CVE-2020-15931 in Account Lockout Examiner
Summary
by MITRE • 10/21/2020
Netwrix Account Lockout Examiner before 5.1 allows remote attackers to capture the Net-NTLMv1/v2 authentication challenge hash of the Domain Administrator (that is configured within the product in its installation state) by generating a single Kerberos Pre-Authentication Failed (ID 4771) event on a Domain Controller.
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Analysis
by VulDB Data Team • 11/22/2020
This vulnerability exists in Netwrix Account Lockout Examiner versions prior to 5.1 and represents a significant authentication security flaw that can be exploited by remote attackers to obtain critical domain credentials. The vulnerability specifically targets the authentication mechanism used by Windows domain controllers and leverages a well-known event generation pattern to capture authentication hashes. The flaw occurs because the product's installation configuration leaves the Domain Administrator account credentials exposed in a manner that can be exploited through legitimate authentication event generation.
The technical implementation of this vulnerability exploits the Windows Kerberos authentication protocol by triggering a specific event type that generates authentication challenge hashes. When a Kerberos Pre-Authentication Failed event ID 4771 is generated on a domain controller, the system responds with an authentication challenge that includes the Net-NTLMv1/v2 hash of the configured Domain Administrator account. This occurs because the product's default installation configuration does not properly isolate or secure the authentication context, allowing attackers to capture these hashes through legitimate event generation processes.
The operational impact of this vulnerability is severe as it provides attackers with direct access to domain administrator credentials that can be used for privilege escalation and persistent access to entire domain environments. The captured hashes can be used to authenticate as the Domain Administrator account without requiring knowledge of the actual password, effectively granting attackers complete administrative control over the domain. This vulnerability can be exploited from any location with network access to the domain controller, making it particularly dangerous for organizations with remote access capabilities.
The vulnerability aligns with CWE-287 which addresses improper authentication issues, and represents a specific implementation of weak credential handling within network security tools. From an attack perspective, this flaw maps to several ATT&CK techniques including credential access through Kerberos authentication, privilege escalation through administrative access, and lateral movement using stolen credentials. The vulnerability demonstrates a critical failure in secure configuration management and proper credential isolation practices within security monitoring tools.
Organizations should immediately upgrade to Netwrix Account Lockout Examiner version 5.1 or later to remediate this vulnerability. Additionally, administrators should review and harden the default installation configurations to ensure that privileged accounts are not exposed through authentication event generation. Network segmentation and monitoring of Kerberos event generation should be implemented to detect potential exploitation attempts. Security teams should also conduct comprehensive credential audits and implement additional authentication controls including multi-factor authentication for privileged accounts. The vulnerability highlights the importance of secure configuration management and proper credential handling in security tools that interact with domain authentication systems.