TROJ_CRILOCK.YNB
Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It modifies the Internet Explorer Zone Settings.
TECHNICAL DETAILS
Arrival Details
This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users.
It 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 a copy of itself in the following folders using different file names:
- %Windows%\{random value}.exe
(Note: %Windows% is the Windows folder, which is usually C:\Windows.)
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
{random characters} = "%Windows%\{random characters}.exe"
Other System Modifications
This Trojan adds the following registry keys:
HKEY_CURRENT_USER\Software\Bit Torrent Application\
Configuration
It adds the following registry entries:
HKEY_CURRENT_USER\Software\Bit Torrent Application\
Configuration
01000000 = "{random values}"
HKEY_CURRENT_USER\Software\Bit Torrent Application\
Configuration
02000000 = "{random values}"
HKEY_CURRENT_USER\Software\Bit Torrent Application\
Configuration
03000000 = "{random values}"
HKEY_CURRENT_USER\Software\Bit Torrent Application\
Configuration
00000000 = "{random values}"
Web Browser Home Page and Search Page Modification
This Trojan modifies the Internet Explorer Zone Settings.
NOTES:
This Trojan may connect to the URL http://{BLOCKED}cription/gate.php to download the key used in encrypting the files.
The .eml file where the malware may arrive contains the following links where the malware can be downloaded:
- http://{BLOCKED}st.org/eparcel/service.php?id=85925730
- http://{BLOCKED}st.org/eparcel/service.php?id=25189924
- http://{BLOCKED}st.org/unsubscrube.php?id=33321132
The URLs above are inaccessible as of this writing.
It connects to localhost to check Internet connection.
SOLUTION
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 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\Bit Torrent Application
- Configuration
Step 5
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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- {random characters} = %Windows%\{random characters}.exe
- {random characters} = %Windows%\{random characters}.exe
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_CRILOCK.YNB. 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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