CVE-2002-1416 in WebEasyMail
Summary
by MITRE
The POP3 service for WebEasyMail 3.4.2.2 and earlier generates diffferent error messages for valid and invalid usernames during authentication, which makes it easier for remote attackers to conduct brute force attacks.
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Analysis
by VulDB Data Team • 09/06/2025
The vulnerability identified as CVE-2002-1416 resides within the POP3 service implementation of WebEasyMail version 3.4.2.2 and earlier systems. This flaw represents a classic authentication weakness that fundamentally undermines the security posture of email services by providing distinguishable feedback to authentication attempts. The vulnerability operates at the application layer and specifically targets the authentication mechanism of the POP3 protocol implementation within this particular email server software.
The technical root cause of this vulnerability stems from the inconsistent error messaging behavior during the authentication process. When valid usernames are submitted to the POP3 service, the system generates error messages that differ significantly from those produced when invalid usernames are attempted. This differential response creates a clear signal that allows attackers to distinguish between legitimate and non-existent user accounts through automated means. The vulnerability manifests as a timing attack vector where the system's response characteristics reveal information about the validity of the attempted username, effectively creating a side-channel information leak.
From an operational impact perspective, this vulnerability enables remote attackers to conduct systematic brute force attacks against the POP3 service with significantly reduced effort and time compared to traditional approaches. Attackers can leverage the distinguishable error messages to build user account enumeration lists, which then serve as targets for password guessing or credential stuffing attacks. The vulnerability directly enables account enumeration techniques that are categorized under attack tactics such as credential access and reconnaissance within the MITRE ATT&CK framework. The security implications extend beyond simple password cracking as successful enumeration can lead to further privilege escalation and access to sensitive email communications.
This vulnerability aligns with CWE-200, which describes improper error handling that can lead to information disclosure, and represents a specific instance of information leakage through error message differentiation. The flaw also connects to CWE-305, which addresses authentication mechanisms that are vulnerable to attack through the use of predictable or distinguishable responses. The impact of this vulnerability is amplified by the fact that it affects the core authentication service of an email system, potentially allowing attackers to compromise multiple user accounts and access confidential communications. Organizations using affected versions of WebEasyMail should immediately implement mitigations including disabling unnecessary authentication methods, implementing account lockout mechanisms, and deploying intrusion detection systems to monitor for suspicious authentication patterns.
The recommended mitigation strategies include updating to patched versions of WebEasyMail, implementing rate limiting and account lockout policies, and configuring the service to provide consistent error messages regardless of username validity. Network-level protections such as firewall rules and access control lists can also help reduce the attack surface by limiting access to the POP3 service to trusted networks only. Additionally, organizations should consider implementing multi-factor authentication mechanisms to provide additional security layers beyond simple username/password combinations. The vulnerability demonstrates the critical importance of consistent error handling in security-sensitive applications and serves as a reminder that seemingly minor implementation details can have significant security implications.