TROJ_CRYPTESLA.CAG
Win32:Crypt-RXH [Trj] (Avast); Win32/Filecoder.EM (ESET-NOD32); Trojan.Agent.ED (Malwarebytes)
Windows
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Trojan
Destructiveness: Yes
Encrypted: Yes
In the wild: Yes
OVERVIEW
Downloaded from the Internet, Dropped by other malware
This crypto-ransomware is one of the malware payloads of Fiesta exploit kit. Typically, exploit kits are used to deliver or spread threats.
To get a one-glance comprehensive view of the behavior of this Trojan, refer to the Threat Diagram shown below.
![](http://www.trendmicro.com/vinfo/resources/images/TROJ_CRYPTESLA_CAG.jpg)
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 may be dropped by other malware.
It connects to certain websites to send and receive information.
TECHNICAL DETAILS
332,313 bytes
EXE
Yes
18 Mar 2015
Encrypts files, Connects to URLs/IPs
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.
It may be dropped by other malware.
Installation
This Trojan drops the following copies of itself into the affected system and executes them:
- %Application Data%\{random filename}.exe
(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)
It drops the following files:
- %Application Data%\key.dat
- %Application Data%\log.html (list of all encrypted files)
- %Desktop%\HELP_RESTORE_FILES.bmp
- %Desktop%\HELP_RESTORE_FILES.txt
- %Desktop%\CryptoLocker.lnk (shortcut for dropped copy)
(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\Desktop on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)
It adds the following mutexes to ensure that only one of its copies runs at any one time:
- System1230123
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
svv_e = "%Application Data%\{random filename}.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\RunOnce
*svv_e = "%Application Data%\{random filename}.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:
- cmd.exe
- msconfig
- regedit
- procexp
- taskmgr
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:
- https://{BLOCKED}ib47vlep5o.tor2web.fi
- https://{BLOCKED}ib47vlep5o.tor2web.blutmagie.de
- https://{BLOCKED}ib47vlep5o.42kjb11.net
- https://{BLOCKED}q26q2h4jkzj.2kjb10.net
NOTES:
It encrypts files with the following extensions in all folders found in the physical drives and appends .ECC as the new file extension of the encrypted files:
- .sql
- .mp4
- .7z
- .rar
- .m4a
- .wma
- .avi
- .wmv
- .csv
- .d3dbsp
- .zip
- .sie
- .sum
- .ibank
- .t13
- .t12
- .qdf
- .gdb
- .tax
- .pkpass
- .bc6
- .bc7
- .bkp
- .qic
- .bkf
- .sidn
- .sidd
- .mddata
- .itl
- .itdb
- .icxs
- .hvpl
- .hplg
- .hkdb
- .mdbackup
- .syncdb
- .gho
- .cas
- .svg
- .map
- .wmo
- .itm
- .sb
- .fos
- .mov
- .vdf
- .ztmp
- .sis
- .sid
- .ncf
- .menu
- .layout
- .dmp
- .blob
- .esm
- .vcf
- .vtf
- .dazip
- .fpk
- .mlx
- .kf
- .iwd
- .vpk
- .tor
- .psk
- .rim
- .w3x
- .fsh
- .ntl
- .arch00
- .lvl
- .snx
- .cfr
- .ff
- .vpp_pc
- .lrf
- .m2
- .mcmeta
- .vfs0
- .mpqge
- .kdb
- .db0
- .db
- .rofl
- .hkx
- .bar
- .upk
- .das
- .iwi
- .litemod
- .asset
- .forge
- .ltx
- .bsa
- .apk
- .re4
- .sav
- .lbf
- .slm
- .bik
- .epk
- .rgss3a
- .pak
- .big
- .unity3d
- .wotreplay
- .xxx
- .desc
- .py
- .m3u
- .flv
- .js
- .css
- .rb
- .png
- .jpeg
- .txt
- .p7c
- .p7b
- .p12
- .pfx
- .pem
- .crt
- .cer
- .der
- .x3f
- .srw
- .pef
- .ptx
- .r3d
- .rw2
- .rwl
- .raw
- .raf
- .orf
- .nrw
- .mrwref
- .mef
- .erf
- .kdc
- .dcr
- .cr2
- .crw
- .bay
- .sr2
- .srf
- .arw
- .3fr
- .dng
- .jpe
- .jp
- .cdr
- .indd
- .ai
- .eps
- .pdd
- .psd
- .dbf
- .mdf
- .wb2
- .rtf
- .wpd
- .dxg
- .xf
- .dwg
- .pst
- .accdb
- .mdb
- .pptm
- .pptx
- .ppt
- .xlk
- .xlsb
- .xlsm
- .xlsx
- .xls
- .wps
- .docm
- .docx
- .doc
- .odb
- .odc
- .odm
- .odp
- .ods
- .odt
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 decryption service:
SOLUTION
9.750
11.561.00
26 Mar 2015
11.561.00
26 Mar 2015
Step 1
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 2
Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.
Step 3
Scan your computer with your Trend Micro product and note files detected as TROJ_CRYPTESLA.CAG
Step 4
Restart in Safe Mode
Step 5
Delete this registry key
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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- svv_e = "%Application Data%\{random filename}.exe"
- svv_e = "%Application Data%\{random filename}.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce
- *svv_e = "%Application Data%\{random filename}.exe"
- *svv_e = "%Application Data%\{random filename}.exe"
Step 6
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.
- From: WallpaperStyle = "0"
- To: WallpaperStyle = "{User Preferences}"
- From: TileWallpaper = "0"
- To: TileWallpaper = "{User Preferences}"
- From: Wallpaper = "%Desktop%\HELP_TO_SAVE_YOUR_FILES.bmp"
- To: Wallpaper = "{User Preferences}"
Step 7
Search and delete these files
- %Application Data%\key.dat
- %Application Data%\log.html
- %Desktop%\HELP_RESTORE_FILES.bmp
- %Desktop%\HELP_RESTORE_FILES.txt
- %Desktop%\CryptoLocker.lnk
Step 8
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_CRYPTESLA.CAG. 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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