Analysis by: Marcus Ma. Antonio Capistrano
ALIASES:

Trojan.FakeAV (NORTON), Trojan:Win32/Tiggre!rfn (MICROSOFT),

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • 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: 20,992 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 12 Jan 2018
Payload: Drops 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.

Other Details

This Trojan does the following:

  • Once executed, this Trojan will display a transparent window prompting the user of the file encryption. It does not encrypt files but once the window is closed, it attempts to delete all registry keys from the machine using the commands:
    • cmd.exe /C reg delete HKEY_CURRENT_CONFIG
    • cmd.exe /C reg delete HKEY_CLASSES_ROOT
    • cmd.exe /C reg delete HKEY_USERS
    • cmd.exe /C reg delete HKEY_CURRENT_USER
    • cmd.exe /C reg delete HKEY_LOCAL_MACHINE

NOTES:

The encryption/infection note shown as a transparent window.

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.912.04
FIRST VSAPI PATTERN DATE: 18 Jan 2018
VSAPI OPR PATTERN File: 13.913.00
VSAPI OPR PATTERN Date: 19 Jan 2018

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_FAKEKILLBOT.THAORAH

[ 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

Restore these deleted registry keys/values from backup

*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

 
  • HKEY_CURRENT_CONFIG
  • HKEY_CLASSES_ROOT
  • HKEY_USERS
  • HKEY_CURRENT_USER
  • HKEY_LOCAL_MACHINE

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_FAKEKILLBOT.THAORAH. 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 the following Trend Micro Support pages for more information:


Did this description help? Tell us how we did.