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TROJ_DLOADER.APP

July 24, 2013
 ALIASES:

Downloader-AEU (McAfee); Downloader (Symantec); TR/Dldr.Small.FJ.1 (Avira)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes


  TECHNICAL DETAILS

File Size:

38,400 bytes

Memory Resident:

Yes

Initial Samples Received Date:

01 Jul 2007

Autostart Technique

This Trojan registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Dongtian\
Service
DTInstall = "{malware path and file name}"

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
DTService = "rundll32.exe {malware path and file name},Load"

NOTES:

This Trojan may be used by other malware in performing their malicious routines.

It requires other components in order to run properly.

  SOLUTION

Minimum Scan Engine:

9.300

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Scan your computer with your Trend Micro product and note files detected as TROJ_DLOADER.APP

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Delete this registry key

[ Learn More ]

=Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator’s help. You may also check out this Microsoft article first before modifying your computer's registry.

  • HKEY_LOCAL_MACHINE\SOFTWARE\Dongtian
    • Service

Step 5

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\policies\Explorer\Run
    • DTService = rundll32.exe {malware path and file name},Load

Step 6

Search and delete the files detected as TROJ_DLOADER.APP

*Note: Some component files may be hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files and folders in the search result.

To stop the malware/grayware from running when certain files are opened:

For Windows 2000, Windows XP, and Windows Server 2003:

  1. Right-click Start then click Search....
  2. In the Named input box, type the name of the file that was detected earlier.
  3. In the Look In drop-down list, select My Computer then press Enter.
  4. Once located, select the file then press SHIFT+DELETE to delete it.

For Windows Vista and Windows 7:

  1. Click Start>Computer.
  2. In the Search Computer input box, type the name of the file detected earlier, and press Enter.
  3. Once located, select the file then press SHIFT+DELETE to delete it.
    *Note: Read the following Microsoft page if these steps do not work on Windows 7.

Step 7

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