NagVis 1.9.33 Arbitrary File Read Vulnerability (CVE-2022-46945): Analysis and Mitigation

A critical vulnerability in NagVis 1.9.33, tracked as CVE-2022-46945, allows unauthenticated attackers to read arbitrary files via a path traversal flaw in the `ajax_handler.php` component. This issue, which carries a CVSS score of 7.5, exposes sensitive system files such as `/etc/passwd` through a simple HTTP request manipulation. The vulnerability has been publicly documented in ExploitDB (EDB-ID 52229) and patched in NagVis 1.9.34.

Technical Breakdown

The vulnerability stems from insufficient input validation in the `getHoverUrl` function of NagVis’ core AJAX handler. Attackers can exploit this by injecting a `file://` protocol URL into the `url[]` parameter. The following Python snippet demonstrates the exploit:

import requests
params = {"mod": "General", "act": "getHoverUrl", "url[]": "file:///etc/passwd"}
requests.get("http://target/nagvis/server/core/ajax_handler.php", params=params).text

This flaw is particularly dangerous in default NagVis installations where the web interface is exposed to untrusted networks. Successful exploitation could lead to credential harvesting, configuration file leaks, or reconnaissance for further attacks.

Impact and Relevance

NagVis is widely used in IT monitoring environments, often integrated with systems like Nagios. The arbitrary file read capability provides attackers with a foothold for lateral movement in monitored networks. This vulnerability is especially concerning for organizations using NagVis to visualize sensitive infrastructure data.

Security teams should note that the exploit requires no authentication and leaves minimal forensic traces in standard web logs. The simplicity of the attack vector makes it attractive for automated scanning tools and botnets.

Mitigation Strategies

The primary mitigation is upgrading to NagVis 1.9.34 or later. For organizations unable to immediately patch, the following temporary measures can reduce risk:

Restrict access to NagVis web interfaces using network ACLs
Implement WAF rules to block requests containing `file://` protocol handlers
Monitor for unusual file access patterns in web server logs

Organizations should also review any exposed NagVis instances for signs of compromise, particularly unexpected file access attempts or subsequent suspicious activity from the NagVis server.

Broader Security Context

This vulnerability appears alongside other high-impact issues in 2025, including critical flaws in Erlang/OTP SSH (CVE-2025-32433) and ASUS AiCloud routers (CVE-2025-2492). The NagVis case highlights persistent challenges in web application security, particularly around input validation and protocol handling.

The MITRE CVE program’s funding challenges, temporarily extended by CISA in April 2025, underscore the importance of timely vulnerability management. Organizations relying on NagVis should prioritize this update given the exploit’s simplicity and potential impact.

Conclusion

CVE-2022-46945 demonstrates how seemingly minor input validation oversights can lead to significant security breaches. The availability of public exploit code increases the urgency for patching. Security teams should treat this as a priority remediation item, particularly in environments where NagVis interfaces with critical monitoring infrastructure.

Future research may reveal additional attack vectors in network monitoring tools. Proactive security teams should consider implementing software composition analysis tools to identify vulnerable components before exploits emerge.