CVE-2025-36631 in Tenable
Summary
by MITRE • 06/13/2025
In Tenable Agent versions prior to 10.8.5 on a Windows host, it was found that a non-administrative user could overwrite arbitrary local system files with log content at SYSTEM privilege.
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Analysis
by VulDB Data Team • 10/23/2025
This vulnerability exists within Tenable Agent software version 10.8.4 and earlier on Windows operating systems where a privilege escalation flaw allows non-administrative users to overwrite arbitrary system files with log content while operating at SYSTEM privilege level. The issue stems from improper privilege handling during log file creation and management processes, where the agent fails to properly validate file access permissions or implement adequate security controls when processing log data. This vulnerability represents a critical privilege escalation vector that directly violates the principle of least privilege and demonstrates a fundamental flaw in the agent's security architecture. The flaw enables an attacker with minimal user privileges to gain elevated system access through manipulation of log file content, effectively bypassing standard Windows security controls and user access restrictions. The vulnerability is particularly concerning because it operates at the SYSTEM privilege level, which provides complete control over the target system including the ability to modify critical system files, registry entries, and execute arbitrary code with full administrative privileges.
The technical implementation of this vulnerability involves the Tenable Agent's logging mechanism failing to properly secure file operations when processing log content. When non-administrative users can influence log file creation or modification processes, and the agent subsequently processes this content with elevated privileges, a dangerous privilege escalation path is created. The flaw likely manifests through insecure file handling routines where log data is written to system locations without proper access control validation or privilege separation. This issue aligns with CWE-276, which addresses improper file permissions, and CWE-732, which covers inadequate protection of critical resources. The vulnerability may also be categorized under ATT&CK technique T1068, privilege escalation through local exploitation, and T1548.002, abuse of group policy to gain privileges. The agent's logging subsystem appears to lack proper input validation and privilege separation mechanisms that would normally prevent non-privileged users from influencing system-level file operations.
The operational impact of this vulnerability is severe and potentially catastrophic for organizations relying on Tenable Agent for security monitoring. An attacker could leverage this vulnerability to overwrite critical system files such as executables, configuration files, or security binaries, potentially leading to system compromise, persistent backdoor installation, or complete system takeover. The vulnerability could be exploited to disable security software, modify system configurations, or install malicious payloads that persist across reboots. Organizations with multiple endpoints running affected Tenable Agent versions face significant risk of lateral movement and persistent threats, as the vulnerability allows for stealthy privilege escalation that bypasses standard endpoint detection mechanisms. The impact extends beyond individual systems to potentially compromise entire network infrastructures, especially in environments where Tenable Agent is deployed across critical infrastructure components. This vulnerability effectively undermines the security posture of organizations by providing an unauthorized path to SYSTEM-level access that could be used to establish persistent access, exfiltrate sensitive data, or disrupt critical services.
Organizations should immediately update all Tenable Agent installations to version 10.8.5 or later to remediate this vulnerability. The update addresses the privilege escalation flaw by implementing proper file access controls and privilege separation during log processing operations. System administrators should also conduct immediate vulnerability assessments to identify any potential exploitation attempts and monitor for unusual log file modifications or system behavior. Additional mitigations include implementing strict file permission controls on system directories, monitoring for unauthorized file modifications, and deploying endpoint detection and response solutions to identify potential exploitation attempts. Organizations should also review their access control policies and ensure that non-administrative users have minimal access to systems where Tenable Agent is deployed. The vulnerability highlights the importance of proper privilege management and secure coding practices, particularly in security tools that operate with elevated privileges. Regular security assessments and penetration testing should be conducted to identify similar privilege escalation vulnerabilities in other security tools and system components. Network segmentation and privilege separation should be enforced to limit the potential impact of such vulnerabilities in the event of exploitation.