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1,708 failed logins attacks from Russia, China, & Iran

Posted on 2011-09-09
Medium Priority
Last Modified: 2012-05-12
I noticed 1,708 failed logins attacks from Russia ( &, China ( & Iran ( in the Security Logs since 9/8/11 at 9:59 pm up to present.

How are they able to knock on the door? Firewall should be denying them before hitting the server? What types of countermeasures should I initiate?

Microsoft SBS2k3 Security Best Practices was followed, except for renaming all admin accounts, which was just done this morning (http://technet.microsoft.com/en-us/library/cc747484(WS.10).aspx). I have noticed RealVNC on several machines that were installed by our software vendor for remote support. Shares were already all locked down. Changed the LAN IP addresses for everything: firewall gateways (WLAN & LAN), server, all reservations, and devices. Passwords do not expire but do meet the Best Practices listed above: complexity, length, lockout policy (60m, 4, 60m).

The environment:
(1) SBS 2k3, SP2, domain – all patched.
(25) Windows XP, SP3 – 60% patched. The 40% may need the most recent patches only.
(1) SonicWALL TZ 170 w/CGSS (Comprehensive Gateway Security Suite).
ESET Business ERAC – all def. current/no infections.
SuperAntiSpyware – all def. current/no infections.

IPs logged: - Iran & - Russia - China

1638, 2655, 2793, 2766, 2738, 2606, 2581, 7077, etc.

Example attack below:

Event Type:      Failure Audit
Event Source:      Security
Event Category:      Logon/Logoff
Event ID:      529
Date:            9/9/2011
Time:            2:07:06 AM
User:            NT AUTHORITY\SYSTEM
Computer:      Server3
Logon Failure:
       Reason:            Unknown user name or bad password
       User Name:      server
       Domain:            theDomain
       Logon Type:      10
       Logon Process:      User32  
       Authentication Package:      Negotiate
       Workstation Name:      Server3
       Caller User Name:      Server3$
       Caller Domain:      theDomain
       Caller Logon ID:      (0x0,0x3E7)
       Caller Process ID:      6356
       Transited Services:      -
       Source Network Address:
       Source Port:      2655
Question by:Blue Street Tech

Accepted Solution

nativevlan earned 1000 total points
ID: 36512771
It sounds like your firewall is not blocking the login attempts.  Reconfigure the firewall block all traffic that is destined for 3389 incoming, unless you need RDP from the internet from certain hosts for some reason. In that case allow only the required IP addresses inbound over RDP.

Expert Comment

ID: 36512885
There is deffintly something not going right with the firewall, are you running the latest firmware for the TZ 170? I believe it is if you are on SonicOS Enhanced. I would as the other user lock down and un-needed ports from outside access. Also place sensitive servers on the guarded LAN and place public facing servers in a DMZ with controlled access. The TZ 170 is an outdated device and does not stand up well against newer more sophisticated attacks. The newer models (NSA series) on firmware 5.8.1 now have a feature to block based on Geo-Location so you can block IPs from specific countries such as Iran, Russia, etc.

Harden your network and you should be OK from most threats.
LVL 77

Assisted Solution

by:Rob Williams
Rob Williams earned 1000 total points
ID: 36513062
>>" have noticed RealVNC on several machines "
Real VNC is very unsecure.

90% of these types of attacks are done through Remote Desktop. Is port 3389 open? In an SBS environment there is no need. Using RWW is much more secure using ports 443 & 4125
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LVL 33

Expert Comment

ID: 36513147
I'm in agreement with suggestions here. What ports are open on your sonicwall WAN > LAN? Also, you might consider looking internally as well. Do you have any devices that might be infected with malicious software giving your network a backdoor? If you have an infected machine then it's possible several hundred or thousand connections are being created LAN > WAN. You can determine this by going to Firewall > Connections or System > Diagnostics > Connections. Whatever devices it is, I'd disconnect it from the network and sanitize it.
LVL 27

Author Comment

by:Blue Street Tech
ID: 36513184
@ALL: Thanks for your quick responses! Checking access rules now. I will post findings shortly.
LVL 27

Author Comment

by:Blue Street Tech
ID: 36514399
@amatson78: Yes, FW has the most recent firmware. Agreed it’s old.  :(  Time for new gear!

@RobWill: I uninstalled 10 Real VNC isntallations – once I did that on top of deleting TS access. The log cleared up.

@digitap: Thanks! I checked the connection monitor - nothing out of the ordinary LAN > WAN.

@ALL: Wow! We had someone working on the FW three days ago and must have enabled TS (*, (LAN),Terminal Services, Allow), cause it was enabled. This was an old rule that should have been deleted not disabled. VPN is exclusively used before TS in this envir. Thanks! Sometimes the most obvious is the most overlooked. I didn’t even check the access rules because “I knew” there was no open ports left to be slaughtered. Lol. :p Thanks again!
LVL 27

Author Closing Comment

by:Blue Street Tech
ID: 36514407
I am awarding points based on first responders, so nativevlan: for suggesting removal of TS (3389) access and RobWill: for suggesting disabling RealVNC installations. Let me know if anyone feels otherwise.

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