TROJ_FAKEAV.KLJ
Trojan:Win32/FakeSysdef(Microsoft), FakeAlert-SysDef.ax(McAfee), Riskware/HDDRescue(Fortinet), Trojan.Win32.FakeSysdef(Ikarus)
Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
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.
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 and executes them:
- {All User's Profile}\Application Data\dbheuPYTta.exe
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
dbheuPYTta.exe = "{All User's Profile}\Application Data\dbheuPYTta.exe"
Other System Modifications
This Trojan adds the following registry keys:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Attachments
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Associations
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
It adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableTaskMgr = "1"
HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableTaskMgr = "1"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Attachments
SaveZoneInformation = "1"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Associations
LowRiskFileTypes = ".zip;.rar;.nfo;.txt;.exe;.bat;.com;.cmd;.reg;.msi;.htm;.html;.gif;.bmp;.jpg;.avi;.mpg;.mpeg;.mov;.mp3;.m3u;.wav;.scr;"
HKEY_CURRENT_USER\Software
nsreg = "511fd770"
HKEY_CURRENT_USER\Software
rdc = "1"
It modifies the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = "0"
(Note: The default value data of the said registry entry is 1.)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = "0"
(Note: The default value data of the said registry entry is 1.)
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Download
CheckExeSignatures = "no"
(Note: The default value data of the said registry entry is yes.)
Download Routine
This Trojan connects to the following website(s) to download and execute a malicious file:
- http://www.{BLOCKED}nadug.com/updates/msupdate.dat
- http://www.{BLOCKED}nbbef.com/updates/msupdate.dat
- http://www.{BLOCKED}oveentoes.com/updates/msupdate.dat
It saves the files it downloads using the following names:
- %User Temp%\{random characters}.exe
(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)
Other Details
This Trojan connects to the following possibly malicious URL:
- http://www.{BLOCKED}hva.com/m.php?{random characters}
- http://www.{BLOCKED}iuniv.com/m.php?{random characters}
- http://www.{BLOCKED}lcase.com/m.php?{random characters}
- http://www.{BLOCKED}invanc.com/m.php?{random characters}
- http://www.{BLOCKED}bralire.com/m.php?{random characters}
- http://www.{BLOCKED}enic.com/m.php?{random characters}
- http://www.{BLOCKED}oveentoes.com/?{random characters}
- http://www.{BLOCKED}adug.com/?{random characters}
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 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.
- HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Attachments
- HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Associations
- HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
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_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
- dbheuPYTta.exe = "{All User's Profile}\Application Data\dbheuPYTta.exe"
- dbheuPYTta.exe = "{All User's Profile}\Application Data\dbheuPYTta.exe"
- In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\System
- DisableTaskMgr = "1"
- DisableTaskMgr = "1"
- In HKEY_CURRENT_USER\Software
- nsreg = "511fd770"
- nsreg = "511fd770"
- In HKEY_CURRENT_USER\Software
- rdc = "1"
- rdc = "1"
Step 5
Restore this modified registry value
Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator’s help. You may also check out this Microsoft article first before modifying your computer's registry.
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: Hidden = "0"
To: Hidden = "1"
- From: Hidden = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: ShowSuperHidden = "0"
To: ShowSuperHidden = "1"
- From: ShowSuperHidden = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Download
- From: CheckExeSignatures = "no"
To: CheckExeSignatures = "yes"
- From: CheckExeSignatures = "no"
Step 6
Search and delete this file
- %User Temp%\{random characters}.exe
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_FAKEAV.KLJ. 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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