Analysis by: Janus Agcaoili
 PLATFORM:

Windows

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

  • Threat Type: File infector

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Dropped by other malware, Downloaded from the Internet

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

It does not have any propagation routine.

It does not have any backdoor routine.

  TECHNICAL DETAILS

File Size: Varies
File Type: EXE, Other
Memory Resident: No
Initial Samples Received Date: 24 Oct 2016
Payload: Infects files

Arrival Details

This file infector 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 file infector drops and executes the following files:

  • %Application Data%\services.exe <- with argument "-?cwk", Detected as PE_KOLOBOK.A-O
  • {Current Path}\{Current Name}.{random 3 letters} <- Original host file, deleted after execution

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

File Infection

This is the Trend Micro detection for files infected by:

  • PE_KOLOBOK.A-O

Propagation

This file infector does not have any propagation routine.

Backdoor Routine

This file infector does not have any backdoor routine.

Other Details

This file infector does the following:

  • Executes the original host file to trick the users to think that they were running a normal file
  • Uses the File Icon and File Details of the infected host for its dropped mother file

NOTES:

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.856.05
FIRST VSAPI PATTERN DATE: 24 Oct 2016
VSAPI OPR PATTERN File: 12.857.00
VSAPI OPR PATTERN Date: 25 Oct 2016

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

Remove the malware/grayware file dropped/downloaded by PE_KOLOBOK.A. (Note: Please skip this step if the threat(s) listed below have already been removed.)

     PE_KOLOBOK.A-O

Step 5

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

Step 6

Scan your computer with your Trend Micro product to delete files detected as PE_KOLOBOK.A. 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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