TROJ_PASSTEAL.AY
Windows 2000, Windows XP, Windows Server 2003
![](/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.
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:
- %Windows%\drvtsn32.exe
(Note: %Windows% is the Windows folder, which is usually C:\Windows.)
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
Explorer = "%Windows%\drvtsn32.exe"
Other System Modifications
This Trojan deletes the following files:
- DIDNT FIND ANYTHING
- %Windows%\k_log.dat
(Note: %Windows% is the Windows folder, which is usually C:\Windows.)
It adds the following registry keys:
HKEY_CURRENT_USER\Software\NirSoft\
MessenPass
HKEY_CURRENT_USER\Software\NirSoft\
MailPassView
HKEY_CURRENT_USER\Software\NirSoft\
NetPass
It adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Settings
LocationOld = "{malware path and file name}"
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SystemRestore
DisableSR = "1"
Dropping Routine
This Trojan drops the following files:
- %Windows%\ft.dat
- %Windows%\ms.exe
- %Windows%\ml.exe
- %Windows%\pv.exe
- %Windows%\ns.exe
- %Windows%\nkd.nkd
- %Windows%\nkd.dat
- %Windows%\ms.nkd
- %Windows%\ml.nkd
- %Windows%\ns.nkd
- %Windows%\pv.nkd
(Note: %Windows% is the Windows folder, which is usually C:\Windows.)
This report is generated via an automated analysis system.
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.
- In HKEY_CURRENT_USER\Software\NirSoft
- MessenPass
- In HKEY_CURRENT_USER\Software\NirSoft
- MailPassView
- In HKEY_CURRENT_USER\Software\NirSoft
- NetPass
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
- Explorer = "%Windows%\drvtsn32.exe"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Settings
- LocationOld = "{malware path and file name}"
Step 5
Restore these modified registry values
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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SystemRestore
- DisableSR = "1"
Step 6
Search and delete these components
- %Windows%\ft.dat
- %Windows%\ms.exe
- %Windows%\ml.exe
- %Windows%\pv.exe
- %Windows%\ns.exe
- %Windows%\nkd.nkd
- %Windows%\nkd.dat
- %Windows%\ms.nkd
- %Windows%\ml.nkd
- %Windows%\ns.nkd
- %Windows%\pv.nkd
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_PASSTEAL.AY. 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.
Step 8
Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.
- DIDNT FIND ANYTHING
- %Windows%\k_log.dat
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