On Wed, May 7, 2014 at 12:02 PM, funwithossec <[email protected]> wrote:
> I appreciate the answer though it shows me how much I suck at asking
> questions :-)
>
> What I really want to ask is this, based on the excellent documentation I
> could find we *think* rootcheck is doing this:
>
> for (pid in every possible value) {
>     if (kill(pid, 0)) {
>       /* process with this pid exists */
>       char dirname[20];
>       snprintf(dirname, sizeof(dirname), "/proc/%d", (int)pid);
>       DIR *d = opendir(dirname);
>       if (d)
>         closedir(d);
>       else {
>         OMG, rootkit!
>       }
>     }
>   }
>
> But I don't know where to look in the code for the actual instruction set,
> perhaps you could point me in the right direction?
>

Rootcheck maybe?

> Also, I *think* that turning off the netstat checking features in rootcheck
> I have inadvertently caused it to loose some accuracy/efficacy and thus my
> deploy may be more prone to false positives than if I was using as intended,
> would you agree or am I way off?
>

No idea, I don't pay much attention to rootcheck.

> Lastly, if you don't hear it enough, thanks for making such an awesome tool
> for us to use.
>
> -Thanks
>
>
>
> On Tuesday, April 15, 2014 4:34:05 PM UTC-7, funwithossec wrote:
>>
>> Friends,
>>      I am running ossec server version 2.7.1 on CentOS 6.5 and my agents
>> are all running version 2.7.1 in a mix of CentOS 4-6  and Debian 4-6 hosts.
>> On all the agents and server I have rootkit detection configured as such:
>>
>> <rootcheck>
>>     <rootkit_files>/var/ossec/etc/shared/rootkit_files.txt</rootkit_files>
>>
>> <rootkit_trojans>/var/ossec/etc/shared/rootkit_trojans.txt</rootkit_trojans>
>>  </rootcheck>
>>
>> with these options removed:
>>
>> <localfile>
>>     <log_format>command</log_format>
>>     <command>df -h</command>
>>   </localfile>
>>
>>   <localfile>
>>     <log_format>full_command</log_format>
>>     <command>netstat -tan |grep LISTEN |grep -v 127.0.0.1 | sort</command>
>>   </localfile>
>>
>>   <localfile>
>>     <log_format>full_command</log_format>
>>     <command>last -n 5</command>
>>   </localfile>
>>
>> I received the following alerts from two of my agents:
>>
>> 2014 Apr 14 17:09:44 (host001) a.b.c.d->rootcheck
>> Rule: 510 (level 7) -> 'Host-based anomaly detection event (rootcheck).'
>> Process '29594' hidden from /proc. Possible kernel level rootkit.
>>
>>
>> 2014 Apr 14 18:51:49 (host002) e.f.g.h->rootcheck
>> Rule: 510 (level 7) -> 'Host-based anomaly detection event (rootcheck).'
>> Process '23067' hidden from /proc. Possible kernel level rootkit.
>>
>> I am scratching my head as to exactly what ossec did to generate these
>> alerts...can anyone help explain how this works to me pls?
>>
>>
>>
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