Nagios - CVE-2016-9565

Nagios offers monitoring and alerting services for servers, switches, applications and services. It alerts users when things go wrong and alerts them a second time when the problem has been resolved. For more details on Nagios.


Vulnerability in Nagios could enable remote attackers who can  manage to impersonate the feed server through DNS Poisoning, ARP Spoofing.. etc. to provide a malicious response that injects parameters to  curl command used by the affected RSS client class and effectivelyread/write arbitrary files on the vulnerable Nagios server.

This could lead to Remote Code Execution in the context of www-data/nagios user
on default Nagios installs that follow the official setup guidelines.This occurs because of using Vulnerable component for handling RSS new feeds.

This component was used by Nagios front-end to load news feeds from remote feed source upon log-in.The component was found vulnerable to CVE-2008-4796.

Full vulnerability report along including POC with relevant parts of code and Injection points can be found at :

Business Impact

Upon successful mitigation the attacker can extract sensitive data from the Nagios monitoring server as well as achieve arbitrary code execution as demonstrated by the exploit.

Corporate monitoring servers with a large number of connected hosts are often left unpatched due to their sensitive/central role on the network  which increase the chances of exploitation.

As explained in the description section, the vulnerability could be a threat  coming from the Internet. If a major ISP / DNS, or site itself was  compromised, this could potentially allow attackers to exploit the vulnerability on multiple Nagios installations which retrieve RSS feeds automatically and the corporate firewall does not stop the egress traffic from the monitoring server.

As a result, an attacker could potentially gain unauthorised access to  affected Nagios installations without even knowing the target IP addresses and despite a lack of direct access to the target (blocked igress traffic on the firewall).

Versions Affected

Both of the Nagios Core stable branches 3.x and 4.x are affected.This vulnerability was disclosed responsibly to the vendor and was fully fixed in Nagios Core 4.2.2. Ensure that you are using  Nagios 4.2.2.

Recommended Solution

Update to the Latest Nginx Core release. For more details in upgrading Nagios on Linux  refer 2daygeek .

  1. In the IPS tab, click Protections and find the Nagios XI Command Injection protection using the Search tool and Edit the protection’s settings.
  2. Install policy on all modules.



Video PoC:

Exploit source code:

Nagios patch history:

MagpieRSS CVE-2008-4796:

Nagios Core installation guide:


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