Hey Dan!

Thanks. I had posted the following link before:

http://ossec-docs.readthedocs.org/en/latest/syntax/head_rules.html#element-hostname

Here is the info I see:

hostname 
<http://ossec-docs.readthedocs.org/en/latest/syntax/head_rules.html#element-hostname>
   
   - Any hostname (decoded as the syslog hostname) or log file.
   - *Allowed:* any OS_Match/sregex Syntax 
   <http://ossec-docs.readthedocs.org/en/latest/syntax/regex.html#os-match>


Would love to know if this is incorrect.

I've been able to use the "|" separator before though.

- Fran

On Monday, December 28, 2015 at 3:00:35 PM UTC-7, dan (ddpbsd) wrote:
>
>
> On Dec 28, 2015 3:17 PM, "Francisco" <[email protected] <javascript:>> 
> wrote:
> >
> > Hello,
> >
> > I'm having trouble getting Regex to work in the <hostname> field in my 
> custom OSSEC rule. According to the OSSEC documentation here I should be 
> able to use a regex in the hostname qualifier. 
> >
>
> Despite qhat the documentation might say, I don't think regex works in the 
> hostname field. Can you give me a link tonwhere it says it works so I can 
> test/and correct the documentation if necessary?
>
> > When I add any regex value to the hostname attribute it seems to be 
> ignored and never match my rule. I've tried this on 2.8.1 and 2.8.3.
> >
> > Here is the rule I'm trying to write:
> >>
> >>
> >>   <rule id="100050" level="0">
> >>     <if_sid>1002</if_sid>
> >>     <program_name>sudo</program_name>
> >>     <hostname>db\w+.blah.net</hostname>
> >>     <match>pam_unix(sudo:auth): conversation failed</match>
> >>     <description>Ignore DB sudo issues for now</description>
> >>   </rule>
> >
> >
> > I've verified that the regex works as expected using ossec-regex:
> >
> >> [root@blah ~]# /var/ossec/bin/ossec-regex 'db\w+.blah.net'
> >> dbstuff0010.blah.net
> >> +OSRegex_Execute: dbstuff0010.blah.net
> >> +OS_Regex       : dbstuff0010.blah.net
> >
> >
> >  However, when I run OSSEC-logtest the rule isn't applied:
> >
> >> [root@blah ~]# /var/ossec/bin/ossec-logtest
> >> 2015/12/28 19:50:56 ossec-testrule: INFO: Reading local decoder file.
> >> 2015/12/28 19:50:56 ossec-testrule: INFO: Started (pid: 114042).
> >> ossec-testrule: Type one log per line.
> >>
> >> 2015-12-25T06:04:13+00:00 dbstuff0010.blah.net sudo: 
> pam_unix(sudo:auth): conversation failed
> >>
> >>
> >> **Phase 1: Completed pre-decoding.
> >>        full event: '2015-12-25T06:04:13+00:00 dbstuff0010.blah.net 
> sudo: pam_unix(sudo:auth): conversation failed '
> >>        hostname: 'dbstuff0010.blah.net'
> >>        program_name: 'sudo'
> >>        log: 'pam_unix(sudo:auth): conversation failed '
> >>
> >> **Phase 2: Completed decoding.
> >>        decoder: 'pam'
> >>
> >> **Phase 3: Completed filtering (rules).
> >>        Rule id: '1002'
> >>        Level: '2'
> >>        Description: 'Unknown problem somewhere in the system.'
> >> **Alert to be generated.
> >
> >
> > Removing the <hostname> qualifier from the rule allows the rule to match:
> >
> >> [root@blah ~]# /var/ossec/bin/ossec-logtest
> >> 2015/12/28 19:53:09 ossec-testrule: INFO: Reading local decoder file.
> >> 2015/12/28 19:53:09 ossec-testrule: INFO: Started (pid: 115629).
> >> ossec-testrule: Type one log per line.
> >>
> >> 2015-12-25T06:04:13+00:00 dbstuff0010.blah.net sudo: 
> pam_unix(sudo:auth): conversation failed
> >>
> >>
> >> **Phase 1: Completed pre-decoding.
> >>        full event: '2015-12-25T06:04:13+00:00 dbstuff0010.blah.net 
> sudo: pam_unix(sudo:auth): conversation failed '
> >>        hostname: 'dbstuff0010.blah.net'
> >>        program_name: 'sudo'
> >>        log: 'pam_unix(sudo:auth): conversation failed '
> >>
> >> **Phase 2: Completed decoding.
> >>        decoder: 'pam'
> >>
> >> **Phase 3: Completed filtering (rules).
> >>        Rule id: '100050'
> >>        Level: '0'
> >>        Description: 'Ignore DB sudo issues for now'
> >
> >
> > I've tried the following regexes for the <hostname> qualifier and 
> nothing worked in the rule:
> >
> > db\w+.blah.net
> > db(\w+).blah.net
> > db(\S+).blah.net
> > db(\.*).blah.net
> > db\S+.blah.net
> > db\.+
> > dbstuff0010.blah.ne\w (for testing..)
> > \.* (as a test to attempt to match anything)
> >
> > Any ideas around here? Has anyone had luck getting regex to work in the 
> hostname qualifier?
> >
> > Would appreciate any ideas or help people can offer!
> >
> > - Francisco
> >
> > -- 
> >
> > --- 
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>

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