Analysis by: Vincent Martin Hermosura

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: 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.

  TECHNICAL DETAILS

File Size: 1,462,037 bytes
File Type: DLL
Memory Resident: Yes
Initial Samples Received Date: 18 Aug 2014
Payload: Modifies system registry

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 adds the following processes:

  • svchost.exe

It injects codes into the following process(es):

  • svchost.exe

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_WCESVC

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_WCESVC\
0000

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_WCESVC\
0000\Control

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Wcesvc\Parameters

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Jet\4.0\Engines
SandBoxMode = "dword:00000002"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SvcHost
Wcesvc = "Wcesvc"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_WCESVC\
0000
Service = "Wcesvc"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_WCESVC\
0000\Control
ActiveService = "Wcesvc"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Wcesvc
ImagePath = "%System%\svchost.exe -k "Wcesvc""

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Wcesvc\Parameters
ServiceDll = "{malware path and file name}"

  SOLUTION

Minimum Scan Engine: 9.700

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Restart in Safe Mode

[ Learn More ]

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Jet\4.0\Engines
    • SandBoxMode = "dword:00000002"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SvcHost
    • Wcesvc = "Wcesvc"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_WCESVC\0000
    • Service = "Wcesvc"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_WCESVC\0000\Control
    • ActiveService = "Wcesvc"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Wcesvc
    • ImagePath = "%System%\svchost.exe -k "Wcesvc""
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Wcesvc\Parameters
    • ServiceDll = "{malware path and file name}"

Step 5

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.

  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\Root
    • LEGACY_WCESVC
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_WCESVC
    • 0000
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_WCESVC\0000
    • Control
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Wcesvc
    • Parameters

Step 6

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