RANSOM_BUD.A
N/A
Windows
Threat Type: Ransomware
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
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 the initially executed copy of itself.
It encrypts files with specific file extensions.
TECHNICAL DETAILS
484,352 bytes
EXE
Yes
21 Sep 2017
Displays message/message boxes, 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:
- %Application Data%\System32Work\EncryptedFileList.txt - List of encrypted files
- %Application Data%\System32Work\Address.txt - Bitcoin address where the ransom should be paid
- %Application Data%\System32Work\dr - If the ransomware is run while this file exists, it will delete 1000 files
(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 copies of itself into the affected system:
- %Application Data%\Corel\RegisterCGS.exe
- %AppDataLocal%\Corel\CorelCGS.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.. %AppDataLocal% is the Application Data folder found in Local Settings, where it is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local 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\Run
RegisterCGS.exe = %Application Data%\Corel\RegisterCGS.exe
Other System Modifications
This Ransomware adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableTaskMgr = 1
Other Details
This Ransomware does the following:
- Deletes 1000 files if the user restarts the affected system
- Deletes 1 file every hour unil the ransom is paid
- Shows a window that serves a ransom note:
It deletes the initially executed copy of itself
Ransomware Routine
This Ransomware encrypts files with the following extensions:
- .3dm
- .3ds
- .3g2
- .3gp
- .7z
- .7zip
- .aa3
- .aaf
- .accdb
- .aep
- .aepx
- .aet
- .ai
- .ai
- .aif
- .amr
- .apnx
- .as
- .as3
- .asf
- .asp
- .aspx
- .asx
- .avhd
- .avi
- .azw
- .azw1
- .azw3
- .azw4
- .bmp
- .c
- .cdi
- .cer
- .cgi
- .class
- .cpp
- .cs
- .csv
- .dat
- .db
- .dbf
- .der
- .doc
- .docb
- .docm
- .docx
- .dot
- .dotm
- .dotx
- .dwg
- .dxf
- .efx
- .emf
- .eml
- .eps
- .epub
- .fla
- .flv
- .gfx
- .gif
- .gzip
- .h
- .htm
- .html
- .idml
- .iff
- .indb
- .indd
- .indl
- .indt
- .inx
- .iso
- .jar
- .java
- .jfif
- .jge
- .jpe
- .jpeg
- .jpg
- .js
- .json
- .kdbx
- .key
- .key
- .lit
- .m3u
- .m3u8
- .m4a
- .m4u
- .max
- .mdb
- .mid
- .mkv
- .mobi
- .mov
- .mp1
- .mp2
- .mp3
- .mp4
- .mp4v
- .mpa
- .mpeg
- .mpg
- .msg
- .myi
- .nrg
- .nri
- .odc
- .odf
- .odp
- .ods
- .odt
- .p12
- .p7b
- .p7c
- .pbk
- .pdb
- .pem
- .pfx
- .php
- .plb
- .pmd
- .png
- .pot
- .potm
- .potx
- .ppam
- .ppj
- .pps
- .ppsm
- .ppsx
- .ppt
- .pptm
- .pptx
- .prel
- .prproj
- .ps
- .ps
- .psd
- .psd
- .pspimage
- .pst
- .pub
- .pvi
- .py
- .py
- .pyc
- .ra
- .rar
- .raw
- .rb
- .rtf
- .sdf
- .ses
- .sldm
- .sldx
- .sln
- .sql
- .sql
- .svg
- .swf
- .tar
- .tga
- .tif
- .tiff
- .txt
- .vbox
- .vbs
- .vcb
- .vcf
- .vfd
- .vlc
- .vmc
- .vmdk
- .vmsd
- .vmx
- .vob
- .vsdx
- .vsv
- .wav
- .wma
- .wmv
- .work
- .wpd
- .wps
- .xla
- .xlam
- .xll
- .xlm
- .xls
- .xlsb
- .xlsm
- .xlsx
- .xlt
- .xltm
- .xltx
- .xlw
- .xml
- .xqx
- .xqx
- .xvd
- .yuv
- .zip
It avoids encrypting files found in the following folders:
- %Application Data%\System32Work
- C:\Windows
(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 appends the following extension to the file name of the encrypted files:
- .bud
SOLUTION
9.850
13.672.04
21 Sep 2017
13.673.00
22 Sep 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
Restart in Safe Mode
Step 4
Delete this registry value
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\Software\Microsoft\Windows\CurrentVersion\Policies\System
- DisableTaskMgr = 1
- DisableTaskMgr = 1
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- RegisterCGS.exe = %Application Data%\Corel\RegisterCGS.exe
- RegisterCGS.exe = %Application Data%\Corel\RegisterCGS.exe
Step 5
Search and delete these folders
- %Application Data%\Corel
- %AppDataLocal%\Corel
- %Application Data%\System32Work
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as RANSOM_BUD.A. 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 7
Restore encrypted files from backup.
Did this description help? Tell us how we did.