RANSOM_SAPNUPUAS.A

September 29, 2017
 Analysis by: Johnlery Triunfante
 ALIASES:

Trojan:Win32/Vagger!rfn (MICROSOFT); Trojan.Ransom.BUF (BITDEFENDER); MSIL/LockScreen.WH!tr (FORTINET)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: Yes

  • 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:

1,258,496 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

21 Sep 2017

Payload:

Displays graphics/image

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 adds the following folders:

  • %User Temp%\{random hex value}.tmp
  • %User Temp%\{random hex value}.tmp\Tools

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.)

It drops the following files:

  • %User Temp%\{random hex value}.tmp\{random hex value}.bat → starts nRansom.exe
  • %User Temp%\{random hex value}.tmp\nRansom.exe → Detected as Ransom_Agent.R050C0OIO17
  • %User Temp%\{random hex value}.tmp\Interop.WMPLib.dll
  • %User Temp%\{random hex value}.tmp\AxInterop.WMPLib.dll
  • %User Temp%\{random hex value}.tmp\Tools\your-mom-gay.mp3 → plays in the background

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.)

Other Details

This Ransomware does the following:

  • Executes the following command:
    • "%System%\cmd.exe" /c "%User Temp%\{random hex value}.tmp\{random hex value}.bat {malware path}\{malware name}.exe"
  • Executes the following command when pressing unlock button:
    • cmd.exe /c del %User Startup%\nLocker.exe
  • This ransomware does not encrypt files.

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.. %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

NOTES:

This ransomware displays the following lockscreen as ransom note. Unlock code is 12345

It also displays the following window after unlocking the ransom note:

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.674.08

FIRST VSAPI PATTERN DATE:

22 Sep 2017

VSAPI OPR PATTERN File:

13.675.00

VSAPI OPR PATTERN Date:

23 Sep 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

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.  
  • %User Temp%\{random hex value}.tmp

Step 5

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