WORM_COMSITPROC.A
Trojan:Win32/Comitsproc!gmbv (Microsoft)
Windows
Threat Type: Worm
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This worm arrives via removable drives. It 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
135,680 bytes
EXE
Yes
25 Jun 2016
Arrival Details
This worm arrives via removable drives.
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 worm drops the following copies of itself into the affected system and executes them:
- %User Temp%\winrar64.exe
(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.)
It terminates the execution of the copy it initially executed and executes the copy it drops instead.
Autostart Technique
This worm adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random} = "%User Temp%\winrar64.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
{random} = "%User Temp%\winrar64.exe"
It drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:
- %User Startup%\{random}.exe
(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)
Other System Modifications
This worm adds the following registry keys:
HKEY_CURRENT_USER\Software\{random}
It adds the following registry entries:
HKEY_CURRENT_USER\Software\{random}
US = @
HKEY_CURRENT_USER\Software\{random}
SEE_MASK_NOZONECHECKS = 1
Propagation
This worm drops the following copy(ies) of itself in all removable drives:
- {Removable Drive Letter}:\{random}.exe
Dropping Routine
This worm drops the following files:
- {malware path}\.tmp
Other Details
This worm connects to the following possibly malicious URL:
- {BLOCKED}.{BLOCKED}.99.31:1190
It does the following:
- Allows itself through the firewall using the following shell command:
- netsh firewall add allowedprogram "%User Temp%\winrar64.exe" "wubrar64.exe" ENABLE
- Drops LNK that targets the malware's copy on removable drives using the name of files inside the removable drive
(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.)
SOLUTION
9.800
12.616.07
27 Jun 2016
12.617.00
28 Jun 2016
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 terminate files detected as WORM_COMSITPROC.A
- Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
- If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
- If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.
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
- {random}
- {random}
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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- {random} = "%User Temp%\winrar64.exe"
- {random} = "%User Temp%\winrar64.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- {random} = "%User Temp%\winrar64.exe"
- {random} = "%User Temp%\winrar64.exe"
Step 6
Search and delete this file
- {malware path}\.tmp
- {Removable drive file's name}.lnk
Step 7
Scan your computer with your Trend Micro product to delete files detected as WORM_COMSITPROC.A. 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.
Did this description help? Tell us how we did.