CVE-2008-2441 in Secure ACS
Summary
by MITRE
Cisco Secure ACS 3.x before 3.3(4) Build 12 patch 7, 4.0.x, 4.1.x before 4.1(4) Build 13 Patch 11, and 4.2.x before 4.2(0) Build 124 Patch 4 does not properly handle an EAP Response packet in which the value of the length field exceeds the actual packet length, which allows remote authenticated users to cause a denial of service (CSRadius and CSAuth service crash) or possibly execute arbitrary code via a crafted RADIUS (1) EAP-Response/Identity, (2) EAP-Response/MD5, or (3) EAP-Response/TLS Message Attribute packet.
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Analysis
by VulDB Data Team • 08/16/2019
This vulnerability affects Cisco Secure Access Control Server versions 3.x through 4.2.x, specifically targeting the handling of EAP Response packets within the RADIUS protocol implementation. The flaw resides in the packet validation logic where the system fails to properly verify that the length field in EAP Response packets matches the actual packet content. This improper validation creates a condition where maliciously crafted packets can trigger unexpected behavior in the authentication services.
The technical exploitation occurs when an authenticated remote attacker sends a specially crafted RADIUS EAP-Response packet with a length field that exceeds the actual packet size. This discrepancy causes the CSRadius and CSAuth services to process malformed data structures, leading to memory corruption or buffer overflows. The vulnerability manifests through three specific EAP methods: EAP-Response/Identity, EAP-Response/MD5, and EAP-Response/TLS Message Attribute packets, each representing different authentication phases in the RADIUS protocol implementation.
The operational impact of this vulnerability is significant as it can result in complete service disruption through denial of service conditions where the core authentication services crash and require manual restart. Beyond simple service interruption, the vulnerability presents a potential code execution risk that could allow attackers to gain unauthorized access to the system. This risk escalates when considering that the attacker only needs authenticated access to the system, meaning they can leverage existing credentials to exploit the vulnerability. The services affected include both the central authentication server and the radius services that handle user authentication requests.
The vulnerability maps directly to CWE-129 Input Validation and CWE-787 Out-of-bounds Write, with potential ATT&CK techniques including T1078 Valid Accounts for initial access and T1499 Endpoint Denial of Service for service disruption. Organizations should implement immediate patch management strategies to upgrade to versions 3.3(4) Build 12 patch 7, 4.1(4) Build 13 Patch 11, or 4.2(0) Build 124 Patch 4 respectively. Network segmentation and monitoring of EAP traffic should be implemented to detect anomalous packet patterns. Additionally, implementing proper input validation and bounds checking in the authentication services would prevent similar vulnerabilities from occurring in future deployments.