[Snort-users] Unable to run Snort in IPS mode

Seth Art sethsec at ...11827...
Tue Feb 23 10:15:01 EST 2010


Is the virtual snort actually inline, or is it dropping a COPY of the
traffic?  You can test this with some iptables rules.  Block the
traffic with some FW rules on the snort box and see if the traffic
STILL gets to the destination.

-Seth

On Tue, Feb 23, 2010 at 9:29 AM, Sharma, Ashish <ashish.sharma3 at ...6440...> wrote:
> Nigel,
>
> No success :(
>
> My machine is Fedora Core 10 virtual machine, running on sun virtual Box.
>
> My rules in 'local.rules' are as:
>
> 'drop tcp any any -> 16.150.17.4 80 (msg: "Test web activity";sid:1000001;)
> drop icmp any any -> 16.150.17.4 any (msg: "Test ping activity";sid:1000002;)'
>
> I am running 'snort' by this command:
>
> 'snort -k none -A console -Q -c /etc/snortIDSMode/snort.conf -i eth1 -l /var/log/snort'
>
> Console output is as:
>
> ' 02/23-19:57:13.288720  [Drop] [**] [1:1000001:0] Test web activity [**] [Priority: 0] {TCP} 16.213.0.37:13530 -> 16.150.17.4:80
> 02/23-19:57:13.288812  [Drop] [**] [1:1000001:0] Test web activity [**] [Priority: 0] {TCP} 16.213.0.37:13402 -> 16.150.17.4:80
> 02/23-19:57:47.034571  [Drop] [**] [1:1000002:0] Test ping activity [**] [Priority: 0] {ICMP} 16.150.18.130 -> 16.150.17.4'
>
> Put packets are not getting dropped and replies to above request are being received successfully. This should not happen :( right.
>
> With regards
> Ashish Sharma
>
>
> -----Original Message-----
> From: Nigel Houghton [mailto:nhoughton at ...1935...]
> Sent: Tuesday, February 23, 2010 7:00 PM
> To: Sharma, Ashish
> Cc: Snort Users List
> Subject: Re: [Snort-users] Unable to run Snort in IPS mode
>
> On Tue, Feb 23, 2010 at 2:15 AM, Sharma, Ashish <ashish.sharma3 at ...14781....> wrote:
>> Nigel,
>>
>> No success with your suggested idea.
>>
>> Attached is my 'local.rules' file.
>>
>> My uncommented rule is as:
>> 'drop tcp any any -> 16.150.17.4 80 (msg: "Test web activity";sid:1000001;)'
>>
>> I launch my 'snort' with the following command:
>>
>> 'snort -A console -Q -c /etc/snortIDSMode/snort.conf -i eth1 -l /var/log/snort'
>>
>> Now whenever I try to access a web page hosted on a web server on the same machine (on which snort is hosted), I get following kind of console output:
>>
>> ' 02/23-12:28:04.537751  [Drop] [**] [1:1000001:0] Test web activity [**] [Priority: 0] {TCP} 16.213.0.37:5763 -> 16.150.17.4:80
>> 02/23-12:28:04.538713  [Drop] [**] [1:1000001:0] Test web activity [**] [Priority: 0] {TCP} 16.213.0.37:5763 -> 16.150.17.4:80
>> 02/23-12:28:04.935699  [Drop] [**] [1:1000001:0] Test web activity [**] [Priority: 0] {TCP} 16.213.0.37:5763 -> 16.150.17.4:80
>> 02/23-12:28:05.263633  [Drop] [**] [1:1000001:0] Test web activity [**] [Priority: 0] {TCP} 16.213.0.37:5763 -> 16.150.17.4:80'
>>
>> Here I am able to access my web page from any other foreign machine, but this should not happen with 'Drop' rule of this kind , I should not be able to access my web page in first place when snort is running in 'inline' mode.
>>
>> Moreover I had to comment other 'reject' and 'sdrop' rules since 'snort' fails to identify them (Please look into my first message for console output for this error).
>>
>> Thanks
>> Ashish Sharma
>>
>>
>> -----Original Message-----
>> From: Nigel Houghton [mailto:nhoughton at ...1935...]
>> Sent: Monday, February 22, 2010 9:16 PM
>> To: Sharma, Ashish
>> Cc: Snort Users List
>> Subject: Re: [Snort-users] Unable to run Snort in IPS mode
>>
>> On Mon, Feb 22, 2010 at 9:22 AM, Sharma, Ashish <ashish.sharma3 at ...14783.....> wrote:
>>> Nigel,
>>>
>>> One of my drop rules in 'local.rules' is of following type:
>>> 'drop icmp any any -> xxx.xxx.xxx.xxx any (msg: "Test ping activity";sid:1000002;)'
>>>
>>> Here my intention is to drop any packet that is received for ICMP ping activity, but actually when I run my 'snort',
>>> And 'Ping' on the destination machine only alerts are logged and I receive the response of my 'Ping' command too.
>>>
>>> But I expect this should not happen with 'drop' rule, no response should be received for this case.
>>>
>>> Thanks
>>> Ashish Sharma
>>>
>>> -----Original Message-----
>>> From: Nigel Houghton [mailto:nhoughton at ...1935...]
>>> Sent: Monday, February 22, 2010 7:42 PM
>>> To: Sharma, Ashish
>>> Cc: Snort Users List
>>> Subject: Re: [Snort-users] Unable to run Snort in IPS mode
>>>
>>> On Mon, Feb 22, 2010 at 8:37 AM, Sharma, Ashish <ashish.sharma3 at ...14784......> wrote:
>>>> Rmkml,
>>>>
>>>> Please find attached my 'local.rules' file.
>>>>
>>>> Thanks
>>>> Ashish Sharma
>>>>
>>>> -----Original Message-----
>>>> From: rmkml [mailto:rmkml at ...953...]
>>>> Sent: Monday, February 22, 2010 6:49 PM
>>>> To: Sharma, Ashish
>>>> Cc: rmkml at ...953...
>>>> Subject: RE: [Snort-users] Unable to run Snort in IPS mode
>>>>
>>>> ok thx you Sharma,
>>>> could you send local.rules please?
>>>> Regards
>>>> Rmkml
>>>>
>>>>
>>>> On Mon, 22 Feb 2010, Sharma, Ashish wrote:
>>>>
>>>>> Rmkml,
>>>>>
>>>>> First of all thanks for helping.
>>>>>
>>>>> I don't think there is any problem with command formatting or 'RULE_PATH' variable error.
>>>>>
>>>>> Reason being that when I comment out the 'reject' and 'sdrop' rules from 'local.rules' file and only 'drop' rules are there, then 'Snort' is able to run fine and alerts are generated and logged.
>>>>>
>>>>> For your reference my 'Snort.conf' is attached.
>>>>>
>>>>> Thanks for helping again.
>>>>>
>>>>> Ashish Sharma
>>>>>
>>>>> -----Original Message-----
>>>>> From: rmkml [mailto:rmkml at ...953...]
>>>>> Sent: Monday, February 22, 2010 5:15 PM
>>>>> To: Sharma, Ashish
>>>>> Cc: rmkml at ...953...
>>>>> Subject: Re: [Snort-users] Unable to run Snort in IPS mode
>>>>>
>>>>> Hi Sharma,
>>>>> you start snort with cmd line:
>>>>>  'snort -A console -Q -c /etc/snort /snort.conf -i eth1 -l /var/log/snort'
>>>>> please remove space like ... -c /etc/snort/snort.conf ...
>>>>> on your snort.conf, what is RULE_PATH variable contains please? or send
>>>>> snort.conf...
>>>>> Regards
>>>>> Rmkml
>>>>>
>>>>>
>>>>> On Mon, 22 Feb 2010, Sharma, Ashish wrote:
>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> I have a fedora core 10 virtual machine running on a sun virtual box.
>>>>>>
>>>>>> I am trying to run Snort on this machine in IPS mode.
>>>>>>
>>>>>> I followed the following steps (I had already installed the prerequisites for Snort IPS):
>>>>>>
>>>>>> 1. Downloaded 'snort-2.8.5.2.tar.gz'
>>>>>> 2. Extracted the binaries.
>>>>>> 3. did './configure --enable-inline'
>>>>>> 4. did 'make'
>>>>>> 5. did 'make install'
>>>>>> 6. copied snort rules and snort conf at appropriate location.
>>>>>> 7. executed the following command :
>>>>>> 'snort -A console -Q -c /etc/snort /snort.conf -i eth1 -l /var/log/snort'
>>>>>> 8. Snort launches with the traces :
>>>>>>
>>>>>> Enabling inline operation
>>>>>> Running in IDS mode
>>>>>>
>>>>>> --== Initializing Snort ==--
>>>>>> Initializing Output Plugins!
>>>>>> Initializing Preprocessors!
>>>>>> ..................................
>>>>>>
>>>>>> Initializing rule chains...
>>>>>> ERROR: /etc/snortIDSMode/rules /local.rules(10 ) Unknown rule type: reject.
>>>>>> Fatal Error, Quitting..
>>>>>>
>>>>>> 8. As you can see I have a test rule in local.rule that have a 'reject' rule in it but snort is not accepting it, same is the case for 'sdrop' rule also.
>>>>>>
>>>>>> 9. What is the problem , please help!!!!!
>>>>>>
>>>>>> What should I do in all to let my Snort run in IPS mode
>>>>>>
>>>>>> Thanks in advance
>>>>>>
>>>>>> Ashish Sharma
>>>>>>
>>>>>
>>>>
>>>> ------------------------------------------------------------------------------
>>>> Download Intel® Parallel Studio Eval
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>>>
>>>
>>> You have compiled Snort with --enable-inline. Your snort.conf looks
>>> fine. The rules you have need to use the "drop" keyword instead of
>>> "alert" so that they will drop the traffic in inline mode.
>>>
>>> So your two rules would become:
>>>
>>> drop tcp any any -> 16.150.17.4 25 (msg: "Test activity"; sid:1000003;)
>>> drop tcp any any -> 16.150.17.4 3310 (msg: "Test activity"; sid:1000004;)
>>>
>>> --
>>> Nigel Houghton
>>> Head Mentalist
>>> SF VRT
>>> http://vrt-sourcefire.blogspot.com && http://labs.snort.org/
>>>
>>
>>
>> Your drop rule is commented out, so it is not active. Please try what
>> I told you to try and report back. Thanks.
>>
>> --
>> Nigel Houghton
>> Head Mentalist
>> SF VRT
>> http://vrt-sourcefire.blogspot.com && http://labs.snort.org/
>>
>
>
> Now we are getting somewhere. Since your snort installation is on the
> same machine you are sending packets to, try adding the "-k none"
> option to the command line. See if that fixes your problem and report
> back.
>
> --
> Nigel Houghton
> Head Mentalist
> SF VRT
> http://vrt-sourcefire.blogspot.com && http://labs.snort.org/
>
> ------------------------------------------------------------------------------
> Download Intel® Parallel Studio Eval
> Try the new software tools for yourself. Speed compiling, find bugs
> proactively, and fine-tune applications for parallel performance.
> See why Intel Parallel Studio got high marks during beta.
> http://p.sf.net/sfu/intel-sw-dev
> _______________________________________________
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