Analysis by: Maureen Reyes
ALIASES:

Ransom:MSIL/Ryzerlo.A (Microsoft), HEUR:Trojan.Win32.Generic (Kaspersky), Ransom.HiddenTear (MalwareBytes)

 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: Downloaded from the Internet, Dropped by other malware

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 encrypts files with specific file extensions. It encrypts files found in specific folders.

  TECHNICAL DETAILS

File Size: 222,720 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 04 Jun 2018
Payload: Drops files, Connects to URLs/IPs, Collects system information, Downloads files, 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:

  • %Desktop%\SUA_CHAVE.html - infection marker

(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.)

It drops the following copies of itself into the affected system:

  • %System Root%\{User Name}\Rand123\local.exe

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

It creates the following folders:

  • %System Root%\{User Name}
  • %System Root%\{User Name}\Rand123

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

Other System Modifications

This Ransomware modifies the following registry entries:

HKEY_CURRENT_USER\Control Panel\Desktop
Wallpaper = "%System Root%\{User Name}\ranso4.jpg"

(Note: The default value data of the said registry entry is {User preference}.)

It sets the system's desktop wallpaper to the following image:

Download Routine

This Ransomware accesses the following websites to download files:

  • http://{BLOCKED}.{BLOCKED}p.blogspot.com/-11m8rWaFmWs/WuhochGTK0I/AAAAAAAAFTY/VkbbVhxYZDgW_jlbQ5lPbV8AEhyd4ihgQCK4BGAYYCw/s1600/ranso4.jpg

It saves the files it downloads using the following names:

  • %System Root%\{User Name}\ranso4.jpg - Ransom Note

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

Information Theft

This Ransomware gathers the following data:

  • Machine Name
  • User Name

Stolen Information

This Ransomware sends the gathered information via HTTP POST to the following URL:

  • http://{BLOCKED}3r2213122c1cxdsxsd.{BLOCKED}x.com/crybrazil/write.php?info={Machine Name}-{User name}_732%20AA151257B1462D642E7E21FF9C80F83CAF043C3572D5ED59BD283D20641E3C9D

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .123
  • .602
  • .3dm
  • .3ds
  • .3g2
  • .3gp
  • .7z
  • .accdb
  • .aes
  • .ai
  • .aif
  • .apk
  • .app
  • .asc
  • .asf
  • .asm
  • .asp
  • .aspx
  • .avi
  • .backup
  • .bak
  • .bat
  • .bmp
  • .brd
  • .bz2
  • .c
  • .cbr
  • .cer
  • .cfg
  • .cfm
  • .cgi
  • .cgm
  • .class
  • .cmd
  • .com
  • .cpp
  • .crt
  • .cs
  • .csr
  • .css
  • .csv
  • .dat
  • .db
  • .dbf
  • .dch
  • .dds
  • .deb
  • .dem
  • .der
  • .dif
  • .dip
  • .djvu
  • .doc
  • .docb
  • .docm
  • .docx
  • .dot
  • .dotm
  • .dotx
  • .dwg
  • .edb
  • .eml
  • .eps
  • .fla
  • .flv
  • .fnt
  • .fon
  • .fpx
  • .frm
  • .gam
  • .ged
  • .gif
  • .gpg
  • .gz
  • .h
  • .htm
  • .html
  • .hwp
  • .ibd
  • .ics
  • .iff
  • .indd
  • .iso
  • .j2c
  • .j2k
  • .jar
  • .java
  • .jfif
  • .jif
  • .jp2
  • .jpeg
  • .jpg
  • .jpx
  • .js
  • .json
  • .jsp
  • .key
  • .keychain
  • .lay
  • .lay6
  • .ldf
  • .log
  • .lua
  • .m3u
  • .m4a
  • .m4u
  • .m4v
  • .max
  • .mdb
  • .mdf
  • .mht
  • .mhtml
  • .mid
  • .mkv
  • .mml
  • .mov
  • .mp3
  • .mp4
  • .mpa
  • .mpeg
  • .mpg
  • .msg
  • .msi
  • .myd
  • .myi
  • .nef
  • .nes
  • .obj
  • .odb
  • .odg
  • .odp
  • .ods
  • .odt
  • .old
  • .onetoc2
  • .ost
  • .otf
  • .otg
  • .otp
  • .ots
  • .ott
  • .p12
  • .pages
  • .PAQ
  • .pas
  • .pcd
  • .pct
  • .pdf
  • .pem
  • .pfx
  • .php
  • .pkg
  • .pl
  • .png
  • .pot
  • .potm
  • .potx
  • .ppam
  • .pps
  • .ppsm
  • .ppsx
  • .ppt
  • .pptm
  • .pptx
  • .prf
  • .prn
  • .ps
  • .ps1
  • .psd
  • .pst
  • .py
  • .rar
  • .raw
  • .rb
  • .rm
  • .rom
  • .rpm
  • .rss
  • .rtf
  • .sav
  • .sch
  • .sdf
  • .sh
  • .sldm
  • .sldx
  • .slk
  • .sln
  • .snt
  • .sql
  • .sqlite3
  • .sqlitedb
  • .srt
  • .stc
  • .std
  • .sti
  • .stw
  • .suo
  • .svg
  • .swf
  • .swift
  • .sxc
  • .sxd
  • .sxi
  • .sxm
  • .sxw
  • .tar
  • .tbk
  • .tex
  • .tga
  • .tgz
  • .thm
  • .tif
  • .tiff
  • .tmp
  • .torrent
  • .ttf
  • .txt
  • .uop
  • .uot
  • .vb
  • .vbs
  • .vcd
  • .vcf
  • .vcxproj
  • .vdi
  • .vmdk
  • .vmx
  • .vob
  • .vsd
  • .vsdx
  • .wav
  • .wb2
  • .wk1
  • .wks
  • .wma
  • .wmv
  • .wpd
  • .wps
  • .xhtml
  • .xla
  • .xlam
  • .xlc
  • .xlm
  • .xls
  • .xlsb
  • .xlsm
  • .xlsx
  • .xlt
  • .xltm
  • .xltx
  • .xlw
  • .xml
  • .xps
  • .yuv
  • .zip
  • .zipx

It encrypts files found in the following folders:

  • %Desktop%
  • %User Profile%\My Documents
  • %User Profile%\Downloads
  • %User Profile%\My Pictures
  • %User Profile%\My Music
  • %User Profile%\My Videos

(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.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.294.02
FIRST VSAPI PATTERN DATE: 04 Jun 2018
VSAPI OPR PATTERN File: 14.295.00
VSAPI OPR PATTERN Date: 05 Jun 2018

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

Restore this modified registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Control Panel\Desktop
    • From: Wallpaper = "%System Root%\{User Name}\ranso4.jpg"
      To: Wallpaper = "{User Preference}"

Step 4

Search and delete these folders

[ 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.
  • %System Root%\{User Name}

Step 5

Search and delete this file

[ 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.  
  • %Desktop%\SUA_CHAVE.html

Step 6

Scan your computer with your Trend Micro product to delete files detected as RANSOM_CRYBRZ.THFDAAH. 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 the following Trend Micro Support pages for more information:

Step 7

Restore encrypted files from backup.


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