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  3. Trojan.Peacomm.C

Trojan.Peacomm.C

Risk Level 2: Low

Discovered:
August 22, 2007
Updated:
August 22, 2007 2:09:36 PM
Also Known As:
WORM_ZHELATI.MAB [Trend],
Type:
Trojan
Infection Length:
114,606 bytes
Systems Affected:
Windows XP, Windows Server 2003, Windows 2000
This Trojan may be downloaded as one of the following files:
  • ecard.exe
  • msdataaccess.exe
  • applet.exe


When the Trojan is executed, it copies itself to the following location:
%Windir%\spooldr.exe

Next, the Trojan drops an embedded kernel driver to the following location:
%System%\spooldr.sys

It then attempts to infect the following legitimate Windows driver with a copy of Trojan.Peacomm!inf:
%System%\drivers\kbdclass.sys

It also attempts to infect the cached copy of the above driver:
%System%\dllcache\kbdclass.sys

The infected driver is also copied to the following locations:
  • %Windir%\LastGood\system32\drivers\kbdclass.sys
  • %System%\Drivers\old5.tmp


The Trojan then ends and waits for the user to restart the computer.

When the computer is restarted, the file kbdclass.sys is loaded.

The infected driver then loads the following file:
%System%\spooldr.sys

The above file injects itself into the following process:
explorer.exe

It also has rootkit functionalities to hide the following process:
spooldr.exe

The rootkit also hides the following files:
  • %System%\spooldr.sys
  • %Windir%\spooldr.ini


It also disables the following security-related software:
  • ZoneAlarm Firewall
  • PC Watchdog Systems
  • Bcfilter Jetico Personal Firewall
  • Outpost Firewall
  • McAfee Anti Spyware
  • McAfee Internet Security Suite
  • FSecure Black Light
  • Kaspersky Anti Virus
  • Symantec Anti Virus
  • BitDefender Anti Virus
  • FSecure Anti Virus
  • Microsoft Anti Spyware
  • InterCheck Monitor
  • NOD32 Anti Virus
  • Panda Anti Virus


The Trojan then checks for the presence of VMWare or VirtualPC. If one of these virtual machines is detected, the Trojan enters an infinite loop and does nothing.

If the above virtual machines are not present, the Trojan creates the following event to ensure that only one copy of the threat is running on the computer:
K8JT6Hnjm$#jui#WWhHHgG

The Trojan then drops an encrypted list of initial peers to the following configuration file:
%Windir%\spooldr.ini

It registers the compromised computer as a peer in the existing file-sharing network, using the Overnet protocol by connecting to the peers specified in the initial peer list. It uses a randomly chosen UDP port to communicate with the other peers.

The file-sharing network can then be used by a remote attacker as a back door to gain access to the compromised computer.

The Trojan then steals operating system information from the compromised computer.

It also harvests email addresses from the computer by searching for files with the following extensions:
  • .wab
  • .txt
  • .msg
  • .htm
  • .shtm
  • .stm
  • .xml
  • .dbx
  • .mbx
  • .mdx
  • .eml
  • .nch
  • .mmf
  • .ods
  • .cfg
  • .asp
  • .php
  • .pl
  • .wsh
  • .adb
  • .tbb
  • .sht
  • .xls
  • .oft
  • .uin
  • .cgi
  • .mht
  • .dhtm
  • .jsp
  • .dat
  • .lst


The Trojan then sends spam emails by using its own SMTP engine.

It does not send emails to email addresses containing the following strings:
  • @microsoft
  • rating@
  • f-secur
  • news
  • update
  • anyone@
  • bugs@
  • contract@
  • feste
  • gold-certs@
  • help@
  • info@
  • nobody@
  • noone@
  • kasp
  • admin
  • icrosoft
  • support
  • ntivi
  • unix
  • bsd
  • linux
  • listserv
  • certific
  • sopho
  • @foo
  • @iana
  • free-av
  • @messagelab
  • winzip
  • google
  • winrar
  • samples
  • abuse
  • panda
  • cafee
  • spam
  • pgp
  • @avp.
  • noreply
  • local
  • root@
  • postmaster@


The Trojan steals information from the following registry subkey, which contains a unique ID for the computer on the file-sharing network:
HKEY_LOCAL_MACHINE\Microsoft\Windows\ITStorage\Finders\"config"

Search for files with the following extensions:
  • .htm
  • .html
  • .php

It then injects an iframe tag into all of the files that it finds. The iframe tag attempts to load malicious .html files in an attempt to spread itself.

The Trojan may then download and execute potentially malicious files on to the compromised computer.

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.
Summary| Technical Details| Removal

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