PE_MOFKSYS.D
Windows 2000, Windows XP (32-bit and 64-bit), Windows Server 2003, Windows Vista (32-bit and 64-bit), Windows 7 (32-bit and 64-bit)
Threat Type: File infector
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
Infects files, Dropped by other malware, Downloaded from the Internet
This file infector arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It prepends its codes to target files.
As of this writing, the said sites are inaccessible.
It steals certain information from the system and/or the user.
TECHNICAL DETAILS
2,299,427 bytes
EXE
Yes
29 Sep 2016
Steals information, Downloads files
Arrival Details
This file infector 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 file infector drops the following copies of itself into the affected system:
- %Windows%\spoolsv.exe
- %Windows%\svchost.exe
- %System%\explorer.exe
- %User Profile%\Application Data\icsys.ico.exe
(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)
It drops the following non-malicious files:
- %User Profile%\Application Data\icsys.ico
(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)
Autostart Technique
This file infector adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Svchost = "%Windows%\svchost.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Explorer = "%System%\explorer.exe"
It modifies the following registry entries to ensure it automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = "%Windows%\explorer.exe, %System%\explorer.exe"
(Note: The default value data of the said registry entry is Explorer.exe.)
Other System Modifications
This file infector adds the following registry entries as part of its installation routine:
It modifies the following registry entries to hide files with Hidden attributes:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = "0"
(Note: The default value data of the said registry entry is 1.)
File Infection
This file infector infects the following file types:
- .EXE
It prepends its codes to target files.
This is the Trend Micro detection for files infected by:
- PE_MOFKSYS.D-O
Download Routine
This file infector connects to the following URL(s) to download its component file(s):
- http://xcomd01.{BLOCKED}code.com/svn/trunk/cmsys.gif
- http://xcomd02.{BLOCKED}code.com/svn/trunk/cmsys.gif
- http://dl.{BLOCKED}xusercontent.com/u/276634178/cmsys.gif
As of this writing, the said sites are inaccessible.
Information Theft
This file infector steals the following information:
- Email configurations
- User name
- Password
- Authenticate status
- Use of SSL
- SMTP server
- SMTP port
- recipients
- Websites visited
- Clipboard contents
Drop Points
This file infector uses its own SMTP engine to send the stolen data using the following domain server:
- {BLOCKED}1@gmail.com
- {BLOCKED}01@gmail.com
- {BLOCKED}p.gmail.com
Other Details
This file infector does the following:
- It infects all .EXE files inside the folders that was accessed by the user in all physical and removable drives.
SOLUTION
9.800
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
Identify and delete files detected as PE_MOFKSYS.D using the Recovery Console
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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- Svchost = "%Windows%\svchost.exe"
- Svchost = "%Windows%\svchost.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- Explorer = "%System%\explorer.exe"
- Explorer = "%System%\explorer.exe"
Step 5
Restore this modified 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 NT\CurrentVersion\Winlogon
- Shell = "%Windows%\explorer.exe, %System%\explorer.exe"
- Shell = "%Windows%\explorer.exe, %System%\explorer.exe"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- ShowSuperHidden = "0"
- ShowSuperHidden = "0"
Step 6
Scan your computer with your Trend Micro product to delete files detected as PE_MOFKSYS.D. 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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