CVE-2015-6300 in Secure Access Control Server
Summary
by MITRE
Cisco Secure Access Control Server (ACS) Solution Engine 5.7(0.15) allows remote authenticated users to cause a denial of service (SSH screen process crash) via crafted (1) CLI or (2) GUI commands, aka Bug ID CSCuw24694.
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Analysis
by VulDB Data Team • 06/18/2022
The vulnerability identified as CVE-2015-6300 affects Cisco Secure Access Control Server Solution Engine version 5.7(0.15) and represents a significant denial of service weakness that can be exploited by remotely authenticated attackers. This vulnerability specifically targets the SSH screen process within the ACS solution engine, creating a critical operational risk for organizations relying on Cisco's access control infrastructure. The flaw manifests when authenticated users submit carefully crafted command line interface or graphical user interface commands that trigger an unexpected system crash, effectively disrupting legitimate network access services and user authentication processes.
The technical implementation of this vulnerability stems from insufficient input validation and error handling within the SSH screen process of the Cisco ACS solution engine. When legitimate authenticated users execute malformed CLI or GUI commands, the system fails to properly sanitize or validate the input parameters, leading to memory corruption or unexpected state transitions that ultimately cause the SSH screen process to terminate abruptly. This behavior aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-122, which covers buffer overflow vulnerabilities that can lead to process termination. The vulnerability specifically impacts the authentication and authorization functions that rely on SSH connectivity for administrative access to the ACS solution engine, making it particularly dangerous for network security operations.
The operational impact of CVE-2015-6300 extends beyond simple service disruption to create potential security gaps in network access control. When the SSH screen process crashes, administrators lose access to critical configuration and monitoring capabilities, potentially leaving the network vulnerable during the recovery period. This denial of service condition affects not only the immediate administrative access but also impacts the broader authentication infrastructure that relies on the ACS solution engine for user validation. The vulnerability creates a window of opportunity for malicious actors to exploit the service interruption, potentially leading to unauthorized access attempts or extended periods of reduced network security posture. Organizations may experience cascading effects as network users lose access to authentication services, with potential impacts on productivity and security monitoring capabilities that can persist until the affected service is manually restarted or the system is rebooted.
Mitigation strategies for CVE-2015-6300 should focus on immediate patch management and operational hardening measures. Cisco has released security updates addressing this vulnerability, and organizations should prioritize applying the relevant software patches to prevent exploitation. Network administrators should implement monitoring solutions to detect unusual SSH process termination patterns and establish automated alerting for service disruptions. Access controls should be tightened to limit the number of authenticated users with administrative privileges, reducing the attack surface for potential exploitation. The vulnerability's characteristics align with ATT&CK technique T1499, which covers network disruption attacks, and T1566, which addresses credential harvesting through various attack vectors. Organizations should also consider implementing network segmentation to isolate critical access control infrastructure and maintain detailed audit logs of administrative activities to detect potential exploitation attempts. Regular security assessments and vulnerability scanning should be conducted to identify similar input validation weaknesses in other network infrastructure components, ensuring comprehensive protection against similar threats.