Check_MK Werk 2252: mk_logwatch: Fixed mostly uncritical command injection from config

Lars Michelsen lm at mathias-kettner.de
Fri May 8 10:13:00 CEST 2015


ID:          2252
Title:       mk_logwatch: Fixed mostly uncritical command injection from config
Component:   Checks & Agents
Level:       1
Class:       Security Fix
Version:     1.2.7i1

This change fixes a security related issue n the <tt>mk_logwatch</tt> linux agent
plugin. It was possible to inject commands to the agent plugin when having write access
to the logwatch.cfg configuration file. This might result in privilege
escalation issues in very rare conditions.

>From our point of view this is a low impact issue for nearly all installations
out there. Most installations run the agent as root but also have the
<tt>logwatch.cfg</tt> only being writable by root. So if a user has write
access to this file the user don't need to do privilege escalation anymore
since he is already root.

If you have the situation where the agent is executed in <i>another</i> user context
than the configuration file <tt>logwatch.cfg</tt> can be written, you should update
to the fixed <tt>mk_logwatch</tt> plugin.

Short Q/As:

<b>What does the attacker need?</b>

He needs to have write access to the <tt>/etc/check_mk/logwatch.cfg</tt>, which is
normally only writable by root.

<b>What does the attacker get?</b>

He can execute commands in context of the Check_MK-Agent (often root).

<b>Do I need to update asap?</b>

Only if non-root users can edit the <tt>logwatch.cfg</tt>.

<b>I want to update, where can I get the fixed version?</b>

If we did not release an updated version yet, you can get it from the git:

http://git.mathias-kettner.de/git/?p=check_mk.git;a=blob_plain;f=agents/plugins/mk_logwatch;hb=refs/heads/1.2.6



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