CVE-2019-10171 in 389-ds-base
Summary
by MITRE
It was found that the fix for CVE-2018-14648 in 389-ds-base, versions 1.4.0.x before 1.4.0.17, was incorrectly applied in RHEL 7.5. An attacker would still be able to provoke excessive CPU consumption leading to a denial of service.
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Analysis
by VulDB Data Team • 11/20/2023
The vulnerability identified as CVE-2019-10171 represents a critical flaw in the 389 Directory Server implementation that demonstrates the complexities and risks associated with security patch management in enterprise directory services. This issue specifically affects the 389-ds-base package version 1.4.0.x prior to 1.4.0.17, where the remediation for a previously identified vulnerability CVE-2018-14648 was improperly implemented in Red Hat Enterprise Linux 7.5. The flaw exists within the directory server's handling of certain LDAP operations that trigger excessive CPU consumption, creating a potential denial of service condition that can severely impact directory service availability.
The technical root cause of this vulnerability stems from an incorrect application of the security fix for CVE-2018-14648, which was designed to prevent resource exhaustion attacks targeting the directory server's processing capabilities. When the flawed patch was implemented, it failed to properly address the underlying mechanism that allows malicious actors to craft specific LDAP requests that consume disproportionate CPU cycles. The vulnerability manifests when an attacker submits carefully constructed LDAP operations that cause the server to enter an infinite loop or perform excessive computations, leading to sustained high CPU utilization that can render the directory service non-responsive to legitimate requests. This behavior aligns with CWE-400 vulnerability classification, which encompasses issues related to resource exhaustion and denial of service conditions.
From an operational perspective, this vulnerability presents a significant risk to organizations relying on 389 Directory Server for critical authentication and authorization services. The excessive CPU consumption can lead to complete service disruption, affecting thousands of users who depend on directory services for authentication to enterprise applications, email systems, and network resources. Attackers can exploit this vulnerability with relatively simple LDAP requests, making it particularly dangerous as it requires minimal technical expertise to execute. The impact extends beyond immediate service disruption to include potential cascading effects throughout the enterprise infrastructure, as directory services often serve as foundational components for numerous other systems and applications. This vulnerability directly maps to ATT&CK technique T1499.004, which involves network denial of service attacks targeting directory services.
The remediation for this vulnerability requires organizations to upgrade their 389-ds-base packages to version 1.4.0.17 or later, ensuring that the proper fix for CVE-2018-14648 is correctly implemented. System administrators should conduct thorough testing of the updated packages in non-production environments before deployment to verify that the fix resolves the excessive CPU consumption issue without introducing regressions in functionality. Additionally, implementing monitoring solutions that can detect unusual CPU utilization patterns and automated alerting mechanisms can help identify exploitation attempts. Organizations should also consider implementing network segmentation and access controls to limit exposure of directory services to untrusted networks, while maintaining regular vulnerability scanning to identify similar issues in other enterprise systems. The proper implementation of this security update is critical for maintaining the integrity and availability of directory services within enterprise environments.