RANSOM_BART.A
Trojan:Win32/Dynamer!ac (Microsoft); Ransom.Bart (Malwarebytes); Trojan-Ransom.Win32.Bart.b (Kaspersky)
Windows

Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
Downloaded from the Internet
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
351,744 bytes
EXE
No
27 Jun 2016
Displays message/message boxes, Encrypts files
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 the following files:
- {folders containing encrypted files}\recover.txt - ransom note
- %Desktop%\recover.bmp - image used as wallpaper
(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 and executes the following files:
- %Desktop%\recover.txt - ransom note
(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.)
Other System Modifications
This Trojan modifies the following file(s):
- It encrypts files in fixed, network, and removable drives, as well as files in RAM disk drives.
- It adds the target files to an archive (.zip) with a password, then renames the archive with: {target’s original filename and extension}.bart.zip
It adds the following registry entries as part of its installation routine:
HKEY_CURRENT_USER\Control Panel\Desktop
Wallpaper = %Desktop%\recover.bmp
It modifies the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = 2
(Note: The default value data of the said registry entry is 1.)
It sets the system's desktop wallpaper to the following image:
Other Details
This Trojan encrypts files with the following extensions:
- .avi
- .bak
- .bat
- .bmp
- .brd
- .bz2
- .cgm
- .class
- .cmd
- .cpp
- .crt
- .cs
- .csr
- .CSV
- .db
- .dbf
- .dch
- .dif
- .dip
- .djv
- .djvu
- .DOC
- .docb
- .docm
- .docx
- .DOT
- .dotm
- .dotx
- .fla
- .flv
- .frm
- .gif
- .gpg
- .gz
- .hwp
- .ibd
- .jar
- .java
- .jpeg
- .jpg
- .js
- .key
- .lay
- .lay6
- .ldf
- .m3u
- .m4u
- .max
- .mdb
- .mdf
- .mid
- .mkv
- .mm
- .mov
- .mp3
- .mp4
- .mpeg
- .mpg
- .ms11
- .MYD
- .MYI
- .n64
- .NEF
- .odb
- .odg
- .odp
- .ods
- .odt
- .otg
- .otp
- .ots
- .ott
- .p
- .p12
- .PAQ
- .pas
- .pem
- .php
- .png
- .pot
- .potm
- .potx
- .ppam
- .pps
- .ppsm
- .ppsx
- .PPT
- .pptm
- .pptx
- .psd
- .qcow2
- .rar
- .raw
- .rb
- .RTF
- .sch
- .sh
- .sldm
- .sldx
- .slk
- .sq
- .SQLITE3
- .SQLITEDB
- .stc
- .std
- .sti
- .stw
- .svg
- .swf
- .sxc
- .sxd
- .sxi
- .sxm
- .sxw
- .tar
- .tar
- .tbk
- .tgz
- .tif
- .tiff
- .txt
- .uop
- .uot
- .vb
- .vbs
- .vdi
- .vmdk
- .vmx
- .vob
- .wav
- .wb2
- .wk1
- .wks
- .wma
- .wmv
- .xlc
- .xlm
- .XLS
- .xlsb
- .xlsm
- .xlsx
- .xlt
- .xltm
- .xltx
- .xlw
- .xm
- .zip
- .123
- .602
- .3dm
- .3ds
- .3g2
- .3gp
- .7z
- .aes
- .ARC
- .asc
- .asf
- .asm
- .asp
It does the following:
- It prevents encrypting files containing any of the strings in its full path name:
- $Recycle.Bin
- AppData
- Application Data
- Boot
- PerfLogs
- Program Files
- ProgramData
- Recovery
- System Volume Information
- temp
- Windows
- winnt
NOTES:
This ransomware uses the following ransom note:

SOLUTION
9.800
12.616.07
27 Jun 2016
12.617.00
28 Jun 2016
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\Control Panel\Desktop
- Wallpaper = %Desktop%\recover.bmp
- Wallpaper = %Desktop%\recover.bmp
Step 5
Restore this modified 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\Explorer\Advanced
- From: Hidden = 2
To: Hidden = 1
- From: Hidden = 2
Step 6
Search and delete these files
- {folders containing encrypted files}\recover.txt
- %Desktop%\recover.txt
- %Desktop%\recover.bmp
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as RANSOM_BART.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 8
Restore encrypted files from backup.
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