CVE-2015-7966 in Authentication Service Windows Logon Agent
Summary
by MITRE
SafeNet Authentication Service Windows Logon Agent uses a weak ACL for unspecified installation directories and executable modules, which allows local users to gain privileges by modifying an executable module, a different vulnerability than CVE-2015-7965.
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Analysis
by VulDB Data Team • 01/10/2020
The SafeNet Authentication Service Windows Logon Agent vulnerability represents a critical access control flaw that undermines the security posture of enterprise authentication systems. This weakness stems from the improper implementation of access control lists within unspecified installation directories and executable modules, creating a pathway for local attackers to escalate their privileges. The vulnerability specifically affects the Windows Logon Agent component of the SafeNet Authentication Service, which serves as a critical bridge between user authentication and system access controls. Unlike other related vulnerabilities such as CVE-2015-7965, this issue focuses explicitly on the weak permissions assigned to installation directories, making it a distinct yet equally dangerous threat vector. The flaw operates at the file system level where standard security controls fail to properly restrict write access to critical executable components, allowing unauthorized modifications that can fundamentally alter the agent's behavior.
The technical implementation of this vulnerability exploits fundamental Windows security mechanisms by leveraging weak discretionary access control lists that do not adequately restrict user permissions to sensitive system components. When the SafeNet Authentication Service installs its Windows Logon Agent, it fails to properly configure access control permissions for the installation directories, leaving executable modules vulnerable to modification by local users. This weakness enables attackers to replace legitimate executable files with malicious counterparts that maintain the same name and path structure, effectively creating a backdoor within the authentication process. The vulnerability's classification aligns with CWE-276, which addresses improper permissions for security-critical resources, and represents a direct violation of the principle of least privilege. Attackers can leverage this flaw to execute arbitrary code with elevated privileges, potentially gaining full system access or compromising the entire authentication infrastructure.
The operational impact of CVE-2015-7966 extends far beyond simple privilege escalation, as it fundamentally compromises the integrity of the authentication system. Local users who can modify executable modules gain the ability to manipulate the authentication process itself, potentially allowing them to bypass authentication requirements or create persistent access mechanisms. This vulnerability creates a persistent threat vector that can be exploited repeatedly, as the weak ACLs remain in place until manually corrected. The attack surface is particularly concerning in enterprise environments where multiple users may have local access to systems running the SafeNet Authentication Service, potentially enabling insider threats or compromised accounts to escalate privileges. The vulnerability also creates opportunities for attackers to establish persistence within the system, as they can modify legitimate executables to include malicious code that executes during normal authentication operations.
Organizations affected by this vulnerability should implement immediate mitigations focused on correcting the access control configurations for the SafeNet Authentication Service installation directories. The recommended approach involves manually reviewing and updating the discretionary access control lists for all installation paths to ensure that only authorized system accounts and administrators possess write permissions. Security administrators should also consider implementing automated monitoring solutions that can detect unauthorized modifications to critical executable files and alert on potential privilege escalation attempts. The mitigation strategy should align with defensive techniques outlined in the MITRE ATT&CK framework under the privilege escalation category, specifically targeting the modification of files and execution of malicious code through weakened access controls. Additionally, organizations should conduct comprehensive vulnerability assessments to identify other systems running vulnerable versions of the SafeNet Authentication Service and ensure proper patch management procedures are in place to prevent similar access control weaknesses from occurring in other software components.