WORM_SILLY.WXXZ
Worm.Win32.Foler.a (Tencent); Worm:Win32/Foler.C (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
474,112 bytes
EXE
Yes
14 Dec 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 Profile%\MyHood\{Malware Name}.exe
(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.)
It drops the following component file(s):
- {Removable Drive Letter}:\{Folder Name available on the drive}.exe -> detected as WORM_SILLY.WXXZLDR
This serves as the loader of the dropped malware copy on the removable drive, wherein it contains the name of each folder found on the drive to reinfect a machine.
If no folder was found on the drive, the malware will create a folder "{Removable Drive Letter}:\Data", in order to use it as the dropped loader's name, ie. {Removable Drive Letter}:\Data.exe
It creates the following folders:
- %User Profile%\MyHood
(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 worm drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:
- %User Startup%\ccnfg.lnk -> Shortcut file to the malware's dropped copy
(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.)
Propagation
This worm drops the following copies of itself in all physical and removable drives:
- {Removable Drive Letter}:\{Malware Name}.exe
Other Details
This worm does the following:
- It hides all the folders found on removable drives in order to trick the user on clicking the dropped loader of the malware.
SOLUTION
9.800
12.960.04
14 Dec 2016
12.961.00
15 Dec 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
Remove malware/grayware files dropped/downloaded by WORM_SILLY.WXXZ. (Note: Please skip this step if the threats listed below have already been removed.)
Step 4
Search and delete files detected as WORM_SILLY.WXXZ
Step 5
Search and delete these folders
- %User Profile%\MyHood
Step 6
Search and delete these files
- {Removable Drive Letter}:\{Folder Name available on the drive}.exe
- {Removable Drive Letter}:\{Malware Name}.exe
- {Removable Drive Letter}:\Data.exe
- %User Startup%\ccnfg.lnk
Step 7
Scan your computer with your Trend Micro product to delete files detected as WORM_SILLY.WXXZ. 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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