TROJ_CRILOCK.POKQ
Ransom:MSIL/LockScreen.D (Microsoft); RDN/Generic.dx!d2n (McAfee); Trojan.Cryptolocker.P (Symantec); Trojan.MSIL.KillProc.r (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan:MSIL/Ransomware.E (FSecure); Trojan horse MSIL7.AVOP, Trojan horse MSIL7.AVOP.dropper (AVG)
Windows

Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
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
706,048 bytes
EXE
Yes
12 May 2015
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:
- %Application Data%\Microsoft\delta.exe
(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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.)
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
Windows Security = "%Application Data%\Microsoft\delta.exe"
Other System Modifications
This Trojan deletes the following files:
- %Favorites%\MSN.com.url
- %Favorites%\Radio Station Guide.url
- %Favorites%\Links\Customize Links.url
- %Favorites%\Links\Free Hotmail.url
- %Favorites%\Links\Windows Marketplace.url
- %Favorites%\Links\Windows Media.url
- %Favorites%\Links\Windows.url
It adds the following registry keys:
HKEY_CURRENT_USER\Software\DELTA
HKEY_CURRENT_USER\Software\DELTA\
DONE
It adds the following registry entries:
HKEY_CURRENT_USER\Software\DELTA
FilesEncrypted = "+GIrHea+G5+AlQHzIRSF7w=="
HKEY_CURRENT_USER\Software\DELTA
TimeLeft = "AgOj89ofEGZ62zLDU1xxhnij8PFgQ184FzI9uiBktzI="
Dropping Routine
This Trojan drops the following files:
- %Application Data%\Microsoft\pacman.exe
- %Favorites%\MSN.com.url.ENCRYPTED
- %Favorites%\Radio Station Guide.url.ENCRYPTED
- %Favorites%\Links\Customize Links.url.ENCRYPTED
- %Favorites%\Links\Free Hotmail.url.ENCRYPTED
- %Favorites%\Links\Windows Marketplace.url.ENCRYPTED
- %Favorites%\Links\Windows Media.url.ENCRYPTED
- %Favorites%\Links\Windows.url.ENCRYPTED
Other Details
This Trojan connects to the following possibly malicious URL:
- {BLOCKED}0.1
- {BLOCKED}.163.150
- {BLOCKED}.164.249
This report is generated via an automated analysis system.
SOLUTION
9.750
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 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
- DELTA
- In HKEY_CURRENT_USER\Software\DELTA
- DONE
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
- Windows Security = "%Application Data%\Microsoft\delta.exe"
- In HKEY_CURRENT_USER\Software\DELTA
- FilesEncrypted = "+GIrHea+G5+AlQHzIRSF7w=="
- In HKEY_CURRENT_USER\Software\DELTA
- TimeLeft = "AgOj89ofEGZ62zLDU1xxhnij8PFgQ184FzI9uiBktzI="
Step 5
Search and delete these components
- %Application Data%\Microsoft\pacman.exe
- %Favorites%\MSN.com.url.ENCRYPTED
- %Favorites%\Radio Station Guide.url.ENCRYPTED
- %Favorites%\Links\Customize Links.url.ENCRYPTED
- %Favorites%\Links\Free Hotmail.url.ENCRYPTED
- %Favorites%\Links\Windows Marketplace.url.ENCRYPTED
- %Favorites%\Links\Windows Media.url.ENCRYPTED
- %Favorites%\Links\Windows.url.ENCRYPTED
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_CRILOCK.POKQ. 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 7
Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.
- %Favorites%\MSN.com.url
- %Favorites%\Radio Station Guide.url
- %Favorites%\Links\Customize Links.url
- %Favorites%\Links\Free Hotmail.url
- %Favorites%\Links\Windows Marketplace.url
- %Favorites%\Links\Windows Media.url
- %Favorites%\Links\Windows.url
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