TROJ_VTFLOODER.T
W32/Vtflooder.BPO!tr (Fortinet); Trojan.Win32.Vtflooder.bpo (Kaspersky); Trojan.Vtflooder (VBA32)
Windows
![](/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 deletes itself after execution.
TECHNICAL DETAILS
57,628 bytes
EXE
Yes
13 Dec 2016
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 and executes the following files:
- %User Temp%\hdaudio.exe
- %User Temp%\fw.reg
- %User Temp%\ua.reg
- %User Temp%\of.reg
- %User Temp%\coi.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.)
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
hdaudio = "%User Temp%\hdaudio.exe"
Other System Modifications
This Trojan adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Attachments
SaveZoneInformation = "1"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Associations
LowRiskFileTypes = ".avi;.bat;.com;.cmd;.exe;.htm;.html;.lnk;.mpg;.mpeg;.mov;.mp3;.msi;.m3u;.rar;.reg;.txt;.vbs;.wav;.zip;"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
Attachments
SaveZoneInformation = ""
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
Associations
LowRiskFileTypes = ""
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
EnableLUA = "0"
Download Routine
This Trojan saves the files it downloads using the following names:
- %User Temp%\coi.jpg
(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.)
Other Details
This Trojan connects to the following possibly malicious URL:
- http://{BLOCKED}in.com/raw.php?i=gMAV01R2
It deletes itself after execution.
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
Restart in Safe Mode
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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Attachments
- SaveZoneInformation = "1"
- SaveZoneInformation = "1"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Associations
- LowRiskFileTypes = ".avi;.bat;.com;.cmd;.exe;.htm;.html;.lnk;.mpg;.mpeg;.mov;.mp3;.msi;.m3u;.rar;.reg;.txt;.vbs;.wav;.zip;"
- LowRiskFileTypes = ".avi;.bat;.com;.cmd;.exe;.htm;.html;.lnk;.mpg;.mpeg;.mov;.mp3;.msi;.m3u;.rar;.reg;.txt;.vbs;.wav;.zip;"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Attachments
- SaveZoneInformation = ""
- SaveZoneInformation = ""
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Associations
- LowRiskFileTypes = ""
- LowRiskFileTypes = ""
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System
- EnableLUA = "0"
- EnableLUA = "0"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- hdaudio = "%User Temp%\hdaudio.exe"
- hdaudio = "%User Temp%\hdaudio.exe"
Step 5
Search and delete this file
- %User Temp%\hdaudio.exe
- %User Temp%\fw.reg
- %User Temp%\ua.reg
- %User Temp%\of.reg
- %User Temp%\coi.exe
- %User Temp%\coi.jpg
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_VTFLOODER.T. 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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