TROJ_UTOTI.TYZAL
Trojan.Win32.Regrun.psv (Kaspersky), TR/Autoit.768727 (AntiVir), W32/Regrun.PSV!tr (Fortinet)
Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
![](/vinfo/imgFiles/legend.jpg)
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.
It opens a hidden Internet Explorer window.
TECHNICAL DETAILS
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:
- %System%\{Malware Name}
(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
{Malware Name} = "%System%\{Malware} Name"
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 = "Explorer.exe %System%\{Malware Name}"
(Note: The default value data of the said registry entry is "Explorer.exe".)
Other System Modifications
This Trojan adds the following registry entries as part of its installation routine:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
EnableLUA = "0"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
EnableBalloonTips = "0"
Process Termination
This Trojan terminates the following processes if found running in the affected system's memory:
- avp.exe
- wmiav.exe
Other Details
This Trojan connects to the following URL(s) to check for an Internet connection:
- www.google.com
It opens a hidden Internet Explorer window.
It sets the attributes of the following file(s) to Hidden and System:
- %System%\{Malware Name}
(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)
NOTES:
This Trojan sets the system time to September 27, 2019, 09:04 AM. If there is an active Internet connection, it opens the browser to view the non-malicious URL http://site.com/index.php.
SOLUTION
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 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
- {Malware Name} = "%System%\{Malware Name}"
- {Malware Name} = "%System%\{Malware Name}"
- In HKEY_LOCAL_MACHINE\Software\Microsft\Windows\CurrentVersion\Policies\System
- EnableLua = "0"
- EnableLua = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- EnableBalloonTips = "0"
- EnableBalloonTips = "0"
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 NT\CurrentVersion\Winlogon
- From: Shell = "Explorer.exe %System%\{Malware Name}"
To: Shell = "Explorer.exe"
- From: Shell = "Explorer.exe %System%\{Malware Name}"
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_UTOTI.TYZAL. 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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