implement firewall rules to restrict access to the RADIUS service ports, particularly when the service is not essential for the local network environment. Additionally, monitoring systems should be configured to detect unusual patterns of RADIUS service disruptions that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper input validation and defensive programming practices, aligning with ATT&CK technique T1499.004 which covers network disruption attacks. Organizations should also consider implementing redundant authentication mechanisms and ensuring that all network services undergo regular security assessments to identify similar input validation flaws that could lead to similar denial of service conditions.