The host names are fixed, and I cannot change them. Yes, maybe someone else will chime in with a solution...

On 3/4/2011 4:39 PM, Jeremy Lee wrote:
There might be another way... I'm sure someone will chime in if they have an idea. I just can't think of anything else off the top of my head. If anything, there would have to be a way to grab it via the decoder. Actually, you might be able to use <regex> if you type in the actual hostname <regex>785</regex> - this wouldn't be much different than <hostname> however. Unless you add a common prefix to all your servers like "POS785" etc. Then maybe you could use a regex rule to filter based on <regex>POS*</regex> or something like that. My regex is off but you get the idea.



On Fri, Mar 4, 2011 at 4:20 PM, Lars Oberg <[email protected] <mailto:[email protected]>> wrote:

    That's too bad.  Maintaining that rule with about 100 hosts names
    will be too much work to be feasible, so I don't think I have a
    choice but to ignore the rule altogether.

    At least I don't have to keep banging my head on this problem
    anymore.

    Thanks for your help.

    Lars


    On 3/4/2011 3:44 PM, Jeremy Lee wrote:
    If you need to enter multiple hostnames, the delimiter is "|"

    Let us know what you find.

    On Fri, Mar 4, 2011 at 3:39 PM, Jeremy Lee <[email protected]
    <mailto:[email protected]>> wrote:

        Not sure what you would modify in decoder.xml to get the
        5100/5113 rules to pickup source IP... Because it seems like
        the 5100 base rule is not relying on a decoder but rather
        program_name - in this case "^kernel"

        In this scenario, I *think* you may need to utilize
        <hostname> (what I had suggested in your other thread). The
        drawback is that you'll have to add a long list of
        hostnames... because I'm assuming this is for all those Linux
        boxes you're monitoring, right?

        I'm not sure if you can use regex in the <hostname> attribute
        but it's not difficult to test. Especially with ossec-logtest.



        On Fri, Mar 4, 2011 at 3:24 PM, Lars Oberg
        <[email protected] <mailto:[email protected]>> wrote:

            Hi Dan,

            Thanks for clarifying that.  If I understand you
            correctly: even though the alert log shows the IP
            address, I cannot match on it using RegEx since it is not
            part of the actual message body from syslog.

            Is there another way to suppress these e-mails, or do I
            have to mess with the decoder, so that it decodes the
            source IP?

            Lars



            On 3/4/2011 2:59 PM, dan (ddp) wrote:

                Hi Lars,

                On Fri, Mar 4, 2011 at 5:54 PM, Lars
                Oberg<[email protected]
                <mailto:[email protected]>>  wrote:

                    Actually, it does - I tested the RegEx against
                    the email alert, and it
                    matches.  But I tested with PCRE regex.  Is there
                    a different flavor regex I
                    need to use?

                The OSSEC regex.
                http://www.ossec.net/doc/syntax/regex.html

                    Also, if the regex is not correct, how come the
                    other rule (100201) fires?

                100201 Deals with the log message: "ossec: Agent
                started: '785->10.1.3.4'."
                That log message contains an IP address.

                100200 deals with the log message: "Mar  4 12:47:55
                l785 kernel:
                Kernel log daemon terminating."
                That log message does not contain an IP address.

                    On 3/4/2011 2:05 PM, dan (ddp) wrote:

                        The log message in 5113 does not appear to
                        contain an IP address:
                        "Mar  4 12:47:55 l785 kernel: Kernel log
                        daemon terminating."

                        A regex for an IP would not match that log
                        message.

                        On Fri, Mar 4, 2011 at 4:57 PM, Lars
                        Oberg<[email protected]
                        <mailto:[email protected]>>    wrote:

                            I have a rule for which I cannot seem to
                            disable the email alerts.  Since
                            SrcIp is not decoded for this rule, I am
                            using a regex.  Below is my
                            local_rules.xml file (only 2 rules).  The
                            rule that doesn't fire is
                            100200,
                            but the strange thing is that the rule
                            below it (100201) is firing just
                            fine, use the exact same regex to match
                            on the IP address of the
                            workstation
                            I'm testing on.

                            This is very confusing to me, but I am
                            new to ossec, so I am hopefully
                            just
                            overlooking something simple.

                            Below is also the e-mail notification I
                            am trying to suppress as well as
                            the
                            contents of the alert log.

                            What am I missing?


                            ----- local_rules.xml -----
                            <group name="local,syslog,">

                            <rule id="100200" level="2">
                            <if_sid>5113</if_sid>
                            <regex>(10\.\d*\.3\.\d*)|(10.1.1.152)</regex>
                            <options>no_email_alert</options>
                            <description>No e-mail alerts for work
                            stations shutting
                            down.</description>
                            </rule>

                            <rule id="100201" level="2">
                            <if_sid>503</if_sid>
                            <regex>(10\.\d*\.3\.\d*)|(10.1.1.152)</regex>
                            <options>no_email_alert</options>
                            <description>No email alerts when work
                            stations start up.</description>
                            </rule>

                            </group> <!-- SYSLOG,LOCAL -->


                            ----- Email -----
                            OSSEC HIDS Notification.
                            2011 Mar 04 12:47:56

                            Received From: (785)
                            10.1.3.4->/var/log/messages
                            Rule: 5113 fired (level 7) ->    "System
                            is shutting down."
                            Portion of the log(s):

                            Mar  4 12:47:55 l785 kernel: Kernel log
                            daemon terminating.

                             --END OF NOTIFICATION



                            ----- Alert log (notice that 5113 fires,
                            instead of 100200) -----
                            ** Alert 1299272104.152207: mail  -
                            syslog,linuxkernel,system_shutdown,
                            2011 Mar 04 12:55:04 (785)
                            10.1.3.4->/var/log/messages
                            Rule: 5113 (level 7) ->    'System is
                            shutting down.'
                            Src IP: (none)
                            User: (none)
                            Mar  4 12:55:03 l785 kernel: Kernel log
                            daemon terminating.


                            ** Alert 1299272227.153206: - local,syslog,
                            2011 Mar 04 12:57:07 (785) 10.1.3.4->ossec
                            Rule: 100201 (level 2) ->    'No email
                            alerts when POS stations start up.'
                            Src IP: (none)
                            User: (none)
                            ossec: Agent started: '785->10.1.3.4'.











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