This article might help too:

http://www.ossec.net/dcid/?p=87

"
If you ever had trouble with hidden ports on Linux (2.4 and 2.6), I
may have figured out one of the possible causes today (and no, it is
not a rootkit). To keep the story short: if you bind any TCP port, but
do not listen on it, netstat will not show it at all (the same does
not happen with UDP ports)...
"

Thanks,

On Thu, Feb 17, 2011 at 4:22 PM, dan (ddp) <[email protected]> wrote:
> You'll just have to track down what application is messing with the ports.
> What do the servers do?
> What processes do they run that are short lived and use ports in the
> alerted ranges?
>
> On Wed, Feb 16, 2011 at 3:14 PM, Sebel, Gary M. <[email protected]> wrote:
>> Dan
>>
>> It is the same each run on the system. How do you check to see if the port
>> is open in solaris prior to doing the netstat.  I ask because I have had
>> another person confirm that they also see none of the ports reported as
>> open.
>>
>> So from the runs on the 15th and the 16th the same set of ports are open
>> in the 600/700 range. I am trying to test this out on another solaris
>> server not running zones.
>>
>> Thanks
>> -gary
>>
>> On 2/16/11 2:53 PM, "dan (ddp)" <[email protected]> wrote:
>>
>>>Hi Gary,
>>>Is it always the same port?
>>>OSSEC does 2 checks to see if a port is open, it tries to bind to the
>>>port and checks netstat. If it cannot bind to the port, but netstat
>>>does not see the port as open this alert will be triggered.
>>>So if a process has a port open for the bind check, but closes the
>>>port before the netstat check the alert will be triggered, but will be
>>>a fale positive.
>>>
>>>I don't know enough about solaris w/zones to know if this fp scenario is
>>>likely.
>>>
>>>On Wed, Feb 16, 2011 at 2:45 PM, Sebel, Gary M. <[email protected]> wrote:
>>>> Hello
>>>>
>>>> I am testing OSSEC and have discovered that Solaris servers running with
>>>> local zones are reporting odd messages:
>>>>
>>>> 2011 Feb 16 08:27:25 (first time detected: 2011 Feb 09 14:59:37)
>>>> System Audit: Port '779'(tcp) hidden. Kernel-level rootkit or trojaned
>>>> version of netstat.
>>>>
>>>>
>>>> How is it finding the open ports and reporting on them? I read if it
>>>>sees
>>>> open ports and then notices that they are not open from a netstat it
>>>>will
>>>> report this error.  Just not sure what command or script is reporting
>>>> ports listening on what seems like closed ports.
>>>>
>>>> We have tested with netcat and nmap, confirmed with netstat and lsof
>>>>that
>>>> nothing listening on the port and verified this remotely all results
>>>>show
>>>> the port closed.
>>>>
>>>> Thanks
>>>> -Gary
>>>>
>>>>
>>
>>
>

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