Nagios XI Flaw Exposes User Details and Emails to Unauthenticated Attackers”

A security vulnerability in Nagios XI 2024R1.2.2, tracked as CVE-2024-54961, has been disclosed, allowing unauthenticated attackers to retrieve sensitive user information, including usernames and email addresses, from the network monitoring platform.

This high-severity flaw (CVSSv3 score: 6.5) exposes organizations to heightened risks of phishing campaigns, credential-stuffing attacks, and lateral movement within compromised networks.

Technical Breakdown of the Vulnerability

The vulnerability resides in improper access controls within Nagios XI’s web interface.

Unauthenticated attackers can directly access multiple administrative pages via crafted HTTP requests, bypassing authentication mechanisms designed to restrict sensitive data.

Exploitation does not require advanced tools or techniques—attackers need only navigate to vulnerable endpoints, such as user management or system configuration panels, to extract plaintext usernames and associated email addresses.

This information disclosure flaw (CWE-200) stems from insufficient validation of user sessions.

Nagios XI 2024R1.2.2 fails to verify permissions for specific API endpoints, enabling unauthorized enumeration of user accounts.

Security researchers note that exposed email addresses could facilitate targeted social engineering attacks, while usernames provide adversaries with a starting point for brute-force password-guessing attempts.

Implications for Enterprise Security

The exposure of user credentials poses immediate risks:

1. Phishing Acceleration: Attackers can craft hyper-personalized phishing emails using legitimate email addresses, increasing the likelihood of successful credential harvesting.
2. Password Attacks: With valid usernames, adversaries can automate login attempts against Nagios XI’s web interface or reused credentials across corporate systems.
3. Supply Chain Compromise: Nagios XI often integrates with privileged systems like Active Directory; compromised credentials could grant access to broader infrastructure.

Notably, this vulnerability continues a pattern of access control failures in Nagios XI.

In 2023, four critical flaws (CVE-2023-40931 to CVE-2023-40934) allowed similar data extraction via SQL injection and cross-site scripting (XSS), highlighting systemic issues in the platform’s security architecture.

Mitigation and Response

Nagios Enterprises has released patches in subsequent versions, urging all users to immediately upgrade to Nagios XI 2024R1.2.3 or later.

Organizations unable to patch should:

• Restrict network access to Nagios XI interfaces using firewall rules.
• Implement Web Application Firewalls (WAFs) to block unauthorized access to /nagiosxi/admin/ paths.
• Monitor logs for unusual access patterns to user management endpoints.

Historical Context and Persistent Risks

This disclosure follows a 2021 audit revealing 24 vulnerabilities in Nagios XI, including remote code execution flaws.

The recurrence of authentication bypass issues underscores the challenges of securing complex monitoring platforms.

Enterprises must assume legacy Nagios deployments harbor undisclosed vulnerabilities and adopt zero-trust principles for monitoring systems.

CVE-2024-54961 serves as a critical reminder of the risks inherent in network monitoring tools.

Security teams should prioritize patching, segment monitoring infrastructure, and conduct regular access control audits.

As attackers increasingly target operational technology, securing platforms like Nagios XI becomes essential to maintaining organizational resilience against evolving cyber threats.

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