Nagios XI vulnerabilities open enterprise IT infrastructure to attack

Researchers have unearthed 11 vulnerabilities affecting Nagios XI, a widely used enterprise IT infrastructure/network monitoring solution, some of which can be chained to allow remote code execution with root privileges on the underlying system.

Attackers are likely to try to exploit vulnerabilities in network management systems like Nagios because their oversee critical network components and core servers and often contain many network secrets (e.g., credentials, API tokens) so they can do their job, Claroty researchers noted.

About Nagios Core and Nagios XI

Nagios Core is free and open-source software that monitors systems, networks and infrastructure.

Nagios XI is a proprietary user interface with Nagios Core as the back-end and the addition of other technologies and advanced features for monitoring, alerting, graphing, and reporting.

The Nagios team boasts of their solutions being used by thousands of organizations around the world, including the likes of Comcast, DHL, Shell and Toshiba.

The discovered Nagios XI vulnerabilities

Numbered sequentially from CVE-2021-37343 to CVE-2021-37353, the vulnerabilities affect:

• Nagios XI before version 5.8.5
• Nagios XI Switch Wizard before version 2.5.7
• Nagios XI Docker Wizard before version 1.13, and
• Nagios XI WatchGuard before version 1.4.8

CVE-2021-37343 allows, for example, an attacker to abuse a lack of checks to write a file inside a directory of the web server and, thus, drop a webshell or execute PHP scripts, or write PHP code inside a crontab and achieve code execution in the Apache’s user context.

CVE-2021-37347, on the other hand, involves a vulnerable sudo script that allows users to elevate their privileges from Apache user (Nagios XI commonly runs on an Apache web server) to root user.

The researchers have created a proof-of-concept exploit to demonstrate how the two can be concatenated to achieve a reverse shell with root privileges.

The remaining vulnerabilities can be used to mount server-side request forgery (SSRF) attacks, perform URL spoofing, SQL injection, and more.

Fixes are available

The good news is that the vulnerabilities have all been fixed: the Nagios team released security update for Nagios XI, Nagios XI Docker Wizard, Nagios XI WatchGuard Wizard, and Nagios XI Switch Wizard, and administrators are urged to apply them as soon as possible.

In addition to that, they urge them to limit access to the network management system only to privileged insiders and to closely monitor access to and activity on it.