RANSOM_SAMX.A

February 20, 2018
 Analysis by: Marcus Ma. Antonio Capistrano
 ALIASES:

Trojan.Win32.Poweliks.aecv (KASPERSKY), Trojan:Win32/Skeeyah.A!rfn (MICROSOFT), TR/AD.RemoteExecHeur.azmja (ANTIVIR)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware, Downloaded from the Internet

This Ransomware 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:

4,225,536 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

05 Nov 2017

Payload:

Drops files

Arrival Details

This Ransomware 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 Ransomware drops the following files:

  • {malware file path}\data recive
  • {malware file path}\sendBack.txt
  • {malware file path}\secret.txt
  • {malware file path}\secretAES.txt

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • cuteRansomware

Autostart Technique

This Ransomware modifies the following registry entry(ies) to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
adr = {malware file path}

Other Details

This Ransomware does the following:

    • It creates an autostart registry entry using the following commands:
      %System%\rundll32.exe javascript:"\..\mshtml,RunHTMLApplication ";document.write();shell=new%20ActiveXObject("wscript.shell");shell.regwrite("HKEY_CURRENT_USER\\Software\\Microsoft\\Windows\\CurrentVersion\\RunOnce\\adr","{malware path}")
  • Due to some coding errors on the ransomware, it is not able to encrypt files.

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

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.770.04

FIRST VSAPI PATTERN DATE:

09 Nov 2017

VSAPI OPR PATTERN File:

13.771.00

VSAPI OPR PATTERN Date:

10 Nov 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 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\RunOnce
    • adr = {malware file path}

Step 5

Search and delete this file

[ 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.
  • {malware file path}\data recive
  • {malware file path}\sendBack.txt
  • {malware file path}\secret.txt
  • {malware file path}\secretAES.txt

Step 6

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


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