TROJ_LETHIC.WSVQ

March 17, 2017
 Analysis by: Cris Nowell Pantanilla
 ALIASES:

Trojan.Win32.Scar.prlk (Kaspersky)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 REPORTED INFECTION:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

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:

320,512 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

16 Mar 2017

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 copies of itself into the affected system and executes them:

  • %AppData%\roaming\{GUID}\{random}.exe

It adds the following processes:

  • svchost.exe

It creates the following folders:

  • %AppData%\roaming\{GUID}

It injects codes into the following process(es):

  • svchost.exe

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
{GUID} = "%AppData%\roaming\{GUID}\{random}.exe"

Other Details

This Trojan does the following:

  • It checks for the following strings to avoid virtual machines:
    • vbox
    • qemu
    • vmware
    • virtual hd

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.280.07

FIRST VSAPI PATTERN DATE:

16 Mar 2017

VSAPI OPR PATTERN File:

13.281.00

VSAPI OPR PATTERN Date:

17 Mar 2017

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

Restart in Safe Mode

[ Learn More ]

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
    • {GUID} = "%AppData%\roaming\{GUID}\{random}.exe"

Step 4

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.  %AppData%\roaming\{GUID}

Step 5

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