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BKDR_SETHC.D

August 21, 2018
 Analysis by: Noel Anthony Llimos
 ALIASES:

Backdoor:Win32/Shiftdoor (Microsoft)

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

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

It executes commands from a remote malicious user, effectively compromising the affected system.

It requires being executed with a specific argument/parameter, an additional component, or in a specific environment in order to proceed with its intended routine.

  TECHNICAL DETAILS

File Size:

644,816 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

20 Aug 2018

Payload:

Drops files

Arrival Details

This Backdoor 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 Backdoor drops the following non-malicious file:

  • %Fonts%\rundl132.exe ← Copy of the original sethc.exe

(Note: %Fonts% is the Windows Fonts folder, which is usually C:\Window\Fonts on Windows 2000, XP, Server 2003, Vista, 7, and 8.)

Backdoor Routine

This Backdoor executes the following commands from a remote malicious user:

  • Execute Files
  • Terminate Itself
  • Delete Itself
  • Execute cmd.exe
  • Modify Files

Other Details

This Backdoor does the following:

  • If the user will press the SHIFT key 5 times when the user is logged in, the normal sticky keys window will pop up. While if the user is in the Windows Login Screen, a window will pop up where it can execute specific commands and arguments.
  • It replaces the file %System%\sethc.exe to itself

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It requires being executed with a specific argument/parameter, an additional component, or in a specific environment in order to proceed with its intended routine.

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.454.05

FIRST VSAPI PATTERN DATE:

20 Aug 2018

VSAPI OPR PATTERN File:

14.455.00

VSAPI OPR PATTERN Date:

21 Aug 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

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

Identify and terminate files detected as BKDR_SETHC.D

[ 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 4

Search and delete these files

[ 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.  
  • %System%\sethc.exe

Step 5

Scan your computer with your Trend Micro product to delete files detected as BKDR_SETHC.D. 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:


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