WORM_RANDON.B

Malware type: Worm

Aliases: Net-Worm.Win32.Randon.an (Kaspersky), W32/Randon.worm.gen (McAfee), IRC Trojan (Symantec), DR/Randon.AN (Avira), Troj/Mirchack-C (Sophos), Backdoor:IRC/Tagbot.A (Microsoft)

In the wild: Yes

Destructive: No

Language: English

Platform: Windows 95, 98, ME, NT, 2000, XP

Encrypted: No

Overall risk rating:

Reported infections:

Damage potential:

High

Distribution potential:

High

Description: 

This worm propagates through Internet Relay Chat (IRC). It also attempts to spread via network shares. It tries to access shares using NetBEUI functions and a list of user names and passwords and drops a copy of itself on successfully accessed share folders.

(Note: NetBEUI [short for NetBios Extended User Interface] is an enhanced version of the NetBIOS protocol. For more information about NetBEUI, click here.)

On execution, it drops several malicious component files, configuration files, user name and password lists, and port lists on the affected system.

This worm also carries backdoor capabilities. It connects to an IRC server and operates as an IRC bot, allowing remote users to issue commands to the affected system, giving them virtual control of the system.

This worm runs on Windows 95, 98, ME, NT, 2000, and XP.

For additional information about this threat, see:

Description created: Oct. 13, 2004 5:42:45 AM GMT -0800


TECHNICAL DETAILS


Size of malware: 1,322,478 Bytes

Initial samples received on: Oct 13, 2004

Related toHKTL_PSEXEC.A, HKTL_HIDEWIN.A

Details:

Component Files

Upon execution, this memory-resident worm drops the following files in the %System%\q45d4e5 folder:

  • Alial
    This file holds certain path information for the worm.

  • APC.exe
    This file is a renamed mIRC client.

  • c.bat
    This batch file executes GER.EXE.

  • Cult.exe
    This file is a process viewer. It is detected by Trend Micro as HKTL_PRCVIEW.B.

  • Emoti.bat
    This batch file is designed to access network shares and is detected as BAT_RANDON.B.

  • Explorx.exe
    This hack tool is used to exploit the Windows LSASS (MS04-011) and the RPC DCOM buffer overflow (MS03-026) vulnerabilities. Trend Micro detects this file as HKTL_RPCLSA.B.

  • FOLDX.EXE
    This hack tool is used to hide windows and is detected as HKTL_HIDEWIN.D.

  • GER.EXE
    This file is designed to edit the registry.

  • HOSTS
    This file is used to overwrite the legitimate Windows HOSTS file to restrict access to certain antivirus sites.

  • L0c0.exe
    This file is a Trojan downloader, detected as TROJ_SMALL.ID.

  • Medo.dl
    This file contains a list of nicknames.

  • Pp1.exe
    This file is a backdoor IRC server, which is detected as BKDR_MOTIVFTP.12.

  • Repcale.exe
    This file is another program that is designed to hide windows. It is detected as HKTL_HIDEWIN.A.

  • Riqa
    This file contains a list of IP ranges.

  • Soundmon.exe
    This file is used to scan ports and is detected as HKTL_XSCAN.B.

  • Titlex.exe
    This program is used to remotely execute programs and is detected as HKTL_PSEXEC.A.

  • x-scancfg.ini
    This file holds configuration data for XSCAN.

  • Yrtsiger.bat
    This batch file uses GER.EXE to add registry keys.

  • Zema
    This file serves as the worm's main IRC script and is detected as IRC_RANDON.J.

  • Plugin\090-ntpass.xpn
    This file is another port scanner and is detected as HKTL_XSCAN.A.

This worm also drops various configuration files, user name and password lists, and port lists, in the same folder. Some of these files are as follows:

  • Dual.exe
  • dat\config.ini
  • Dat\easy_user.dic
  • Dat\language.ini
  • Dat\nt_pass.dic
  • Dat\nt_user.dic
  • Dat\os.finger
  • Dat\port.ini
  • Dat\rpc.ini

Autostart Techniques

To ensure that it runs at every Windows startup, this worm creates the following autorun registry entries:

HKEY_LOCAL_MACHINE/Software/Microsoft/Windows/
CurrentVersion/Run
INFO DATA = %System%\q45d4e5\apc.exe

HKEY_LOCAL_MACHINE/Software/Microsoft/Windows/
CurrentVersion/RunServices
INFO DATA = %System%\q45d4e5\apc.exe

HKEY_CURRENT_USER/Software/Microsoft/Windows/
CurrentVersion/Run
INFO DATA = %System%\q45d4e5\apc.exe

HKEY_CURRENT_USER/Software/Microsoft/Windows/
CurrentVersion/RunServices
INFO DATA = %System%\q45d4e5\apc.exe

It also creates the following registry keys, which it uses to store some date:

HKEY_LOCAL_MACHINE\Software\Classes\irc

HKEY_LOCAL_MACHINE\Software\Classes\ChatFile

HKEY_LOCAL_MACHINE\Software\Classes\.cha

HKEY_LOCAL_MACHINE\Software\Classes\.chat

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\ CurrentVersion\Uninstall\mIRC

These registry keys are more likely the result of the installation of the hacked mIRC client, rather than intentionally designed.

Propagation

This worm program propagates through IRC (Internet Relay Chat). It also utilizes NetBEUI functions to spread through network shares. Apart from NetBEUI functions, it also uses a list of user names and passwords to access network shares, where it attempts to drop copies of itself.

Backdoor Capabilities

This worm also has backdoor capabilities. It connects to an IRC server and operates as an IRC bot, allowing remote users to issue commands to the affected system, giving them virtual control of the affected system.

Some of the commands it executes are as follows:

  • Create a BNC remote IRC server
  • Download a file from the Internet
  • Open an FTP server
  • Launch basic IRC commands
  • Flood other IRC users
  • Launch SYN DOS attack
  • Scan for ports



Analysis by: Marc Sison


SOLUTION


Minimum scan engine version needed: 6.810

Pattern file needed: 2.199.06

Pattern release date: Oct 13, 2004


Important note: The "Minimum scan engine" refers to the earliest Trend Micro scan engine version guaranteed to detect this threat. However, Trend Micro strongly recommends that you update to the latest version in order to get comprehensive protection. Download the latest scan engine here.

Solution:

Terminating the Malware Program

This procedure terminates the running malware process.

  1. Open Windows Task Manager.
    � On Windows 95, 98, and ME, press
    CTRL%20ALT%20DELETE
    � On Windows NT, 2000, and XP, press
    CTRL%20SHIFT%20ESC, then click the Processes tab.
  2. In the list of running programs*, locate the process:
    APC.EXE
  3. Select the malware process, then press either the End Task or the End Process button, depending on the version of Windows on your system.
  4. To check if the malware process has been terminated, close Task Manager, and then open it again.
  5. Close Task Manager.

*NOTE: On systems running Windows 95, 98, and ME, Windows Task Manager may not show certain processes. You can use a third party process viewer such as Process Explorer to terminate the malware process. Otherwise, continue with the next procedure, noting additional instructions.

Removing Autostart Entries from the Registry

Removing autostart entries from the registry prevents the malware from executing at startup.

  1. Open Registry Editor. Click Start>Run, type REGEDIT, then press Enter.
  2. In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>Software>Microsoft>
    Windows>CurrentVersion>Run
  3. In the right panel, locate and delete the entry:
    INFO DATA = %System%\q45de5\apc.exe
    (Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 95, 98 and ME, C:\WINNT\System32 on Windows NT and 2000, and C:\Windows\System32 on Windows XP.)
  4. In the left panel, double-click the following:
    HKEY_LOCAL_MACHINE>Software>Microsoft>
    Windows>CurrentVersion>Runservices
  5. In the right panel, locate and delete the entry:
    INFO DATA = %System%\q45de5\apc.exe
  6. In the left panel, double-click the following:
    HKEY_CURRENT_USER>Software>Microsoft>
    Windows>CurrentVersion>Run
  7. In the right panel, locate and delete the entry:
    INFO DATA = %System%\q45de5\apc.exe
  8. In the left panel, double-click the following:
    HKEY_CURRENT_USER>Software>Microsoft>
    Windows>CurrentVersion>Runservices
  9. In the right panel, locate and delete the entry:
    INFO DATA = %System%\q45de5\apc.exe
  10. In the left panel, look for and delete the following keys:
    • HKEY_CURRENT_USER\mIRC
    • HKEY_LOCAL_MACHINE\Software\Classess\.cha
    • HKEY_LOCAL_MACHINE\Software\Classess\.chat
    • HKEY_LOCAL_MACHINE\Software\Classess\irc
    • HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\ CurrentVersion\Uninstall\mirc
    (Note: You may have to reinstall mIRC after completing these instructions, if you are using it.)
  11. Close Registry Editor.

NOTE: If you were not able to terminate the malware process as described in the previous procedure, restart your system.

Additional Windows ME/XP Cleaning Instructions

Users running Windows ME and XP must disable System Restore to allow full scanning of infected systems.

Users running other Windows versions can proceed with the succeeding procedure sets.

Running Trend Micro Antivirus

Scan your system with Trend Micro antivirus and delete all files detected as WORM_RANDON.B. To do this, Trend Micro customers must download the latest pattern file and scan their system. Other Internet users can use HouseCall, Trend Micro�s free online virus scanner.


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