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WORM_DOWNAD.EJ

December 05, 2012
 Analysis by: Mark Joseph Manahan
 ALIASES:

Worm:Win32/Conficker.B (Microsoft), W32/Conficker.worm.gen.a (McAfee), W32.Downadup.B (Symantec)

 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

This worm arrives by connecting affected removable drives to a system. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It drops copies of itself into network drives. It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

  TECHNICAL DETAILS

File Size:

158,003 bytes

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

19 Sep 2012

Arrival Details

This worm arrives by connecting affected removable drives to a system.

It may arrive via network shares.

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

Installation

This worm drops the following copies of itself into the affected system:

  • %System%\{random number}.tmp
  • %Program Files%\Internet Explorer\{random file name}.dll
  • %Program Files%\Movie Maker\{random file name}.dll

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

Autostart Technique

This worm is a .DLL file that adds the following services:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random service name}
ImagePath = "%System%\{random number}.tmp"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random service name}

Propagation

This worm creates the following folders in all removable drives:

  • Recycler\{SID}

It drops the following copy(ies) of itself in all removable drives:

  • Recycler\{SID}\{random characters}.{random}

It drops copies of itself into network drives.

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

Other Details

This worm connects to the following URL(s) to get the affected system's IP address:

  • http://www.whatsmyipaddress.com
  • http://www.whatismyip.org
  • http://www.getmyip.org
  • http://checkip.dyndns.org

It connects to the following possibly malicious URL:

  • http://{pseudorandom}.biz/search?q={value}
  • http://{pseudorandom}.cc/search?q={value}
  • http://{pseudorandom}.org/search?q={value}
  • http://{pseudorandom}.net/search?q={value}
  • http://{pseudorandom}.com/search?q={value}
  • http://{pseudorandom}.ws/search?q={value}
  • http://{pseudorandom}.cn/search?q={value}
  • http://{pseudorandom}.info/search?q={value}

It connects to the following time servers to determine the current date:

  • myspace.com
  • msn.com
  • ebay.com
  • cnn.com
  • aol.com
  • w3.org
  • ask.com
  • yahoo.com
  • google.com
  • baidu.com

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

9.406.01

FIRST VSAPI PATTERN DATE:

19 Sep 2012

VSAPI OPR PATTERN File:

9.407.00

VSAPI OPR PATTERN Date:

19 Sep 2012

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

Restart in Safe Mode

[ Learn More ]

Step 3

To delete the random service key this malware/grayware created:

  1. Scan your computer with your Trend Micro product and take note of the name of the malware/grayware/spyware detected.
  2. Open Registry Editor. To do this, click Start>Run, type regedit in the text box provided, then press Enter.
  3. Press CTRL+F.
  4. In the Find dialog box, type the file name of the malware detected earlier.
    (Note: Make sure that only the data checkbox is selected, then click Find Next.)

    5. Find.

  5. Once found, in the right panel, check if the result is the following value-data pair:
    ImagePath = {malware/grayware path and file name}
  6. If yes, in the left panel, locate the service where the data is under.
  7. Right-click on the located service in the left panel and choose Delete.
  8. Repeat steps 2 to 6 until the Finished searching through the registry dialog box appears.
  9. Close Registry Editor.

Step 4

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • {drive letter}:\Recycler\{SID}

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_DOWNAD.EJ. 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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