CVE-2006-0764 in Traffic Anomaly Detector Module
Summary
by MITRE
The Authentication, Authorization, and Accounting (AAA) capability in versions 5.0(1) and 5.0(3) of the software used by multiple Cisco Anomaly Detection and Mitigation products, when running with an incomplete TACACS+ configuration without a "tacacs-server host" command, allows remote attackers to bypass authentication and gain privileges, aka Bug ID CSCsd21455.
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Analysis
by VulDB Data Team • 08/05/2017
The vulnerability described in CVE-2006-0764 represents a critical authentication flaw within Cisco's Anomaly Detection and Mitigation products that specifically affects versions 5.0(1) and 5.0(3) of the affected software. This issue resides within the Authentication, Authorization, and Accounting (AAA) framework which serves as the foundational security mechanism for controlling access to network devices and services. The flaw manifests when the system operates with an incomplete TACACS+ configuration where the crucial "tacacs-server host" command has not been properly implemented, creating a dangerous security gap that can be exploited by remote adversaries.
The technical implementation of this vulnerability stems from the software's failure to properly validate authentication requests when TACACS+ servers are not explicitly configured in the system. When the "tacacs-server host" command is missing from the configuration, the AAA subsystem does not enforce proper authentication checks, allowing unauthorized users to bypass the authentication process entirely. This represents a fundamental breakdown in the security architecture where the system defaults to a permissive state rather than a secure default when critical configuration elements are absent. The vulnerability is classified as a misconfiguration issue that can be exploited through remote network access without requiring any special privileges or physical access to the device.
The operational impact of this vulnerability is severe as it allows remote attackers to completely bypass the authentication mechanisms that are designed to protect sensitive network management functions. An attacker who successfully exploits this vulnerability can gain unauthorized administrative access to the affected Cisco products, potentially leading to full system compromise, data exfiltration, network disruption, or use of the compromised device as a pivot point for further attacks within the network infrastructure. The vulnerability affects multiple Cisco Anomaly Detection and Mitigation products, amplifying the potential impact across various network security solutions. This issue directly violates the principle of least privilege and can result in unauthorized access to critical network monitoring and threat mitigation capabilities.
Mitigation strategies for this vulnerability require immediate implementation of proper TACACS+ server configuration including the mandatory "tacacs-server host" command to define authoritative authentication servers. Network administrators should conduct comprehensive audits of all affected devices to ensure complete AAA configuration and implement proper security monitoring to detect unauthorized configuration changes. The vulnerability aligns with CWE-254, which addresses security weaknesses related to incomplete or inconsistent information about authentication and authorization, and can be mapped to ATT&CK technique T1078 for valid accounts and T1566 for phishing attacks that may exploit such misconfigurations. Organizations should also implement network segmentation, access control lists, and regular security assessments to reduce the attack surface and prevent exploitation of similar configuration weaknesses in other network infrastructure components.