BKDR_POISON.Y

 Analysis by: Pearl Charlaine Espejo

 ALIASES:

TR/AD.Poison.mugno (Avira); Backdoor.Poison.6942 (CAT-QuickHeal); Backdoor:Win32/Poison.P (Microsoft)

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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.

  TECHNICAL DETAILS

File Size:

57,344 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

03 Feb 2017

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.

Other System Modifications

This backdoor adds the following registry keys:

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\
bakshell

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\
bakshell\Recent File List

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\
bakshell\Settings

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Bakshell.Document

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Bakshell.Document\DefaultIcon

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Bakshell.Document\shell\open\
command

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Bakshell.Document\shell\print\
command

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Bakshell.Document\shell\printto\
command

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.sefut

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.sefut\ShellNew

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Bakshell.Document

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Bakshell.Document\DefaultIcon

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Bakshell.Document\shell\open\
command

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Bakshell.Document\shell\print\
command

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Bakshell.Document\shell\printto\
command

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.sefut

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.sefut\ShellNew
NullFile = ""

Other Details

This backdoor connects to the following possibly malicious URL:

  • gold.{BLOCKED}rple.com

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.212.03

FIRST VSAPI PATTERN DATE:

10 Feb 2017

VSAPI OPR PATTERN File:

13.213.00

VSAPI OPR PATTERN Date:

11 Feb 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

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 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_CURRENT_USER\Software\Local AppWizard-Generated Applications
    • bakshell
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes
    • Bakshell.Document

Step 5

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\Classes\.sefut
    • = "Bakshell.Document"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.sefut\ShellNew
    • NullFile = ""

Step 6

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