CVE-2002-0769 in ATA
Summary
by MITRE
The web-based configuration interface for the Cisco ATA 186 Analog Telephone Adaptor allows remote attackers to bypass authentication via an HTTP POST request with a single byte, which allows the attackers to (1) obtain the password from the login screen, or (2) reconfigure the adaptor by modifying certain request parameters.
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Analysis
by VulDB Data Team • 09/14/2025
The CVE-2002-0769 vulnerability affects the Cisco ATA 186 Analog Telephone Adaptor, a device that connects analog telephone equipment to IP-based networks. This vulnerability resides in the web-based configuration interface that administrators use to manage the device settings. The flaw represents a critical authentication bypass issue that undermines the security posture of the device and potentially exposes connected telephony infrastructure to unauthorized access. The vulnerability was discovered during the early 2000s when network security practices were still maturing, highlighting the importance of proper input validation in web interfaces.
The technical implementation of this vulnerability stems from inadequate input validation within the HTTP POST request processing mechanism. Attackers can exploit this weakness by sending a specially crafted HTTP POST request containing only a single byte of data, which causes the authentication system to bypass normal validation procedures. This occurs because the device fails to properly validate the request parameters before processing them, allowing malicious input to be interpreted as legitimate authentication data. The vulnerability specifically targets the authentication flow where the system should verify credentials before granting access to configuration parameters. According to CWE standards, this represents a weakness categorized under CWE-287, which deals with improper authentication mechanisms in software systems. The single-byte attack vector demonstrates a fundamental flaw in input sanitization and parameter validation that is common in legacy systems from this era.
The operational impact of this vulnerability is severe and multifaceted, as it provides attackers with complete administrative access to the ATA 186 device. Once authenticated, attackers can perform two primary malicious activities that directly compromise the security and functionality of the telephony infrastructure. The first impact involves credential harvesting, where attackers can extract passwords directly from the login screen, potentially gaining access to other systems that use similar credentials. The second and more dangerous impact allows for complete reconfiguration of the adaptor, enabling attackers to modify dial plans, change routing configurations, redirect calls, and potentially establish backdoor access points for future exploitation. This vulnerability directly maps to ATT&CK technique T1078 which covers valid accounts and T1566 which involves credential harvesting. The attack can be executed remotely without requiring physical access to the device, making it particularly dangerous for organizations that deploy these devices in unsecured locations.
Mitigation strategies for CVE-2002-0769 require immediate action to address the fundamental authentication bypass issue. Organizations should implement network segmentation to isolate ATA devices from critical network segments, ensuring that even if an attacker compromises one device, they cannot easily move laterally through the network. Network access control lists should be configured to restrict access to the web interface ports only to authorized administrative workstations. Cisco released patches and firmware updates that address this specific vulnerability, and organizations must ensure they apply these updates immediately to prevent exploitation. Additionally, implementing network monitoring to detect unusual HTTP POST requests and parameter modifications can help identify potential exploitation attempts. The vulnerability serves as a critical reminder of the importance of input validation and proper authentication mechanisms in network devices, particularly those with web-based interfaces. Security teams should conduct regular vulnerability assessments of telephony infrastructure and implement security controls that align with NIST cybersecurity frameworks and ISO 27001 standards to prevent similar issues in modern deployments.