Worm.Win32.YAHLOVER.A
Trojan:Win32/BeeVry(MICROSOFT); Trojan.Win32.Qhost.afes(KASPERSKY)
Windows
Threat Type: Worm
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This Worm 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
585,728 bytes
EXE
Yes
06 Nov 2019
Arrival Details
This Worm 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:
- %System Root%\WINDOW\System32\smss.exe
- {Every folder}\{Folder name}.exe
- {removable drives}\smss.exe
(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)
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
smss = %System Root%\WINDOW\System32\smss.exe
Other System Modifications
This Worm adds the following registry entries as part of its installation routine:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\wuauserv
Start = 4
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\Sr
Start = 4
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\Sr
ImagePath = \%SystemRoot%\system32\DRIVERS\sr.sys
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\Sr\Parameters
FirstRun = 1
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\Sr
Start = 4
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\Sr
ImagePath = \%SystemRoot%\system32\DRIVERS\sr.sys
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\Sr\Parameters
FirstRun = 1
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\usnjsvc
Start = 3
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\srservice
Start = 4
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\ekrn
Start = 4
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\EhttpSrv
Start = 4
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
EnableLUA = 0
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SystemRestore
DisableSR = 1
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = 2
SOLUTION
9.850
15.478.07
06 Nov 2019
15.479.00
07 Nov 2019
Step 1
Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 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
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
- smss = %System Root%\WINDOW\System32\smss.exe
- smss = %System Root%\WINDOW\System32\smss.exe
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\wuauserv
- Start = 4
- Start = 4
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\Sr
- Start = 4
- Start = 4
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\Sr
- ImagePath = \%SystemRoot%\system32\DRIVERS\sr.sys
- ImagePath = \%SystemRoot%\system32\DRIVERS\sr.sys
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\Sr\Parameters
- FirstRun = 1
- FirstRun = 1
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\Sr
- Start = 4
- Start = 4
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\Sr
- ImagePath = \%SystemRoot%\system32\DRIVERS\sr.sys
- ImagePath = \%SystemRoot%\system32\DRIVERS\sr.sys
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\Sr\Parameters
- FirstRun = 1
- FirstRun = 1
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\usnjsvc
- Start = 3
- Start = 3
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\srservice
- Start = 4
- Start = 4
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\ekrn
- Start = 4
- Start = 4
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\EhttpSrv
- Start = 4
- Start = 4
Step 4
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\CurrentVersion\Policies\System
- From: EnableLUA = 0
To: EnableLUA = 1
- From: EnableLUA = 0
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SystemRestore
- From: DisableSR = 1
To: DisableSR = 0
- From: DisableSR = 1
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: Hidden = 2
To: Hidden = 1
- From: Hidden = 2
Step 5
Search and delete this file
- %System Root%\WINDOW\System32\smss.exe
- {Every folder}\{Folder name}.exe
- {removable drives}\smss.exe
- %System%\drivers\etc\hosts
- %System Root%\WINDOW\System32\Declare.ini
- {removable drives}\autorun.inf
Step 6
Scan your computer with your Trend Micro product to delete files detected as Worm.Win32.YAHLOVER.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 the following Trend Micro Support pages for more information:
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