Remote Yes

Type Arbitrary command execution

Description

Incomplete blacklist vulnerability in nrpc.c in Nagios Remote Plug-In Executor (NRPE) might allow remote attackers to execute arbitrary shell commands via "$()" shell metacharacters, which are processed by bash.

AVG-587 nrpe 3.2.1-2 3.2.1-3 High Fixed FS#57120

18 Jan 2018 ASA-201801-14 AVG-587 nrpe High arbitrary command execution

http://seclists.org/bugtraq/2013/Feb/119
https://github.com/NagiosEnterprises/nrpe/commit/eaaebb3c2925f9aee74319b61264ee535784b859

This issue can only occur when nrpc is compiled with --enable-command-args and the administrator enables the "dont_blame_nrpe" option in nrpe.conf despite the "HIGH security risk" warning within the comments.

Test Exploit:
# ./check_nrpe -n -H 127.0.0.1 -c check_disk -a "-c $(touch /tmp/VULNERABLE)"