Tenable Network Monitor Flaws Could Let Attackers Manipulate Alerts, Execute Code

Key Takeaways

• Three flaws affect Tenable Network Monitor: CVE-2025-4647, CVE-2025-4648, and CVE-2025-4649.
• The most serious is an RCE in the alerting mechanism, letting attackers run code remotely.
• Patches are available; administrators should upgrade and validate integrity of rule sets and permissions.

Vulnerabilities Overview

• CVE-2025-4647 (Remote Code Execution in Email Alerting)
  A specially crafted email can trigger code execution in the TNM alerting subsystem. If attackers can send emails that the system processes, they may execute commands under the context of the monitoring application.
• CVE-2025-4648 (Alert Rule Manipulation)
  This flaw permits local authenticated users to manipulate alert rules—adding, deleting, or modifying rules to hide malicious activity or suppress detection.
• CVE-2025-4649 (Data Leakage / Unauthorized Access)
  In certain scenarios, attackers may gain access to sensitive internal data due to mispermission handling across modules, causing unauthorized disclosure.

Impact

• Attack scope: The RCE via email alerts presents the most direct external risk, especially in environments where TNM is exposed to mail or untrusted sources.
• Insider threat risks: Manipulating alert rules or suppressing detection gives malicious insiders or compromised accounts an opportunity to hide malicious actions.
• Operational risk: Tampering with the monitoring system undermines trust in alerts, potentially causing teams to miss real incidents.
• Prerequisites: Some vulnerabilities require local or authenticated access; others hinge on email channels being improperly protected.

Recommended Actions

• Apply patches/updates immediately: Upgrade to the fixed versions provided by Tenable.
• Harden mail ingestion paths: Restrict which email addresses or domains TNM will process alerts from, ideally using allowlists and authentication.
• Restrict TNM config permissions: Limit which users/processes can modify alert rules and rule sets.
• Validate rule integrity: Periodically compare active alert rules against baselines or approved templates.
• Monitor for unauthorized changes: Use file integrity monitoring or change detection on config directories and rule files.
• Isolate the monitoring system: Ensure network segmentation so that TNM isn’t exposed to untrusted networks or email paths.