CVE-2017-15135 in 389-ds-base
Summary
by MITRE
It was found that 389-ds-base since 1.3.6.1 up to and including 1.4.0.3 did not always handle internal hash comparison operations correctly during the authentication process. A remote, unauthenticated attacker could potentially use this flaw to bypass the authentication process under very rare and specific circumstances.
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Analysis
by VulDB Data Team • 12/27/2019
The vulnerability identified as CVE-2017-15135 affects the 389 Directory Server base component, specifically versions ranging from 1.3.6.1 through 1.4.0.3. This issue resides within the authentication mechanism of the directory service, which serves as a critical infrastructure component for identity management and access control in enterprise environments. The 389 Directory Server implements the Lightweight Directory Access Protocol and is widely deployed in organizations requiring centralized user and resource management. The flaw manifests during internal hash comparison operations that occur when processing authentication requests, representing a fundamental weakness in how the system validates credentials.
The technical nature of this vulnerability stems from incorrect handling of hash comparison operations during authentication workflows. When users attempt to authenticate against the directory server, the system performs internal cryptographic operations to verify the submitted credentials against stored hash values. The flaw occurs in the comparison logic that evaluates these hash values, potentially allowing an attacker to craft authentication requests that bypass the normal validation process. This represents a classic weakness in cryptographic implementation where the comparison algorithm fails to properly validate hash values, creating a potential authentication bypass scenario. The vulnerability is classified under CWE-284 Access Control Bypass, as it allows unauthorized access to systems protected by authentication mechanisms. The specific conditions required for exploitation are described as "very rare and specific," indicating that while the vulnerability exists, successful exploitation requires precise circumstances that may not occur frequently in typical deployment environments.
The operational impact of this vulnerability extends beyond simple authentication bypass, as it represents a potential pathway for unauthorized access to sensitive directory services and the resources they protect. Organizations relying on 389-ds-base for user authentication and access control could face security breaches where attackers gain unauthorized access to systems, applications, and data that should be protected by proper authentication mechanisms. The remote and unauthenticated nature of the attack vector means that adversaries do not need valid credentials or network access privileges to attempt exploitation, making the vulnerability particularly concerning for systems exposed to untrusted networks. This weakness could enable attackers to escalate privileges, access sensitive information, or potentially move laterally within networks where directory services are used for authentication and authorization. The vulnerability's impact is further amplified by the widespread deployment of 389-ds-base in enterprise environments, where directory services often serve as central points of authentication for multiple applications and systems.
Mitigation strategies for CVE-2017-15135 should prioritize immediate patching of affected systems to versions that address the hash comparison implementation flaw. Organizations should conduct comprehensive inventory assessments to identify all systems running vulnerable versions of 389-ds-base and prioritize remediation efforts accordingly. Network segmentation and access controls should be implemented to limit exposure of directory services to untrusted networks while patches are deployed. Security monitoring should be enhanced to detect unusual authentication patterns or attempts that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper cryptographic implementation and validation in authentication systems, aligning with ATT&CK technique T1078 Valid Accounts which emphasizes the use of legitimate credentials for unauthorized access. Regular security assessments and code reviews focusing on cryptographic implementations should be conducted to identify similar weaknesses in other authentication mechanisms. Additionally, organizations should maintain updated threat intelligence feeds to monitor for exploitation attempts targeting directory services and implement appropriate incident response procedures to address potential breaches. The vulnerability serves as a reminder of the critical importance of proper hash validation and comparison operations in security-sensitive systems, particularly those handling user authentication and access control functions.