CVE-2004-2150 in Intellipeer Email Server
Summary
by MITRE
Nettica Corporation INTELLIPEER Email Server 1.01 displays different error messages for valid and invalid account names, which allows remote attackers to determine valid account names.
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Analysis
by VulDB Data Team • 06/05/2019
The vulnerability identified as CVE-2004-2150 affects the Nettica Corporation INTELLIPEER Email Server version 1.01, presenting a significant information disclosure weakness that directly impacts the security posture of email infrastructure. This flaw operates at the application layer and specifically targets the authentication mechanism of the email server, creating a scenario where attackers can exploit differences in error messaging to enumerate valid user accounts. The vulnerability stems from the server's inconsistent response behavior when processing authentication requests, providing distinct error messages for legitimate versus non-existent accounts, which violates fundamental security principles of least privilege and secure error handling.
This vulnerability represents a classic example of insecure error handling and information leakage, categorized under CWE-209 in the Common Weakness Enumeration system, which specifically addresses "Information Exposure Through an Error Message." The flaw enables what security professionals refer to as account enumeration attacks, where malicious actors systematically test account names to identify valid users within the system. The operational impact extends beyond simple reconnaissance as it provides attackers with a foundational element for subsequent attacks, including brute force attempts, credential stuffing, and social engineering campaigns that rely on accurate user information. The vulnerability directly maps to techniques described in the MITRE ATT&CK framework under T1078 - Valid Accounts, where adversaries leverage valid credentials to maintain access and move laterally within networks.
The technical implementation of this vulnerability demonstrates poor security design principles in the authentication subsystem where the server fails to implement consistent error responses regardless of account validity. When a user attempts to authenticate with a valid account, the server returns one type of error message, while invalid account attempts generate different responses, creating a clear pattern that attackers can exploit. This behavior violates the principle of security through obscurity and more fundamentally undermines the security model of the email server by providing attackers with actionable intelligence about the system's user base. The flaw essentially transforms a security mechanism designed to protect the system into a tool that reveals system information to unauthorized parties, making the server more susceptible to various attack vectors that depend on knowledge of valid user accounts.
Organizations utilizing this email server version should implement immediate mitigations including configuration changes that ensure all authentication attempts return identical error messages, regardless of account validity. The recommended approach involves modifying the server's authentication response logic to normalize error handling and eliminate the information disclosure. Additionally, implementing account lockout mechanisms and rate limiting can prevent automated enumeration attempts, while network-level controls such as firewalls and intrusion detection systems can monitor for suspicious authentication patterns. The vulnerability highlights the critical importance of proper error handling in security-sensitive applications and underscores the need for comprehensive security testing that includes validation of error message consistency. Security teams should also consider implementing additional layers of authentication such as multi-factor authentication to reduce the impact of credential compromise and establish monitoring procedures to detect account enumeration attempts. Regular security audits and penetration testing should be conducted to identify similar vulnerabilities in other components of the email infrastructure and ensure that all security controls are functioning as intended.