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TROJ_DELF.DR

October 08, 2012
 Analysis by: Roland Marco Dela Paz
 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

However, as of this writing, the said sites are inaccessible.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

143,872 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

27 Sep 2010

Arrival Details

However, as of this writing, the said sites are inaccessible.

Installation

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

  • %User Temp%\update.exe

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.)

Download Routine

This Trojan accesses the following websites to download files:

  • http://www.{BLOCKED}stymu.cz/msn.php?id=0

It saves the files it downloads using the following names:

  • %System%\jusched.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

Other Details

This Trojan does the following:

  • It creates the following registry entry to automatically execute the downloaded file at every system startup:
    HKEY_LOCAL_MACHINE\SOFTWARE\MICROSOFT\Windows\CURRENTVERSION\Run
    SunJavaUpdate = %System%\jusched.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It deletes itself after execution.

  SOLUTION

Minimum Scan Engine:

8.900

VSAPI OPR PATTERN File:

07.494.10

VSAPI OPR PATTERN Date:

27 Sep 2010

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

Search and delete these files

[ Learn More ]
There may be some component files that are 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.  %System%\jusched.exe

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
    • SunJavaUpdate = %System%\jusched.exe

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_DELF.DR. 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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