RANSOM_SAMAS.N

August 10, 2017
 Analysis by: Johnlery Triunfante
 ALIASES:

Mal/Samas-C (SOPHOS_LITE); Ransom:MSIL/Samas!rfn (MICROSOFT)

 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.

It deletes itself after execution.

It encrypts files with specific file extensions. It drops files as ransom note.

  TECHNICAL DETAILS

File Size:

127,488 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

30 Jul 2017

Payload:

Displays windows, Encrypts 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:

  • %ProgramData%\greenwin\startinfo.bat

(Note: %ProgramData% is the Program Data folder, where it usually is C:\Program Files in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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.)

It creates the following folders:

  • %ProgramData%\greenwin

(Note: %ProgramData% is the Program Data folder, where it usually is C:\Program Files in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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.)

Other Details

This Ransomware does the following:

  • Avoids encrypting files with the following extensions:
    • .exe
    • .msi
    • .lnk
    • .wim
    • .scf
    • .ini
    • .sys
    • .dll
    • .supported2017
  • Executes the following command:
    • cmd /c "%ProgramData%\greenwin\startinfo.bat
    • ping 127.0.0.1 -n 5

(Note: %ProgramData% is the Program Data folder, where it usually is C:\Program Files in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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.)

It deletes itself after execution.

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .vb
  • .asmx
  • .config
  • .3dm
  • .3ds
  • .3fr
  • .3g2
  • .3gp
  • .3pr
  • .7z
  • .ab4
  • .accdb
  • .accde
  • .accdr
  • .accdt
  • .ach
  • .acr
  • .act
  • .adb
  • .ads
  • .agdl
  • .ai
  • .ait
  • .al
  • .apj
  • .arw
  • .asf
  • .asm
  • .asp
  • .aspx
  • .asx
  • .avi
  • .awg
  • .back
  • .backup
  • .backupdb
  • .bak
  • .lua
  • .m
  • .m4v
  • .max
  • .mdb
  • .mdc
  • .mdf
  • .mef
  • .mfw
  • .mmw
  • .moneywell
  • .mos
  • .mov
  • .mp3
  • .mp4
  • .mpg
  • .mrw
  • .msg
  • .myd
  • .nd
  • .ndd
  • .nef
  • .nk2
  • .nop
  • .nrw
  • .ns2
  • .ns3
  • .ns4
  • .nsd
  • .nsf
  • .nsg
  • .nsh
  • .nwb
  • .nx2
  • .nxl
  • .nyf
  • .tif
  • .tlg
  • .txt
  • .vob
  • .wallet
  • .war
  • .wav
  • .wb2
  • .wmv
  • .wpd
  • .wps
  • .x11
  • .x3f
  • .xis
  • .xla
  • .xlam
  • .xlk
  • .xlm
  • .xlr
  • .xls
  • .xlsb
  • .xlsm
  • .xlsx
  • .xlt
  • .xltm
  • .xltx
  • .xlw
  • .xml
  • .ycbcra
  • .yuv
  • .zip
  • .sqlite
  • .sqlite3
  • .sqlitedb
  • .sr2
  • .srf
  • .srt
  • .srw
  • .st4
  • .st5
  • .st6
  • .st7
  • .st8
  • .std
  • .sti
  • .stw
  • .stx
  • .svg
  • .swf
  • .sxc
  • .sxd
  • .sxg
  • .sxi
  • .sxm
  • .sxw
  • .tex
  • .tga
  • .thm
  • .tib
  • .py
  • .qba
  • .qbb
  • .qbm
  • .qbr
  • .qbw
  • .qbx
  • .qby
  • .r3d
  • .raf
  • .rar
  • .rat
  • .raw
  • .rdb
  • .rm
  • .rtf
  • .rw2
  • .rwl
  • .rwz
  • .s3db
  • .sas7bdat
  • .say
  • .sd0
  • .sda
  • .sdf
  • .sldm
  • .sldx
  • .sql
  • .pdd
  • .pdf
  • .pef
  • .pem
  • .pfx
  • .php
  • .php5
  • .phtml
  • .pl
  • .plc
  • .png
  • .pot
  • .potm
  • .potx
  • .ppam
  • .pps
  • .ppsm
  • .ppsx
  • .ppt
  • .pptm
  • .pptx
  • .prf
  • .ps
  • .psafe3
  • .psd
  • .pspimage
  • .pst
  • .ptx
  • .oab
  • .obj
  • .odb
  • .odc
  • .odf
  • .odg
  • .odm
  • .odp
  • .ods
  • .odt
  • .oil
  • .orf
  • .ost
  • .otg
  • .oth
  • .otp
  • .ots
  • .ott
  • .p12
  • .p7b
  • .p7c
  • .pab
  • .pages
  • .pas
  • .pat
  • .pbl
  • .pcd
  • .pct
  • .pdb
  • .gray
  • .grey
  • .gry
  • .h
  • .hbk
  • .hpp
  • .htm
  • .html
  • .ibank
  • .ibd
  • .ibz
  • .idx
  • .iif
  • .iiq
  • .incpas
  • .indd
  • .jar
  • .java
  • .jpe
  • .jpeg
  • .jpg
  • .jsp
  • .kbx
  • .kc2
  • .kdbx
  • .kdc
  • .key
  • .kpdx
  • .doc
  • .docm
  • .docx
  • .dot
  • .dotm
  • .dotx
  • .drf
  • .drw
  • .dtd
  • .dwg
  • .dxb
  • .dxf
  • .dxg
  • .eml
  • .eps
  • .erbsql
  • .erf
  • .exf
  • .fdb
  • .ffd
  • .fff
  • .fh
  • .fhd
  • .fla
  • .flac
  • .flv
  • .fmb
  • .fpx
  • .fxg
  • .cpp
  • .cr2
  • .craw
  • .crt
  • .crw
  • .cs
  • .csh
  • .csl
  • .csv
  • .dac
  • .bank
  • .bay
  • .bdb
  • .bgt
  • .bik
  • .bkf
  • .bkp
  • .blend
  • .bpw
  • .c
  • .cdf
  • .cdr
  • .cdr3
  • .cdr4
  • .cdr5
  • .cdr6
  • .cdrw
  • .cdx
  • .ce1
  • .ce2
  • .cer
  • .cfp
  • .cgm
  • .cib
  • .class
  • .cls
  • .cmt
  • .cpi
  • .ddoc
  • .ddrw
  • .dds
  • .der
  • .des
  • .design
  • .dgc
  • .djvu
  • .dng
  • .db
  • .db-journal
  • .db3
  • .dcr
  • .dcs
  • .ddd
  • .dbf
  • .dbx
  • .dc2
  • .pbl

It avoids encrypting files with the following strings in their file name:

  • desktop.ini
  • startinfo.bat
  • READ-FOR-DECCCC-FILESSS.html
  • ntuser.dat
  • search-ms

It avoids encrypting files with the following strings in their file path:

  • reference assemblies\microsoft
  • microsoft\windows
  • appdata
  • recycle.bin

It avoids encrypting files found in the following folders:

  • %System Root%\windows
  • %System Root%\winnt
  • %System Root%\users\all users
  • %System Root%\boot
  • %System Root%\users\default

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

It appends the following extension to the file name of the encrypted files:

  • .supported2017

It drops the following file(s) as ransom note:

  • Drops the following files to the desktop of all users:
    • READ-FOR-DECCCC-FILESSS_0.html
    • READ-FOR-DECCCC-FILESSS_1.html
    • READ-FOR-DECCCC-FILESSS_2.html
    • READ-FOR-DECCCC-FILESSS_3.html
    • READ-FOR-DECCCC-FILESSS_4.html
    • READ-FOR-DECCCC-FILESSS_5.html
    • READ-FOR-DECCCC-FILESSS_6.html
    • READ-FOR-DECCCC-FILESSS_7.html
    • READ-FOR-DECCCC-FILESSS_8.html
    • READ-FOR-DECCCC-FILESSS_9.html
  • {directory of encrypted file}\READ-FOR-DECCCC-FILESSS.html
  • {directory of encrypted file}\000-READ-FOR-DECCCC-FILESSS.html
  • {directory of encrypted file}\001-READ-FOR-DECCCC-FILESSS.html
  • {directory of encrypted file}\002-READ-FOR-DECCCC-FILESSS.html
  • {directory of encrypted file}\003-READ-FOR-DECCCC-FILESSS.html
  • {directory of encrypted file}\004-READ-FOR-DECCCC-FILESSS.html
  • {directory of encrypted file}\005-READ-FOR-DECCCC-FILESSS.html
  • {directory of encrypted file}\006-READ-FOR-DECCCC-FILESSS.html
  • {directory of encrypted file}\007-READ-FOR-DECCCC-FILESSS.html
  • {directory of encrypted file}\008-READ-FOR-DECCCC-FILESSS.html
  • {directory of encrypted file}\009-READ-FOR-DECCCC-FILESSS.html

NOTES:

This ransomware displays the following ransom note:

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.568.05

FIRST VSAPI PATTERN DATE:

01 Aug 2017

VSAPI OPR PATTERN File:

13.569.00

VSAPI OPR PATTERN Date:

02 Aug 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

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.  
  • %ProgramData%\greenwin

Step 4

Search and delete these files

[ 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.
  • READ-FOR-DECCCC-FILESSS_0.html
  • READ-FOR-DECCCC-FILESSS_1.html
  • READ-FOR-DECCCC-FILESSS_2.html
  • READ-FOR-DECCCC-FILESSS_3.html
  • READ-FOR-DECCCC-FILESSS_4.html
  • READ-FOR-DECCCC-FILESSS_5.html
  • READ-FOR-DECCCC-FILESSS_6.html
  • READ-FOR-DECCCC-FILESSS_7.html
  • READ-FOR-DECCCC-FILESSS_8.html
  • READ-FOR-DECCCC-FILESSS_9.html
  • {directory of encrypted file}\READ-FOR-DECCCC-FILESSS.html
  • {directory of encrypted file}\000-READ-FOR-DECCCC-FILESSS.html
  • {directory of encrypted file}\001-READ-FOR-DECCCC-FILESSS.html
  • {directory of encrypted file}\002-READ-FOR-DECCCC-FILESSS.html
  • {directory of encrypted file}\003-READ-FOR-DECCCC-FILESSS.html
  • {directory of encrypted file}\004-READ-FOR-DECCCC-FILESSS.html
  • {directory of encrypted file}\005-READ-FOR-DECCCC-FILESSS.html
  • {directory of encrypted file}\006-READ-FOR-DECCCC-FILESSS.html
  • {directory of encrypted file}\007-READ-FOR-DECCCC-FILESSS.html
  • {directory of encrypted file}\008-READ-FOR-DECCCC-FILESSS.html
  • {directory of encrypted file}\009-READ-FOR-DECCCC-FILESSS.html

Step 5

Scan your computer with your Trend Micro product to clean files detected as RANSOM_SAMAS.N. 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.

Step 6

Restore encrypted files from backup.


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