CVE-2006-0599 in Elog Web Logbook
Summary
by MITRE
The (1) elog.c and (2) elogd.c components in elog before 2.5.7 r1558-4 generate different responses depending on whether or not a username is valid, which allows remote attackers to determine valid usernames.
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Analysis
by VulDB Data Team • 07/22/2019
The vulnerability identified as CVE-2006-0599 affects the elog logging system prior to version 2.5.7 release 1558-4, specifically targeting the elog.c and elogd.c components. This security flaw represents a classic information disclosure vulnerability that stems from inconsistent response handling between valid and invalid user authentication attempts. The core issue manifests when the system generates different responses based on username validation status, creating a side-channel attack vector that adversaries can exploit to enumerate valid usernames within the system. This type of vulnerability falls under the CWE-200 category for Information Exposure and aligns with ATT&CK technique T1087.001 for Account Discovery through the exposure of authentication mechanisms.
The technical implementation of this vulnerability occurs at the authentication response level where the elog system fails to provide consistent error messages regardless of whether a username exists in the system. When an attacker submits a username for authentication, the system's response varies depending on whether that username is valid, allowing for username enumeration through response analysis. This behavior creates a predictable pattern that malicious actors can exploit to systematically determine which usernames are legitimate within the target system. The flaw essentially provides a backdoor mechanism for user account reconnaissance that bypasses normal authentication controls and directly exposes system user information.
The operational impact of this vulnerability extends beyond simple username enumeration, as it significantly weakens the overall security posture of systems utilizing affected elog versions. Attackers can leverage this information to conduct targeted brute force attacks, credential stuffing operations, or social engineering campaigns with higher success rates. The vulnerability particularly affects systems where user accounts are not protected by additional authentication layers or where username validation is not properly obfuscated. This issue can be particularly dangerous in environments where user enumeration could lead to privilege escalation or further attacks on system components that rely on the exposed user information.
Mitigation strategies for CVE-2006-0599 should focus on implementing consistent response handling throughout the authentication process to prevent information leakage. Systems administrators should immediately upgrade to elog version 2.5.7 or later where this vulnerability has been addressed through proper response normalization. Additional protective measures include implementing account lockout mechanisms, rate limiting for authentication attempts, and employing multi-factor authentication to reduce the effectiveness of username enumeration attacks. Organizations should also consider implementing intrusion detection systems that monitor for patterns consistent with username enumeration attempts and establish proper logging mechanisms to track authentication-related activities for security analysis. The vulnerability demonstrates the critical importance of consistent error handling in security-sensitive applications and aligns with security best practices outlined in NIST SP 800-53 and ISO 27001 frameworks for authentication and access control.