Re: SIP dictionary attacks

Joe Nall <[email protected]>
Newsgroups gmane.comp.security.firewalls.wizards
Message-ID <[email protected]>
On Apr 2, 2009, at 2:08 PM, Lord Sporkton wrote:

> I'm using openbsd as my firewall, in which there is a connection/time
> feature. I can set it to block any ip that makes X connection with in
> X time. for instance if someone connects to my ssh port more than 3
> times in 30 seconds, they get blocked, since your on sip, you could do
> like say, anyone connecting more than 5 times in 5 minutes gets
> blocked, sip usually doesnt have that many connections, it just
> connects then its up sorta thing.
>
> I believe there is a version of this in iptables, but ive never seen
> it in a hardware firewall.

fail2ban can do this with iptables

joe

>
> That is at least how i solved the problem you face.
>
>
>
> 2009/4/1 Paul D. Robertson <[email protected]>:
>> Well, besides losing my voice which has given me a little time to  
>> catch up
>> on things, one of my problems last week was a successful dictionary  
>> attack
>> against a SIP extension with an eight digit password.
>>
>> Obviously, I've changed the passwords and lengths, but I did want  
>> to make
>> sure folks knew that there were active attacks out there, and they're
>> obviously scanning for systems randomly, since the system in  
>> question was
>> only recently moved to a new IP address space.  The initial scans  
>> came
>> from a box in China (surprise!)
>>
>> Anyway, all I've found for blocking outside of static IP address  
>> ranges is
>> a bunch of check the logs and react stuff for Linux.  I'm starting to
>> think IPS might actually have a use- time to Google for snort  
>> inline sutff
>> I suppose.
>>
>> Attackers made about calls out to people telling them they owed  
>> money.
>> Calls were initiated from Europe, Asia and the US.  Likely from
>> compromised hosts.
>>
>> Paul
>> -----------------------------------------------------------------------------
>> Paul D. Robertson      "My statements in this message are personal  
>> opinions
>> [email protected]       which may have no basis whatsoever in fact."
>>           Moderator: Firewall-Wizards mailing list
>>           Art: http://PaulDRobertson.imagekind.com/
>>
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