RANSOM_NATAS.SM1

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 connects to certain websites to send and receive information. However, as of this writing, the said sites are inaccessible.

It drops files as ransom note.

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:

• %AppData%\{Random Folder Name}\{Random File Name}.exe

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\Run
{Random Value} = %Application Data%\{Random Folder Name}\{Random File Name}

Other Details

This Ransomware connects to the following website to send and receive information:

• http://{BLOCKED}qjbssfh6gu.{BLOCKED}n.pw/g.php

It displays the following message boxes:

It encrypts files with the following extensions:

• .txt
• .doc
• .docx
• .log
• .msg
• .odt
• .pages
• .rtf
• .tex
• .wpd
• .wps
• .csv
• .dat
• .ged
• .key
• .keychain
• .pps
• .ppt
• .pptx
• .sdf
• .tar
• .tax2014
• .tax2015
• .vcf
• .xml
• .aif
• .iff
• .m3u
• .m4a
• .mid
• .mp3
• .mpa
• .wav
• .wma
• .3g2
• .3gp
• .asf
• .avi
• .flv
• .m4v
• .mov
• .mp4
• .mpg
• .rm
• .srt
• .swf
• .vob
• .wmv
• .3dm
• .3ds
• .max
• .obj
• .lay
• .onetoc2
• .dot
• .bmp
• .dds
• .gif
• .jpg
• .png
• .psd
• .tga
• .thm
• .tif
• .tiff
• .yuv
• .backup
• .ott
• .ai
• .eps
• .ps
• .svg
• .docb
• .indd
• .pct
• .pdf
• .sqlite3
• .sqlitedb
• .xlr
• .xls
• .xlsx
• .pfx
• .accdb
• .db
• .dbf
• .mdb
• .pdb
• .sql
• .dwg
• .dxf
• .asp
• .aspx
• .cer
• .cfm
• .csr
• .css
• .htm
• .html
• .js
• .jsp
• .php
• .rss
• .xhtml
• .mml
• .stc
• .7z
• .cbr
• .deb
• .gz
• .pkg
• .rpm
• .sitx
• .tar.gz
• .zip
• .zipx
• .rar
• .bin
• .cue
• .dmg
• .iso
• .mdf
• .toast
• .vcd
• .c
• .class
• .cpp
• .cs
• .dtd
• .fla
• .h
• .java
• .lua
• .m
• .pl
• .py
• .sh
• .sln
• .swift
• .vb
• .vcxproj
• .xcodeproj
• .bak
• .tmp
• .rar
• .crdownload
• .ics
• .msi
• .part
• .torrent
• .dll
• .sln

It does the following:

• It detects the following debugger process names for its anti debugging routine:
  
  • ProcessHacker.exe
  • tcpview.exe
  • autoruns.exe
  • autorunsc.exe
  • filemon.exe
  • Procmon.exe
  • Procexp.exe
  • idaq.exe
  • idaq64.exe
  • ImmunityDebugger.exe
  • WireShark.exe
  • dumpcap.exe
  • HookExplorer.exe
  • ImportRec.exe
  • PeTools.exe
  • LordPE.exe
  • SysInspector.exe
  • Proc_analyzer.exe
  • sysAnalyzer.exe
  • sniff_hit.exe
  • windbg.exe
  • joeboxcontrol.exe
  • joeboxserver.exe
• Checks for the following USERNAMES to detect if its being debugged:
  
  • SANDBOX
  • VIRUS
  • MALWARE
  • MALTEST
  • TEQUILABOOMBOOM
  • Directory Blacklist
  • SAMPLE
• Detects the presence of WINE:
  
  • wine_get_unix_file_name
• Checks for the following Debugging DLLs:
  
  • Torec.dll
  • Sbiedll.dll
  • Dbghelp.dll
  • Snxhk.dll
  • Api_log.dll
  • Dir_watch.dll
  • Vmcheck.dll
  • Wpespy.dll
  • Pstorec.dll
• Checks if the filename of the malware is:
  
  • Sample.exe
• It detects the presence of the following dll to avoid detection:
  
  • avghooka.dll
  • avghookx.dll

However, as of this writing, the said sites are inaccessible.

Ransomware Routine

This Ransomware avoids encrypting files found in the following folders:

• C:\Windows
• C:\Program Files
• C:\Program Files (x86)

It renames encrypted files using the following names:

• {random characters}.stn

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

• HELP_DECRYPT_FILES.html