RANSOM_SAMAS.E
Ransom:MSIL/Samas.A (Microsoft); Trojan-Ransom.MSIL.Samas.as (Kaspersky); Ransom.FileCryptor (Malwarebytes); a variant of MSIL/Filecoder.Samas.B (ESET-NOD32); Win32:Ransom-AYO [Trj] (Avast)
Windows

Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This Trojan 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
53,248 bytes
EXE
10 Jan 2017
Arrival Details
This Trojan 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 Trojan drops and executes the following files:
- %All Users Profile%\Application Data\Msdtc\mustupdate.bat
(Note: %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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 Trojan renames encrypted files using the following names:
- {Original Filename and Extension}.deria.wowreadfordecryp
It drops the following file(s)/component(s):
- %Desktop%\{numbers}-WOW-READ-FOR-DECRYP.html
(Note: %Desktop% is the desktop folder, where it usually is C:\Documents and Settings\{user name}\Desktop in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\Desktop in 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.)