Analysis by: adel

 PLATFORM:

Windows 98, ME, NT, 2000, XP, Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This {malware/spyware type} has received attention from independent media sources and/or other security firms.

To get a one-glance comprehensive view of the behavior of this Trojan, refer to the Threat Diagram shown below.

This Trojan may be downloaded by other malware/grayware from remote sites. However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

Arrival Details

This Trojan may be downloaded by the following malware/grayware from remote sites:

  • JS_SHELLCOD.JDT

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%\mshmail.exe
  • %User Temp%\svchost.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.)

It drops the following files:

  • %User Temp%\wshiph.dll

(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.)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
mshmail = %User Temp%\mshmail.exe -installkys

Download Routine

This Trojan accesses the following websites to download files:

  • https://www.{BLOCKED}kor.com/asp/kys_allow_get.asp?name=getkys.dat

Other Details

Based on analysis of the codes, it has the following capabilities:

  • This file may be executed using the following switches:
    • removekys
    • installkys
  • It copies the creation date and time of the legitimate svchost.exe and uses it to set the following file's creation time:
    • %User Temp%\svchost.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.)

  SOLUTION

VSAPI OPR PATTERN File: 6.913.00
VSAPI OPR PATTERN Date: 11 Mar 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

Remove malware files dropped/downloaded by TROJ_INJECT.JDT

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • mshmail = %User Temp%\mshmail.exe -installkys

Step 4

Search and delete this file

[ 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.
  • %UserTemp%\mshmail.exe
  • %UserTemp%\svchost.exe
  • %UserTemp%\wshiph.dll

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_INJECT.JDT. 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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