full-disclosure - [VulnDiscuss] Re: Automated SSH login attempts?

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From: pauls at utdallas.edu (Paul Schmehl)
Subject: [VulnDiscuss] Re: Automated SSH login
 attempts?

--On Monday, July 26, 2004 03:29:56 PM -0400 RBabb 
<rob_mailing_lists@...bb.net> wrote:
>
> This makes me feel better. I thought it odd that so many machines were
> hitting my ssh server. I even blocked it at the firewall for a day or so.
> Is anyone talking on what the bot system was that allowed them to
> automate this? It seemed that as soon as 1 got it so did a whole bunch
> more so obviously people are distributing lists of IP's for potential SSH
> access.
>
That's not obvious at all.  In our case, they're hitting IPs in sequential 
order, so it looks (to us) more like a "brute force" attempt rather than 
the targeting of hosts that are specifically running sshd.

> I'm not real sure on who to contact for these machines, but here are all
> the ones that have hit me. Mostly seem to be Asian so far.
>
> Jul 25 19:48:40 server sshd[55910]: Failed password for illegal user test
> from 212.4.172.123 port 56843 ssh2
> Jul 25 19:48:42 server sshd[55915]: Failed password for illegal user
> guest from 212.4.172.123 port 56916 ssh2
> Jul 25 20:37:19 server sshd[57221]: Failed password for illegal user test
> from 210.40.224.10 port 49738 ssh2
> Jul 25 20:37:22 server sshd[57223]: Failed password for illegal user
> guest from 210.40.224.10 port 49756 ssh2
>
[pauls@...49554 pauls]$ dig -x 212.4.172.123

; <<>> DiG 9.2.2-P3 <<>> -x 212.4.172.123
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 123
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 1

;; QUESTION SECTION:
;123.172.4.212.in-addr.arpa.    IN      PTR

;; ANSWER SECTION:
123.172.4.212.in-addr.arpa. 604800 IN   PTR     mail.enet.de.

Since this is a mail server, I would say the odds are *extremely high* that 
it's been compromised and that the owners would greatly appreciate a heads 
up.  (So I've cc'd them.  But these are *your* logs, so *you* should notify 
them as well.

> Jul 24 21:37:50 server sshd[21578]: Failed password for illegal user test
> from 218.244.240.195 port 58900 ssh2
> Jul 24 21:37:53 server sshd[21580]: Failed password for illegal user
> guest from 218.244.240.195 port 58928 ssh2
>
person:       ShouLan Du
address:      Fl./8, South Building, Bridge Mansion, No. 53
country:      CN
phone:        +86-010-83160000
fax-no:       +86-010-83155528
e-mail:       dsl327@...mail.net.cn
nic-hdl:      SD76-AP
mnt-by:       MAINT-CNNIC-AP
changed:      dsl327@...mail.net.cn 20020403
source:       APNIC

> Jul 22 18:23:36 server sshd[38184]: Failed password for illegal user test
> from 216.86.221.113 port 58012 ssh2
> Jul 22 18:23:37 server sshd[38195]: Failed password for illegal user
> guest from 216.86.221.113 port 51509 ssh2
>
;; ANSWER SECTION:
113.221.86.216.in-addr.arpa. 14400 IN   PTR 
adsl-gte-la-216-86-215-113.mminternet.com.

Technical Contact:
      Master, Host  (NC312)             hostmaster@...NTERNET.COM
      3780 Kilroy Airport Way
      Suite 410
      Long Beach, CA 90806
      US
      562-427-0344 fax: 562-427-3622


Paul Schmehl (pauls@...allas.edu)
Adjunct Information Security Officer
The University of Texas at Dallas
AVIEN Founding Member
http://www.utdallas.edu/ir/security/