Analysis by: Johnlery Triunfante
ALIASES:

HEUR:Trojan.Win32.Generic (Kaspersky); Ransom:Win32/Ergop.A (Microsoft); Generic.Ransom.GlobeImposter.3EF7021C (Bitdefender)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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.

It is capable of encrypting files in the affected system.

  TECHNICAL DETAILS

File Size: 56,320 bytes
File Type: EXE
Initial Samples Received Date: 07 Dec 2017

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 copies of itself into the affected system:

  • %Application Data%\{malware name}.exe

(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.)

It drops the following files:

  • {encrypted files path}\how_to_back_files.html
  • %System Root%\Users\Public\{random hex string}
  • %User Temp%\tmp{random string}.tmp.bat

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

Autostart Technique

This Ransomware adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
BrowserUpdateCheck = %Application Data%\{malware name}.exe

Other System Modifications

This Ransomware adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Terminal Server Client\Servers
(Default) = ""

It deletes the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Terminal Server Client\Default

HKEY_CURRENT_USER\Software\Microsoft\
Terminal Server Client\Servers

Other Details

This Ransomware is capable of encrypting files in the affected system.