WORM_RANDEX.MS

Malware type: Worm

In the wild: No

Destructive: No

Language: English

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

Encrypted: No

Overall risk rating:

Reported infections:

Damage potential:

High

Distribution potential:

High

Description: 

This memory-resident worm drops itself as the file MICROSOFT.EXE in the system folder. It spreads via network shares and acts as an Internet Relay Chat (IRC) bot.

It logs on to a server and allows a malicious user to perform the following tasks on a target system:

  • Update the malware copy
  • List and terminate running processes
  • Download and execute files
  • Send system information such as:
    • Version
    • CPU speed
    • Total and free memory
    • Operating System
    • System time and date
    • IP
    • Host name
    • Windows and Windows system folders

It runs on Windows 98, ME, NT, 2000, and XP.

For additional information about this threat, see:

Description created: Jan. 31, 2004 5:54:23 AM GMT -0800
Description updated: Jan. 31, 2004 5:54:21 AM GMT -0800


TECHNICAL DETAILS


Size of malware: 43,008 Bytes

Initial samples received on: Jan 31, 2004

Details:

Installation and Autostart Techniques

Upon execution, this memory-resident worm drops a copy of itself as the file MICROSOFT.EXE in the system folder. Afterward, it executes the said dropped file.

It creates the following registry entries to automatically execute at every system startup:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
Dcom System Patch �Microsoft.exe�

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Runonce
Dcom System Patch �Microsoft.exe�

Network Propagation

This malware spreads via network shares. It drops copies of itself in the following shared folders:

  • Admin$\system32\
  • c$\winnt\system32\
  • ipc$

It enumerates all users in the network by accessing all user accounts in the server. It does this using the API NetUserEnum. After creating the malware copy on an infected machine, this worm executes the file using the API NetScheduleJobAdd.

Backdoor Capabilities

This malware acts like an Internet Relay Chat (IRC) bot. It logs on to a server and waits for several commands from a remote user.

It allows the malicious user to perform the following malicious actions on the infected system:

  • Update the malware copy
  • List and terminate running processes
  • Download and execute files
  • Send system information such as:
    • Version
    • CPU speed
    • Total and free memory
    • Operating System
    • System time and date
    • IP
    • Host name
    • Windows and Windows system folders



Analysis by: Arman Catacutan


SOLUTION


Minimum scan engine version needed: 6.500

Pattern file needed: 1.752.29

Pattern release date: Jan 31, 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 from memory.

  1. Open Windows Task Manager.
    On Windows 95/98/ME systems, press
    CTRL%20ALT%20DELETE
    On Windows NT/2000/XP systems, press
    CTRL%20SHIFT%20ESC, and click the Processes tab.
  2. In the list of running programs*, locate the process:
    MICROSOFT.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/ME, Windows Task Manager may not show certain processes. You may use a third party process viewer 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 during startup.

  1. Open Registry Editor. To do this, 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:
    Dcom System Patch �Microsoft.exe�
  4. In the left panel, double-click the following:
    HKEY_CURRENT_USER>Software>Microsoft>
    Windows>CurrentVersion>Runonce
  5. In the right panel, locate and delete the entry:
    Dcom System Patch �Microsoft.exe�
  6. Close Registry Editor.
NOTE: If you were not able to terminate the malware process from memory as described in the previous procedure, restart your system.

Additional Windows ME/XP Cleaning Instructions

Running Trend Micro Antivirus

Scan your system with Trend Micro antivirus and delete all files detected as WORM_RANDEX.MS. 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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