Analysis by: JessaD
ALIASES:

W32.Waledac (Symantec), W32/Waledac.gen.e (Mcafee), Mal/WaledPak-A (Sophos)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Propagates via email

This worm propagates by sending messages containing links to sites where it can be downloaded.

It scans the infected system for email addresses and then sends the stolen information to a server via an encrypted file.

It connects to a certain URL to get a list of active peers.

This worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

  TECHNICAL DETAILS

File Size: 411,648 bytes
File Type: PE
Memory Resident: Yes
Initial Samples Received Date: 21 Mar 2009

Arrival Details

This worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

This malware arrives via the following means:

  • Downloaded from links in spam emails.

Autostart Technique

This worm adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
PromoReg = {malware path and filename}.exe

Other System Modifications

This worm adds the following registry entries as part of its installation routine:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
RList = {hex data}

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
MyID = {hex data}

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
FWDone = {hex data}

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
LastCommandId = {hex data}

Other Details

This worm does the following:

  • Propagates by sending email messages containing links to sites where it can be downloaded.
  • Monitors network traffic (HTTP, FTP, etc) to gather credentials.
  • Gathers email adresses from the infected system by scanning all files in pysical and removable drives except those with the following extensions:
    • .avi
    • .bmp
    • .class
    • .dll
    • .exe
    • .gif
    • .hxd
    • .hxh
    • .hxn
    • .hxw
    • .jar
    • .jpeg
    • .jpg
    • .mov
    • .msi
    • .ocx
    • .ogg
    • .rar
    • .vob
    • .wav
    • .wave
    • .wma
    • .wmv
    • .zip
    It then stores them in an encrypted file with .htm or .png as its extension name and sends it to the server.
  • Connects to the following site to get a list of active peers.
    • http://{BLOCKED}rldnews.com/index.php

  SOLUTION

Minimum Scan Engine: 8.900

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Identify and terminate files detected as WORM_WALEDAC.MG

[ Learn More ]
  1. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  2. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 3

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

 
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
    • PromoReg = {malware path and filename}.exe
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
    • RList = {hex data}
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
    • MyID = {hex data}
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
    • FWDone = {hex data}
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
    • LastCommandId = {hex data}

Step 4

Scan your computer with your Trend Micro product to delete files detected as WORM_WALEDAC.MG. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.


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