TROJ_CRYPTESLA.XXQL
Ransom:Win32/Tescrypt.A (Microsoft); Win32:CryptoWall-U [Trj] (Avast); Trojan-Ransom.Win32.Bitman.my (Kaspersky);
Windows

Threat Type: Trojan
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
Downloaded from the Internet, Dropped by other malware
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.
It connects to certain websites to send and receive information. It deletes the initially executed copy of itself.
TECHNICAL DETAILS
515,072 bytes
EXE
Yes
14 May 2015
Connects to URLs/IPs, Deletes 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 copies of itself into the affected system and executes them:
- %AppDataLocal%\{random filename}.exe
(Note: %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.)
It drops the following files:
- %AppDataLocal%\log.html (list of encrypted files)
- %AppDataLocal%\storage.bin
- %Desktop%\HELP_RESTORE_FILES.bmp
- %Desktop%\HELP_RESTORE_FILES.txt (ransom note)
- %Desktop%\Save_Files.lnk (shortcut to dropped copy)
- {All affected folders}\HELP_RESTORE_FILES_{random letters}.TXT (ransom note)
(Note: %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.. %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.)
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
msconfig = "%AppDataLocal%\{random file name}.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
msconfig = "%AppDataLocal%\{random file name}.exe"
Other System Modifications
This Trojan modifies the following registry entries:
HKEY_CURRENT_USER\Control Panel\Desktop
WallpaperStyle = "0"
(Note: The default value data of the said registry entry is {User preferences}.)
HKEY_CURRENT_USER\Control Panel\Desktop
TileWallPaper = "0"
(Note: The default value data of the said registry entry is {User preferences}.)
HKEY_CURRENT_USER\Control Panel\Desktop
Wallpaper = "%Desktop%\HELP_RESTORE_FILES.bmp"
(Note: The default value data of the said registry entry is {User preferences}.)
Process Termination
This Trojan terminates processes or services that contain any of the following strings if found running in the affected system's memory:
- taskmgr
- procexp
- regedit
- cmd.exe
Other Details
This Trojan connects to the following URL(s) to get the affected system's IP address:
- http://ipinfo.io/ip
It connects to the following website to send and receive information:
- http://{BLOCKED}7s4regu6hn.{BLOCKED}48fn42.com/ping.php
- http://{BLOCKED}7s4regu6hn.{BLOCKED}mr3f43.com/ping.php
- http://{BLOCKED}7s4regu6hn.{BLOCKED}b.blutmagie.de:443
- http://{BLOCKED}7s4regu6hn.{BLOCKED}b.org:443
It encrypts files with the following extensions:
- .3fr
- .7z
- .accdb
- .ai
- .apk
- .arch00
- .arw
- .asset
- .avi
- .bar
- .bay
- .bc6
- .bc7
- .big
- .bik
- .bkf
- .bkp
- .blob
- .bsa
- .cas
- .cdr
- .cer
- .cfr
- .cr2
- .crt
- .crw
- .css
- .csv
- .d3dbsp
- .das
- .dazip
- .db0
- .dba
- .dbf
- .dcr
- .der
- .desc
- .dmp
- .dng
- .doc
- .docm
- .docx
- .dwg
- .dxg
- .epk
- .eps
- .erf
- .esm
- .ff
- .flv
- .forge
- .fos
- .fpk
- .fsh
- .gdb
- .gho
- .hkdb
- .hkx
- .hplg
- .hvpl
- .ibank
- .icxs
- .indd
- .itdb
- .itl
- .itm
- .iwd
- .iwi
- .jpe
- .jpeg
- .jpg
- .js
- .kdb
- .kdc
- .kf
- .layout
- .lbf
- .litemod
- .lrf
- .ltx
- .lvl
- .m2
- .m3u
- .m4a
- .map
- .mcmeta
- .mdb
- .mdbackup
- .mddata
- .mdf
- .mef
- .menu
- .mlx
- .mov
- .mp4
- .mpqge
- .mrwref
- .ncf
- .nrw
- .ntl
- .odb
- .odc
- .odm
- .odp
- .ods
- .odt
- .orf
- .p12
- .p7b
- .p7c
- .pak
- .pdd
- .pef
- .pem
- .pfx
- .pkpass
- .png
- .ppt
- .pptm
- .pptx
- .psd
- .psk
- .pst
- .ptx
- .py
- .qdf
- .qic
- .r3d
- .raf
- .rar
- .raw
- .rb
- .re4
- .rgss3a
- .rim
- .rofl
- .rtf
- .rw2
- .rwl
- .sav
- .sb
- .sid
- .sidd
- .sidn
- .sie
- .sis
- .slm
- .snx
- .sql
- .sr2
- .srf
- .srw
- .sum
- .svg
- .syncdb
- .t12
- .t13
- .tax
- .tor
- .txt
- .upk
- .vcf
- .vdf
- .vfs0
- .vpk
- .vpp_pc
- .vtf
- .w3x
- .wallet
- .wb2
- .wma
- .wmo
- .wmv
- .wotreplay
- .wpd
- .wps
- .x3f
- .xf
- .xlk
- .xls
- .xlsb
- .xlsm
- .xlsx
- .xxx
- .zip
- .ztmp
It deletes the initially executed copy of itself
NOTES:
It appends .exx to the file name of the encrypted files.
It deletes shadow copies by executing the following command:
- %System%\vssadmin.exe delete shadows /all /Quiet
It sets the system's desktop wallpaper to the following image:
It demands payment for using the decryption service:
SOLUTION
9.750
11.670.10
15 May 2015
11.671.00
16 May 2015
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\Run
- msconfig = "%AppDataLocal%\{random file name}.exe"
- msconfig = "%AppDataLocal%\{random file name}.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- msconfig = "%AppDataLocal%\{random file name}.exe"
- msconfig = "%AppDataLocal%\{random file name}.exe"
Step 5
Restore these modified registry values
Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.
- In HKEY_CURRENT_USER\Control Panel\Desktop
- From: WallpaperStyle = "0" To: WallpaperStyle = {User preferences}
- From: WallpaperStyle = "0" To: WallpaperStyle = {User preferences}
- In HKEY_CURRENT_USER\Control Panel\Desktop
- From: TileWallPaper = "0" To: TileWallPaper = {User preferences}
- From: TileWallPaper = "0" To: TileWallPaper = {User preferences}
- In HKEY_CURRENT_USER\Control Panel\Desktop
- From: Wallpaper = "%Desktop%\HELP_RESTORE_FILES.bmp" To: Wallpaper = {User preferences}
- From: Wallpaper = "%Desktop%\HELP_RESTORE_FILES.bmp" To: Wallpaper = {User preferences}
Step 6
Search and delete these files
- %AppDataLocal%\log.html
- %AppDataLocal%\storage.bin
- %Desktop%\HELP_RESTORE_FILES.bmp
- %Desktop%\HELP_RESTORE_FILES.txt
- %Desktop%\Save_Files.lnk
- {All affected folders}\HELP_RESTORE_FILES_{random letters}.TXT
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_CRYPTESLA.XXQL. 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.
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