Rudolph Pereira (rudolph.pereira) reports:

Summary:
---------------
CVE-ID: CVE-2013-1362
CVSS: Base Score 7.5
CVSS2 Vector: AV:N/AC:L/Au:N/C:P/I:P/A:P/E:U/RL:OF/RC:UC/CDP:N/TD:N/CR:L/IR:L/AR:L
Vendor: Nagios
Affected Products: NRPE
Affected Platforms: All
Affected versions: < 2.14
Remote Exploitable: Yes
Local Exploitable: No
Patch Status Vendor released a patch (See Solution)
URL: http://www.occamsec.com/vulnerabilities.html#nagios_metacharacter_vulnerability

Description
----------------
nrpe 2.13 has, in src/nrpc.c, line 52:

#define NASTY_METACHARS         "|`&><'\"\\[]{};"

This allows the passing of $() to plugins/scripts which, if run under
bash, will execute that shell command under a subprocess and pass the
output as a parameter to the called script. Using this, it is possible
to get called scripts, such as check_http, to execute arbitrary
commands under the uid that NRPE/nagios is running as (typically,
'nagios').

Solution
------------
Upgrade to NRPE 2.14 or later, available at
http://sourceforge.net/projects/nagios/files/nrpe-2.x/

External References:

http://seclists.org/bugtraq/2013/Feb/119
http://www.occamsec.com/vulnerabilities.html#nagios_metacharacter_vulnerability