TROJ_MISLEADAPP.E

 Analysis by: Sabrina Lei Sioting

 ALIASES:

Adware:Win32/Kwsearchguide (Microsoft), Adware.KMGuide (Symantec), Kwsearchguide (Sunbelt), Adware/KSG (Fortinet),

 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:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

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

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

  TECHNICAL DETAILS

File Size:

409,600 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

01 Jan 2013

Payload:

Drops files, Downloads files

Arrival Details

This Trojan 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 Trojan drops the following files:

  • %Windows%\ab7498d3.lg
  • %Windows%\trkwksa.dll
  • %Windows%\trkwksa.exe

(Note: %Windows% is the Windows folder, which is usually C:\Windows.)

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
trkwksa = "%Windows%\trkwksa.exe"

Other System Modifications

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

HKEY_CURRENT_USER\Software\hycg\
hycg
lld = "{month-day of execution}"

HKEY_CURRENT_USER\Software\hycg\
hycg
pddc = "{month-day of execution}"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
kwsg
DisplayName = "Addendum Sidebar"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
kwsg
UninstallString = ""%Windows%\trkwksa.exe" /dels"

It adds the following registry keys as part of its installation routine:

HKEY_CURRENT_USER\Software\hycg

HKEY_CURRENT_USER\Software\hycg\
hycg

HKEY_CURRENT_USER\Software\Microsoft\
ab7498d3

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
kwsg

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}.kwsearchguide.com/rep/lect.php
  • http://{BLOCKED}.kwsearchguide.com/sb_conf.php?ovt=
  • http://{BLOCKED}.kwsearchguide.com/xmlup/urls.php?ovt=
  • http://{BLOCKED}ymatch.kr/old/pogej.dll
  • http://{BLOCKED}ymatch.kr/old/pogej.exe
  • http://{BLOCKED}earchguide.com/log-bin/alive.php?ovt=
  • http://{BLOCKED}earchguide.com/log-bin/statics.php?maddr={mac address}&ipaddr={ip address}&ovt=&action=update
  • http://{BLOCKED}earchguide.com/log-bin/statics.php?maddr={mac address}&ipaddr={ip address}&ovt=&verno=&action=load

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

  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

Identify and terminate files detected as TROJ_MISLEADAPP.E

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. 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.
  3. 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 key

[ 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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.

  • In HKEY_CURRENT_USER\Software
    • hycg
  • In HKEY_CURRENT_USER\Software\Microsoft
    • ab7498d3
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall
    • kwsg

Step 4

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
    • trkwksa = "%Windows%\trkwksa.exe"

Step 5

Search and delete this file

[ Learn More ]
There may be some 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.  %Windows%\ab7498d3.lg
%Windows%\trkwksa.dll
%Windows%\trkwksa.exe

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_MISLEADAPP.E. 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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