RE: Weird SSH attack last night and this morning (still ongoing)

I've been there. Sleep is good.

Though you did remind me with your null attack comment to get off my butt
and capture the packets to see if it's a specific hole trying to be
exploited and not just a brute force password run.

--
Erin Carroll
Moderator, SecurityFocus pen-test mailing list
amoeba_at_amoebazone.com
"Do Not Taunt Happy-Fun Ball"
-----Original Message-----
From: Robert Taylor [mailto:rjamestaylor_at_gmail.com] 
Sent: Wednesday, May 07, 2008 11:24 AM
To: Erin Carroll
Cc: 'Gary Baribault'; incidents_at_securityfocus.com
Subject: Re: Weird SSH attack last night and this morning (still ongoing)
Good points.
I plead exhaustion for missing the key differentiator of this attack :  
one attempt at root (likely the null password attack, as a guess).  
Reason for my tiredness? I'm a third shift admin.
Thank you for the clarification.
On May 7, 2008, at 1:15 PM, Erin Carroll wrote:
> Robert,
>
> I agree that this kind of traffic/attack is extremely common. The only
> notable thing about this one is the very slow attack interval  
> perceived by
> the individual targets. Instead of hammering away at a single target  
> it
> looks like a botnet which is cycling through a large list of targets  
> to
> spread the attack around and more likely sneak in under the radar.  
> That way
> the botnet can leverage its size to run thousands of attacks  
> simultaneously
> but limit the risk of alerting the individual targets since each  
> destination
> is hit with attempts in a small trickle. This method of attack is  
> not so
> common.
>
> It's easy to see or be alerted on the defense side of hundreds or  
> thousands
> of failed attempts but a couple an hour from all different IP's?  
> Fairly easy
> to imagine this slipping past most automated defense or threshold- 
> based
> protections alerts for organizations. Fail2ban, denyhosts, and other  
> ways of
> automating response need the threshold to be reached to blackhole/ 
> null the
> attacker source. This attack pattern seems explicitly designed to  
> bypass
> those types of controls which is what makes it interesting.
>
>
> --
> Erin Carroll
> Moderator, SecurityFocus pen-test mailing list
> amoeba_at_amoebazone.com
> "Do Not Taunt Happy-Fun Ball"
>
>
>
>
>
>
> -----Original Message-----
> From: Robert Taylor [mailto:rjamestaylor_at_gmail.com]
> Sent: Wednesday, May 07, 2008 10:04 AM
> To: Gary Baribault
> Cc: incidents_at_securityfocus.com
> Subject: Re: Weird SSH attack last night and this morning (still  
> ongoing)
>
> It's extremely common to have these scans.
>
>
http://robotterror.com/site/wiki/mitigating_brute_force_password_attacks_wit
> h_pam_abl
>
> That's a link to my blog. I'm a Linux System Admin at a major hosting
> company; this is something I see nightly. Usually, though, I see hits
> on the order of thousands per hour before I get worried.
>
>
> On May 7, 2008, at 7:27 AM, Gary Baribault wrote:
>
>> I don't know what is going on last night and this morning ... I have
>> three Linux servers facing the Internet, two on cable modems and
>> another on a static IP/commercial connection and this last one is a
>> gateway to a Web/FTP/SMTP/Pop3/NTP Linux based system.
>>
>> I have DenyHosts installed on all three and have blocked about 75
>> attempts ..  from known compromised adresses .. The log shows
>> (obviously) that there where even more attempts from adresses that
>> are unknown to DenyHosts but there was only one login attemps per
>> adress and it was with the Root account .. which is obviously
>> blocked in my sshd config ..
>>
>> Of the three machines, one of them only had about 10 attempts, but
>> the other two had about 200 attempts .. all of them with only 1 try
>> with the user Root ..
>>
>> Is any one else seing this? or am I being targeted? This is still
>> going on now .. and it started arround 10:00 last night GMT+4
>>
>> -- 
>> Gary Baribault
>> Courriel: gary_at_baribault.net
>> GPG Key: 0x4346F013
>> GPG Fingerprint: BCE8 2E6B EB39 9B23 6904 1DF4 C4E6 2CF7 4346 F013
>>
>