TROJ_CRILOCK.YMS
Trojan:Win32/Crilock (Microsoft),Trojan-Ransom.Win32.Cryptolocker.bt(Kaspersky), W32/Cryptolocker.BT!tr(Fortinet)
Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
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.
TECHNICAL DETAILS
827,392 bytes
EXE
Yes
15 May 2014
Connects to URLs/IPs, 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 copies of itself into the affected system and executes them:
- %AppDataLocal%\{random filename}.exe
(Note: %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local on Windows Vista and 7.)
It drops the following files:
- %Desktop%\{random filename}.bmp
(Note: %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\Desktop on Windows Vista and 7.)
It adds the following mutexes to ensure that only one of its copies runs at any one time:
- Global\{random characters}
- Local\{random characters}
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
CryptoLocker = "%AppDataLocal%\{random filename}.exe"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
*CryptoLocker = "%AppDataLocal%\{random filename}.exe"
Other System Modifications
This Trojan adds the following registry keys:
HKEY_CURRENT_USER\Software\CryptoLocker_{random 4 characters}
HKEY_CURRENT_USER\Software\CryptoLocker_{random 4 characters}\
Files
It adds the following registry entries:
HKEY_CURRENT_USER\Software\CryptoLocker_{random 4 characters}
Wallpaper = "{hex values}"
HKEY_CURRENT_USER\Software\CryptoLocker_{random 4 characters}
PublicKey = “{hex values}"
HKEY_CURRENT_USER\Software\CryptoLocker_{random 4 characters}\
Files
{path and file name of encrypted file} = “{hex value}”
HKEY_CURRENT_USER\Software\CryptoLocker_{random 4 characters}
VersionInfo = "{hex values}"
NOTES:
This Trojan attempts to download the key to be used in encrypting files by connecting to randomly generated domains:
- http://{random characters}/biz/home
- http://{random characters}/ru/home
- http://{random characters}/org/home
- http://{random characters}/co.uk/home
- http://{random characters}/info/home
- http://{random characters}/com/home
- http://{random characters}/net/home
It encrypts files with the following extensions:
- *.3fr
- *.3gp
- *.accdb
- *.ai
- *.arw
- *.bay
- *.cdr
- *.cer
- *.cr2
- *.crt
- *.crw
- *.dbf
- *.dcr
- *.der
- *.dng
- *.doc
- *.docm
- *.docx
- *.dwg
- *.dxf
- *.dxg
- *.eps
- *.erf
- *.img
- *.jpg
- *.indd
- *.jpe
- *.jpg
- *.kdc
- *.m4v
- *.mdb
- *.mdf
- *.mef
- *.mov
- *.mp4
- *.mrw
- *.nef
- *.nrw
- *.odb
- *.odc
- *.odm
- *.odp
- *.ods
- *.odt
- *.orf
- *.p12
- *.p7b
- *.p7c
- *.pdd
- *.pef
- *.pem
- *.pfx
- *.ppt
- *.pptm
- *.pptx
- *.psd
- *.pst
- *.ptx
- *.r3d
- *.raf
- *.raw
- *.rtf
- *.rw2
- *.rwl
- *.sr2
- *.srf
- *.srw
- *.wb2
- *.wpd
- *.wps
- *.x3f
- *.xlk
- *.xls
- *.xlsb
- *.xlsm
- *.xlsx
After successfully encrypting files on the targeted system, it replaces the wallpaper with another image:
It demands users to pay a fine in to restore affected files:
Users are encouraged to pay via any of the following payment methods:
- Bitcoin
- MoneyPak
Note that once the files are encrypted, the files can no longer be restored. Payment does not always guarantee file restoration.
SOLUTION
9.300
10.796.03
15 May 2014
10.797.00
15 May 2014
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
Restart in Safe Mode
Step 3
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
- CryptoLocker = "%AppDataLocal%\{random filename}.exe"
- CryptoLocker = "%AppDataLocal%\{random filename}.exe"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
- *CryptoLocker = "%AppDataLocal%\{random filename}.exe"
- *CryptoLocker = "%AppDataLocal%\{random filename}.exe"
Step 4
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_CURRENT_USER\Software
- CryptoLocker_{random 4 characters}
- CryptoLocker_{random 4 characters}
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_CRILOCK.YMS. 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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