CVE-2002-0159 in Secure Access Control Server
Summary
by MITRE
Format string vulnerability in the administration function in Cisco Secure Access Control Server (ACS) for Windows, 2.6.x and earlier and 3.x through 3.01 (build 40), allows remote attackers to crash the CSADMIN module only (denial of service of administration function) or execute arbitrary code via format strings in the URL to port 2002.
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Analysis
by VulDB Data Team • 09/22/2025
The vulnerability identified as CVE-2002-0159 represents a critical format string flaw within the Cisco Secure Access Control Server (ACS) for Windows implementation. This issue affects versions 2.6.x and earlier, as well as 3.x through 3.01 build 40, specifically targeting the administrative function of the system. The vulnerability manifests in the CSADMIN module which operates on port 2002, making it accessible to remote attackers who can exploit this weakness through crafted URL requests. The format string vulnerability occurs when the application fails to properly validate and sanitize user-supplied input before using it in printf or similar formatting functions, allowing attackers to manipulate the format string arguments.
The technical exploitation of this vulnerability enables attackers to perform either denial of service attacks by crashing the CSADMIN module or achieve arbitrary code execution within the context of the affected system. This represents a severe security risk as the administrative interface typically operates with elevated privileges and controls critical access control functions. The flaw allows attackers to inject malicious format specifiers that can lead to stack corruption, information disclosure, or code execution. According to CWE classification, this vulnerability maps to CWE-134 which specifically addresses format string vulnerabilities where format strings are constructed from user-supplied data without proper validation.
The operational impact of this vulnerability extends beyond simple service disruption as it compromises the integrity of the access control system. When attackers successfully exploit this flaw, they can potentially gain unauthorized administrative access to the Cisco ACS system, undermining the entire security framework that the platform is designed to provide. The vulnerability affects the core administrative functionality, making it particularly dangerous for organizations that rely on Cisco ACS for network access control and authentication services. The remote nature of the attack means that adversaries can exploit this without requiring physical access or local network presence, making it an attractive target for malicious actors seeking to compromise enterprise security infrastructure.
Organizations should implement immediate mitigations including network segmentation to restrict access to port 2002, applying the latest security patches from Cisco, and implementing network monitoring to detect suspicious format string exploitation attempts. The vulnerability demonstrates the importance of input validation in security-critical applications and highlights the need for proper secure coding practices. From an ATT&CK framework perspective, this vulnerability aligns with techniques involving remote code execution and privilege escalation, potentially enabling adversaries to move laterally within networks or maintain persistent access through compromised administrative interfaces. The incident underscores the critical importance of regular security assessments and vulnerability management programs to identify and remediate such flaws before they can be exploited by threat actors.