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Discovered: October 31, 2007
Updated: October 31, 2007 11:28:12 PM
Also Known As: WORM_ZHELATI.AXD [Trend], WORM_NUWAR.ARJ [Trend], Troj/DTibs-TJ [Sophos]
Type: Trojan, Virus
Infection Length: Varies
Systems Affected: Windows

Trojan.Peacomm.D is a Trojan horse that gathers system information and email addresses from the compromised computer.

Note: The Peacomm family of Trojans is also commonly known as the "Storm" Trojan.

Antivirus Protection Dates

  • Initial Rapid Release version October 31, 2007
  • Latest Rapid Release version May 07, 2019 revision 006
  • Initial Daily Certified version November 01, 2007 revision 016
  • Latest Daily Certified version May 07, 2019 revision 008
  • Initial Weekly Certified release date November 07, 2007

Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

Technical Description

The Trojan may be downloaded as one of the following files or installed through accessed Web exploits:

When the Trojan is executed, it copies itself to the following location:

It then creates the following registry entry so that it runs every time Windows starts:
HKEY_CURRENT_USER\Microsoft\Windows\CurrentVersion\Run\"noskrnl" = "%Windir%\noskrnl.exe"

It modifies the following registry value to disable the Windows Firewall:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\"Start" = "4"

It will try to execute the following external program, if present:
w32tm.exe /config /synffromflags:manual /,
w32tm.exe /config /update

Note: This external program is a legitimate tool used for time synchronization.

Next, the Trojan drops an embedded kernel driver to the following location:
%System%\noskrnl.sys (detected as Trojan.Peacomm.D)

It creates the following registry subkey to register the driver and next it loads the driver:

The driver uses Rootkit functionalities to hide itself. It hooks the following
system functions to hide files and registry keys that begin with noskrnl:
  • ZwEnumerateValueKey
  • ZwQueryDirectoryFile

It uses rootkit techniques to hide the following running process:

The rootkit will end the following security-related programs every time they are executed:
  • avp.exe
  • avpm.exe
  • avz.exe
  • bdmcon.exe
  • bdss.exe
  • ccapp.exe
  • ccevtmgr.exe
  • cclaw.exe
  • ccpxysvc.exe
  • fsav32.exe
  • fsbl.exe
  • fsm32.exe
  • gcasserv.exe
  • iao.exe
  • icmon.exe
  • inetupd.exe
  • issvc.exe
  • kav.exe
  • kavss.exe
  • kavsvc.exe
  • klswd.exe
  • livesrv.exe
  • mcshield.exe
  • msssrv.exe
  • nod32krn.exe
  • nod32ra.exe
  • pavfnsvr.exe
  • rtvscan.exe
  • savscan.exe

The rootkit will disable the following security-related drivers:
  • bc_hassh_f.sys
  • bc_ip_f.sys
  • bc_ngn.sys
  • bc_pat_f.sys
  • bc_prt_f.sys
  • bc_tdi_f.sys
  • bcfilter.sys
  • bcftdi.sys
  • filtnt.sys
  • mpfirewall.sys
  • sandbox.sys
  • vsdatant.sys
  • watchdog.sys
  • zclient.exe

Next, the threat creates the following Windows events to ensure that only one copy of the Trojan is running and to communicate with the kernel driver:
  • ExitEvent
  • idlock.temp0995499F553D877887444EC7A
  • Iu6Uu3wJJHF%WYHS
  • xInstalled

It drops an encrypted list of initial peers to the following configuration file that is hidden by the rootkit:

It registers the compromised computer as a peer in the existing file-sharing network, using a custom
encrypted version of 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 peer-to-peer network can then be used by a remote attacker as a back door to gain access to and run specific commands on the compromised computer. The Trojan can perform the following actions:
  • Send spam emails by using its own SMTP engine
  • Gather system information from the compromised computer, such as computer name, OS version, country, and IP address
  • Perform distributed denial of service (DDoS) attacks
  • Download and execute remote files
  • Update itself

It also tries to spread by copying itself to folders on local, remote and removable drives if the directories contain an executable file. It copies itself with the following file name:
%DriveLetter%\[FOLDER NAME]\_install.exe

It may search for files with the following extensions:
  • .htm
  • .html
  • .php

It injects an IFRAME tag string into all of the files that it finds. It has been reported that the IFRAME tag string injected is similar to:
<iframe src=[MALICIOUS SITE] width="1" height="1" alt="Uw8bLlKjsi3HqXs"></iframe>

At the time of writing, [MALICIOUS SITE] has been reported to be one of the following websites:
  • [http://][REMOVED]
  • [http://][REMOVED]

The Trojan is also able to connect to remote FTP servers chosen by the attacker and perform file upload and download operations.

It can change DNS servers of the compromised machine by modifying the following value:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TcpIp\Parameters\Interfaces\[CLSID]\"NamServer" = "[DNS SERVER]"

Note: [DNS SERVER] is an IP address of a DNS server chosen by the attacker.

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

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

The Trojan steals information from the following registry subkey which contains a unique ID for the computer on the file-sharing network:


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.


The following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

  1. Disable System Restore (Windows Me/XP).
  2. Update the virus definitions.
  3. Run a full system scan.
  4. Delete any values added to the registry.

For specific details on each of these steps, read the following instructions.

1. To disable System Restore (Windows Me/XP)
If you are running Windows Me or Windows XP, we recommend that you temporarily turn off System Restore. Windows Me/XP uses this feature, which is enabled by default, to restore the files on your computer in case they become damaged. If a virus, worm, or Trojan infects a computer, System Restore may back up the virus, worm, or Trojan on the computer.

Windows prevents outside programs, including antivirus programs, from modifying System Restore. Therefore, antivirus programs or tools cannot remove threats in the System Restore folder. As a result, System Restore has the potential of restoring an infected file on your computer, even after you have cleaned the infected files from all the other locations.

Also, a virus scan may detect a threat in the System Restore folder even though you have removed the threat.

For instructions on how to turn off System Restore, read your Windows documentation, or one of the following articles:

Note: When you are completely finished with the removal procedure and are satisfied that the threat has been removed, reenable System Restore by following the instructions in the aforementioned documents.

For additional information, and an alternative to disabling Windows Me System Restore, see the Microsoft Knowledge Base article: Antivirus Tools Cannot Clean Infected Files in the _Restore Folder (Article ID: Q263455).

2. To update the virus definitions
Symantec Security Response fully tests all the virus definitions for quality assurance before they are posted to our servers. There are two ways to obtain the most recent virus definitions:
  • Running LiveUpdate, which is the easiest way to obtain virus definitions.

    If you use Norton AntiVirus 2006, Symantec AntiVirus Corporate Edition 10.0, or newer products, LiveUpdate definitions are updated daily. These products include newer technology.

    If you use Norton AntiVirus 2005, Symantec AntiVirus Corporate Edition 9.0, or earlier products, LiveUpdate definitions are updated weekly. The exception is major outbreaks, when definitions are updated more often.

  • Downloading the definitions using the Intelligent Updater: The Intelligent Updater virus definitions are posted daily. You should download the definitions from the Symantec Security Response Web site and manually install them.

The latest Intelligent Updater virus definitions can be obtained here: Intelligent Updater virus definitions . For detailed instructions read the document: How to update virus definition files using the Intelligent Updater .

3. To run a full system scan
  1. Start your Symantec antivirus program and make sure that it is configured to scan all the files.

    For Norton AntiVirus consumer products: Read the document: How to configure Norton AntiVirus to scan all files.

    For Symantec AntiVirus Enterprise products: Read the document: How to verify that a Symantec Corporate antivirus product is set to scan all files.

  2. Run a full system scan.
  3. If any files are detected, follow the instructions displayed by your antivirus program.
Important: If you are unable to start your Symantec antivirus product or the product reports that it cannot delete a detected file, you may need to stop the risk from running in order to remove it. To do this, run the scan in Safe mode. For instructions, read the document, How to start the computer in Safe Mode . Once you have restarted in Safe mode, run the scan again.

After the files are deleted, restart the computer in Normal mode and proceed with the next section.

Warning messages may be displayed when the computer is restarted, since the threat may not be fully removed at this point. You can ignore these messages and click OK. These messages will not appear when the computer is restarted after the removal instructions have been fully completed. The messages displayed may be similar to the following:

Title: [FILE PATH]
Message body: Windows cannot find [FILE NAME]. Make sure you typed the name correctly, and then try again. To search for a file, click the Start button, and then click Search.

4. To delete the value from the registry
Important: Symantec strongly recommends that you back up the registry before making any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify the specified subkeys only. For instructions refer to the document: How to make a backup of the Windows registry .
  1. Click Start > Run.
  2. Type regedit
  3. Click OK.

    Note: If the registry editor fails to open the threat may have modified the registry to prevent access to the registry editor. Security Response has developed a tool to resolve this problem. Download and run this tool, and then continue with the removal.
  4. Navigate to and delete the following entries:

    HKEY_CURRENT_USER\Microsoft\Windows\CurrentVersion\Run\"noskrnl" = "%Windir%\noskrnl.exe"

  5. Navigate to and delete the following entries:


  6. Restore the following registry entries to their original values, if required:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TcpIp\Parameters\Interfaces\[CLSID]\"NamServer" = "[DNS SERVER]"
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\"Start" = "4"

  7. Exit the Registry Editor.

    Note: If the risk creates or modifies registry subkeys or entries under HKEY_CURRENT_USER, it is possible that it created them for every user on the compromised computer. To ensure that all registry subkeys or entries are removed or restored, log on using each user account and check for any HKEY_CURRENT_USER items listed above.

Writeup By: Elia Florio