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  3. Trojan.Peacomm

Trojan.Peacomm

Risk Level 2: Low

Discovered:
January 19, 2007
Updated:
January 19, 2007 6:52:29 PM
Also Known As:
Small.DAM [F-Secure], CME-711 [Common Malware Enumeration], Troj/Dorf-Fam [Sophos], Downloader-BAI!M711 [McAfee], TROJ_SMALL.EDW [Trend], W32/Tibs [Norman], Troj/Dorf-J [Sophos], W32/Zhelatin.gen!eml [McAfee], Email-Worm.Win32.Zhelatin [Kaspersky],
Type:
Trojan
Infection Length:
29,347 bytes; 30,720 bytes; 32,387 bytes; 34,816 bytes (varies)
Systems Affected:
Windows 2000, Windows 95, Windows 98, Windows Me, Windows NT, Windows XP
When the Trojan is executed, it drops the following file:
%System%\wincom32.sys

The above file is registered as a new device service driver with the following characteristics:
Display Name: wincom32
Binary Path: %System%\wincom32.sys

The Trojan then creates the following registry subkey to install the above service:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\wincom32

Once loaded the device driver searches for the services.exe process and injects a module into it.

The Trojan may then hide the presence of the device service and its associated file.

It may also reboot the computer without prompt when the threat is first executed.

The Trojan then drops an encrypted list of initial peers into one of the following configuration files:
%System%\peers.ini
%System%\wincom32.ini

It opens and then listens on the following ports, which are used for encrypted communication channels with other peers:
  • UDP port 4000
  • UDP port 7871
  • UDP port 11271

Next, the Trojan registers the compromised computer as a peer in the existing peer-to-peer network, using the Overnet protocol by connecting to the peers specified in the initial peer list.
Note: the Overnet protocol is used by some file sharing applications, however Peacomm uses its own private network.

The peer-to-peer network can then be used by an attacker to retrieve information on what files to download and execute. It also retrieves information of additional peers and updates its own peer list file with the gathered information.

The Trojan may then download and execute the following:
  • 217.107.217.187/game0.exe
  • 81.177.3.169/dir/game1.exe
  • 81.177.3.169/dir/game2.exe
  • 81.177.3.169/dir/game4.exe

The Trojan may be dropped by W32.Mixor.Q@mm. It may also arrive as an attachment to a spammed email.

Currently, the characteristics of the email subject and attachment may include any of the following combinations from a growing list of possibilities:

Subject:
One of the following:
  • 230 dead as storm batters Europe.
  • A killer at 11, he's free at 21 and kill again!
  • British Muslims Genocide
  • Chinese missile shot down Russian aircraft
  • Chinese missile shot down Russian satellite
  • Chinese missile shot down USA aircraft
  • Chinese missile shot down USA satellite
  • Did you open your ecard yet
  • Fidel Castro dead.
  • Naked teens attack home director.
  • New 2008 Year Ecard
  • New 2008 Year Greeting Card
  • New 2008 Year Postcard
  • New Year 2008 Ecard
  • New Year 2008 Greeting Card
  • New Year 2008 Postcard
  • New Year Postcard
  • New Year Postcard
  • Please open your ecard.
  • Radical Muslim drinking enemies's blood.
  • Re: Your text
  • Russian missile shot down Chinese aircraft
  • Russian missile shot down Chinese satellite
  • Russian missile shot down USA aircraft
  • Russian missile shot down USA satellite
  • Saddam Hussein alive!
  • Saddam Hussein safe and sound!
  • Someone is thinking of you! Open your ecard!
  • Someone just sent you a greeting!
  • Someone Just sent you an ecard!
  • This ecard is hillarious!
  • U.S. Secretary of State Condoleezza Rice has kicked German Chancellor Angela Merkel
  • Venezuelan leader: "Let's the War beginning".
  • We have a ecard greeting for you.
  • We have a ecard surprise!
  • We have a ecard surprise!
  • You have just received an ecard.
  • You have one new ecard waiting!
  • Your ecard greeting is available.
  • Your ecard joke is waiting
  • Your ecard joke is waiting!

Attachment:

One of the following:
  • ClickHere.exe
  • e-card.exe
  • familypostcards2008.com
  • FlashPostcard.exe
  • FlashPostcard.exe
  • Full Story.exe
  • FullClip.exe
  • FullNews.exe
  • FullVideo.exe
  • GreetingCard.exe
  • GreetingPostcard.exe
  • happycards2008.com
  • merrychristmasdude.com
  • MoreHere.exe
  • newyearcards2008.com
  • newyearwithlove.com
  • postcard.exe
  • Read More.exe
  • ReadMore.exe
  • uhavepostcard.com
  • Video.exe

Recommendations

Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

  • Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
  • Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
  • Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
  • Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
  • Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
  • Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
  • If a threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
  • Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services.
  • Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
  • Isolate compromised computers quickly to prevent threats from spreading further. Perform a forensic analysis and restore the computers using trusted media.
  • Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.
  • If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
  • For further information on the terms used in this document, please refer to the Security Response glossary.
Writeup By: Masaki Suenaga and Mircea Ciubotariu
Summary| Technical Details| Removal

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