CVE-2004-0961 in FreeRADIUS
Summary
by MITRE
Memory leak in FreeRADIUS before 1.0.1 allows remote attackers to cause a denial of service (memory exhaustion) via a series of Access-Request packets with (1) Ascend-Send-Secret, (2) Ascend-Recv-Secret, or (3) Tunnel-Password attributes.
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Analysis
by VulDB Data Team • 12/16/2024
The vulnerability identified as CVE-2004-0961 represents a critical memory management flaw in FreeRADIUS versions prior to 1.0.1 that enables remote attackers to execute denial of service attacks through carefully crafted Access-Request packets. This memory leak vulnerability specifically targets the handling of three particular attributes: Ascend-Send-Secret, Ascend-Recv-Secret, and Tunnel-Password, which are commonly used in network access control and authentication protocols. The flaw stems from inadequate memory allocation and deallocation mechanisms within the radius server implementation, where allocated memory blocks are not properly released after processing these specific attribute types.
The technical exploitation of this vulnerability occurs when remote attackers send a sequence of Access-Request packets containing the targeted attributes, causing the FreeRADIUS server to continuously allocate memory without proper cleanup. Each packet processing cycle consumes additional memory resources, leading to progressive memory exhaustion over time. The vulnerability manifests as a gradual degradation of system performance followed by complete service unavailability when memory resources are depleted. This type of memory leak aligns with CWE-401, which specifically addresses improper deallocation of memory, and represents a classic example of resource exhaustion attacks that fall under the ATT&CK technique T1499.004 for network denial of service.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the entire network authentication infrastructure that relies on FreeRADIUS for access control. Organizations using affected versions of FreeRADIUS face significant risk of unauthorized network access disruption, particularly in environments where continuous authentication services are critical for network operations. The vulnerability affects systems that implement RADIUS protocol authentication, which is widely used in wireless networks, VPN services, and enterprise network access control. Attackers can leverage this flaw to systematically consume available memory resources, making it particularly dangerous in high-traffic environments where authentication requests are frequent.
Mitigation strategies for CVE-2004-0961 primarily focus on upgrading to FreeRADIUS version 1.0.1 or later, where the memory leak has been addressed through proper memory management practices and enhanced resource cleanup mechanisms. Network administrators should also implement monitoring solutions to detect unusual memory consumption patterns and establish automated alerting systems that can identify potential exploitation attempts. Additionally, implementing rate limiting and connection throttling mechanisms can help reduce the impact of such attacks by limiting the number of malicious packets that can be processed within a given timeframe. The fix implemented in version 1.0.1 demonstrates proper adherence to secure coding practices and memory management standards, ensuring that allocated resources are properly released after attribute processing to prevent future occurrences of similar vulnerabilities.