Claroty Discloses 11 Vulnerabilities in Nagios, Highlighting the Vulnerability of Network Management Systems


The SolarWinds and Kaseya attacks were well-documented and devastating intrusions at the heart of IT and network management supply chains. In each case, alleged state actors were able to infiltrate the mechanisms used by the vendors to ship software updates to customers, and infect those updates with malware, including ransomware. In both cases, tens of thousands of customers installed compromised updates, and the trust both vendors built with customers was damaged.

SolarWinds and Kaseya were likely targeted not only because of their large and influential customer bases, but also because of their respective technologies’ access to enterprise networks, whether it was managing IT, operational technology (OT), or internet of things (IoT) devices. Network management systems have oversight of core servers, devices, and other critical components in the enterprise network. Moreover, given that these systems are used to monitor servers, they often contain many network secrets such as credentials or API tokens that would be attractive to attackers.

Claroty’s Team82 researchers began their work by mapping popular monitoring software in various IT, IoT, and OT networks, including Nagios, or Nagios Core to be more specific.

Nagios Core is An open-source tool for monitoring IT infrastructure for performance issues, event scheduling and processing, alerting, and more functionality related to network health. Nagios XI is a proprietary web-based platform using Nagios Core. XI expands Core’s capabilities by adding additional features to enhance IT operations. Network operations center staff and system administrators use the platform to view the current state of managed servers and workstations. Nagios says that thousands of organisations worldwide use its software to monitor networks; Comcast, Shell, DHL, L’Oreal, Texas Instruments, Toshiba, and dozens of other companies are listed on its website as users.

Team82’s research found 11 exploitable vulnerabilities in Nagios XI that can lead to remote code execution with the same privileges as an Apache user (Nagios XI commonly runs on an Apache web server), credential theft, phishing attacks, local privilege escalation to user permissions, and local privilege escalation to root. By chaining some of these vulnerabilities, an attacker can achieve post-authentication remote code execution with high privileges (root)


  1. CVE-2021-37353: Nagios XI Docker Wizard before version 1.1.3 is vulnerable to server-side request forgery (SSRF) due to improper sanitization in table population.php
  2. CVE-2021-37352: An open redirect vulnerability exists in Nagios XI before version 5.8.5 that could lead to spoofing. To exploit the vulnerability, an attacker could send a link that has a specially crafted URL, and convince the user to click the link.
  3. CVE-2021-37351: Nagios XI before version 5.8.5 is vulnerable to insecure permissions and allows unauthenticated users to access guarded pages through a crafted HTTP request to the server.
  4. CVE-2021-37350: Nagios XI before version 5.8.5 is vulnerable to SQL injection vulnerability in the Bulk Modifications Tool due to improper input sanitization.
  5.  CVE-2021-37349: Nagios XI before version 5.8.5 is vulnerable to local privilege escalation because cleaner.php does not sanitize input read from the database.
  6.  CVE-2021-37348: Nagios XI before version 5.8.5 is vulnerable to local file inclusion through improper limitation of a pathname in index.php.
  7. CVE-2021-37347: Nagios XI before version 5.8.5 is vulnerable to local privilege escalation because does not validate the directory name it receives as an argument.
  8. CVE-2021-37346: Nagios XI WatchGuard Wizard before version 1.4.8 is vulnerable to remote code execution through Improper neutralization of special elements used in an OS command (OS Command injection).
  9. CVE-2021-37345: Nagios XI before version 5.8.5 is vulnerable to local privilege escalation because xi-sys.cfg is being imported from the /var directory for some scripts with elevated permissions.
  10.  CVE-2021-37344: Nagios XI Switch Wizard before version 2.5.7 is vulnerable to remote code execution through improper neutralization of special elements used in an OS command (OS Command injection).
  11.  CVE-2021-37343: A path traversal vulnerability exists in Nagios XI below version 5.8.5 AutoDiscovery component and could lead to post-authenticated RCE under the security context of the user running Nagios.


In August, Nagios addressed the vulnerabilities privately disclosed by Team82 through updates to Nagios XI, Nagios XI Docker Wizard, Nagios XI WatchGuard Wizard, and Nagios XI Switch Wizard. Users are urged to immediately update all affected systems, and follow some basic rules about keeping network management systems secure.

TRUST: These systems require extensive trust and access to network components in order to properly monitor network behaviors and performance for failures and poor efficiency. They may also extend outside your network through the firewall to attend to remote servers and connections. Therefore, these centralized systems can be a tasty target for attackers who can leverage this type of network hub, and attempt to compromise it in order to access, manipulate, and disrupt other systems.

MONITOR: Access to the network management system should be closely monitored and limited to privileged insiders. All connections and activity should be monitored and alerted upon.