Jan 27, 2012

ssh attack from 1.214.194.114

Port 22 on the local network here was forwarded earlier this week and just yesterday the IP was linked to foran.mooo.com via http://freedns.afraid.org/ (which I came to through the dd-wrt ddns dropdown options)
Tonight, a virtual terminal got spammed with some message I wish I’d thought to copy. It involved the words ssh and root. 

I stopped the ssh deamon and killed all sshd process, grepped auth.log for ‘Accepted password’, and check /root/.bash_history (though any commands would likely have been sent without opening an interactive shell). 
I’ve been rooted!
The earliest entry was at 8am this morning. The last after 7pm.

grep -i ‘accepted password’ /var/log/auth.log*| perl -lne ‘print “$2\t$1” if  m/for (\w+) from ([0-9.]+)/’|sort |uniq -c | sort -nr
      2 1.214.194.114   root  *
      1 94.127.67.61    root  *
      1 221.239.81.4    root  +
      1 221.207.229.6   root +
      1 218.240.44.249  root *
      1 217.148.218.74  root +

* have many attempts
+ only one connection, know correct root password
Russia, South Korea, and China represented.

I checked /etc/passwd, /etc/rc.* and ls -tlc {,/usr/}{/bin/,/sbin/}. All seem okay. 
ps axo cmd,users appears normal. ~/.ssh/authorized_keys are all trusted. 
 nmap localhost is as expected. there are no new jobs in crontab.
It looks like the harm is only that a few people know I forgot to change my weak root password when I opened up the box.

I fixed that. 
I disabled root login and only allow access via publickey,

/etc/ssh/sshd_config
PermitRootLogin No
PasswordAuthentication no
ChallengeResponseAuthentication no

 
In the most recent attack, over 3000 attempts with more than 12 hundred user names. Some were probed more than others. After root, test and oracle were accounts thought to most likely exist, and receive the most attention.
 
function searchIP() { 
 perl -lne “print \$2 if m/(user|for) (\w+) from $1 /” /var/log/auth.log* 
}
 
searchIP 1.214.194.114|wc -l
3429

searchIP 1.214.194.114 |sort -u|wc -l
1269
searchIP 1.214.194.114 |sort |uniq -c|sort -nr | tee >(head -n5 1>&2) |tail -n3
     1087 root
     45 test
     28 oracle
     23 tester
     22 info
     22 guest
      1 gaby
      1 gabriell
      1 

Earlier attacks applied less force. But were equally successful.

searchIP 218.240.44.249 |sort |uniq -c|sort -nr 
    316 root
      1 router
searchIP 94.127.67.61 |wc -l
713
  
searchIP 94.127.67.61 |sort |uniq -c |sort -nr | tee >(head -n5 1>&2) | tail -n3
    394 oracle
    206 root
    140 admin
     56 asterisk
      1 string
      1 ftp
      1 dbus

Picking on 1.214.194.114

nmap -A -T4 1.214.194.114
PORT     STATE    SERVICE      VERSION
21/tcp   open     ftp          vsftpd 2.0.5
22/tcp   open     ssh          OpenSSH 4.3 (protocol 2.0)
| ssh-hostkey: 1024 5f:03:2f:d1:a0:74:be:e9:94:9a:fc:f1:88:66:a9:7a (DSA)
|_2048 22:75:08:79:7b:e2:4f:19:15:0a:39:12:7c:78:af:b4 (RSA)
80/tcp   open     http         Apache httpd 2.2.3 ((CentOS))
|_http-title: UBI\xEB\x84\xA4\xED\x8A\xB8\xEC\x9B\x8C\xED\x81\xAC
|_http-methods: No Allow or Public header in OPTIONS response (status code 200)
|_http-favicon: 
111/tcp  open     rpcbind      2 (rpc #100000)
135/tcp  filtered msrpc
139/tcp  filtered netbios-ssn
445/tcp  filtered microsoft-ds
1700/tcp filtered mps-raft
1720/tcp filtered H.323/Q.931
Service Info: OS: Unix
 

The host http is in Korean.
Clicking around http://1.214.194.114 eventually directs to www.ubipc.co.kr
I thought the IP is a clone of ubipc for phishing. But
 
ping www.ubipc.co.kr
PING www.ubipc.co.kr (1.214.194.114) 56(84) bytes of data.

It appears the attach came from the registered domain.
Domain Name : ubipc.co.kr
Registrant : UBInetwork
Administrative Contact(AC) : UBInetwork
AC E-Mail : kaf551@naver.com
Registered Date : 2011. 12. 27.
Last updated Date : 2011. 12. 27.
Expiration Date : 2013. 12. 27.
Publishes : N
Authorized Agency : Whois Corp.(http://whois.co.kr)

I sent an email to the AC.  

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