CVE-1999-1152 in Microcom 6000 Access Integrator
Summary
by MITRE
Compaq/Microcom 6000 Access Integrator does not disconnect a client after a certain number of failed login attempts, which allows remote attackers to guess usernames or passwords via a brute force attack.
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Analysis
by VulDB Data Team • 04/17/2026
The vulnerability identified as CVE-1999-1152 affects the Compaq/Microcom 6000 Access Integrator, a network access control device that serves as a gateway for remote users to connect to corporate networks. This device operates as a critical component in enterprise network security infrastructure, managing authentication and access control for remote connections. The flaw resides in the device's authentication mechanism which lacks proper account lockout or session termination capabilities following unsuccessful login attempts. This represents a fundamental security weakness in the device's access control implementation that directly undermines its primary function of protecting network resources.
The technical flaw stems from the absence of account lockout functionality within the authentication process of the Access Integrator. When users attempt to authenticate with incorrect credentials, the system continues to accept login attempts without implementing any mechanism to terminate sessions or temporarily disable accounts. This allows attackers to perform unlimited brute force attacks against user accounts, systematically trying different username and password combinations until successful access is achieved. The vulnerability specifically targets the authentication session management rather than the encryption or network protocols themselves, making it a classic example of weak credential handling. The device's configuration does not include any built-in protection mechanisms such as account lockout thresholds, temporary account disabling, or session timeout controls that would normally prevent automated attack vectors.
The operational impact of this vulnerability is significant for organizations relying on the Compaq/Microcom 6000 Access Integrator for remote access control. Attackers can leverage this weakness to conduct systematic brute force attacks against user accounts, potentially compromising sensitive network resources and corporate data. The vulnerability enables credential stuffing attacks where attackers can use automated tools to rapidly test multiple password combinations against a target user account. Organizations may face unauthorized access to their networks, data breaches, and potential lateral movement within their infrastructure. The attack vector is particularly dangerous because it requires minimal resources and can be automated, making it accessible to attackers with basic technical skills. This vulnerability essentially renders the device's authentication mechanism useless for protecting against automated credential attacks, undermining the entire security posture of remote access management.
The security implications of CVE-1999-1152 align with CWE-307, which addresses "Improper Restriction of Excessive Authentication Attempts." This weakness specifically relates to the lack of proper rate limiting or account lockout mechanisms that should be implemented to prevent brute force attacks. From an ATT&CK framework perspective, this vulnerability maps to technique T1110.003, which covers "Brute Force: Password Guessing," and T1078.002, which addresses "Valid Accounts: Default Accounts." The vulnerability also relates to the broader category of access control weaknesses that can be exploited to gain unauthorized system access. Organizations should consider implementing additional security controls such as network segmentation, intrusion detection systems, and monitoring for suspicious authentication patterns. The lack of built-in protection mechanisms in the device requires organizations to rely on external compensating controls, which may not be sufficient to prevent successful attacks. This vulnerability demonstrates the critical importance of proper session management and authentication controls in network security appliances, particularly those handling remote access functions.
Mitigation strategies for this vulnerability include implementing external authentication controls such as firewall rules that limit the number of connection attempts from specific IP addresses, deploying intrusion prevention systems that can detect and block brute force attack patterns, and configuring additional network security measures to monitor for unusual authentication activity. Organizations should also consider upgrading to newer access control solutions that include proper account lockout mechanisms and session management features. The device should be configured with strong password policies, and administrators should implement monitoring procedures to detect potential brute force attack attempts. Network administrators should regularly review authentication logs for suspicious patterns and implement automated alerts when unusual login activity is detected. Additionally, organizations should consider implementing multi-factor authentication as an additional layer of security to protect against credential compromise even if the primary authentication mechanism is bypassed. The vulnerability highlights the importance of comprehensive security testing and the need for regular security assessments of network infrastructure components.