TROJ_DUNW.A
TrojanDropper:Win32/Ambler.A (Microsoft); generic!bg.hlg (McAfee); Infostealer (Symantec); Trojan.Win32.Generic!BT (Sunbelt); Trojan horse PSW.Generic6.BCSX (AVG)
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.
It deletes itself after execution.
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.
Autostart Technique
This Trojan registers itself as a BHO to ensure its automatic execution every time Internet Explorer is used by adding the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Browser Helper Objects\{2FDA60DF-6D94-4f16-A48C-3C4EC57FEF58}
Other System Modifications
This Trojan deletes the following files:
- %System%\di1.gif
- %System%\dr1.gif
- %System%\cookie1.dat
- %System%\boa1.dat
- %System%\cs.dat
- %System%\ps1.dat
- %System%\rc.dat
- %System%\tb.dr
(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)
It adds the following registry keys:
HKEY_LOCAL_MACHINE\Software\MRSoft
HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Browser Helper Objects
HKEY_CLASSES_ROOT\CLSID\{2FDA60DF-6D94-4f16-A48C-3C4EC57FEF58}
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{2FDA60DF-6D94-4f16-A48C-3C4EC57FEF58}\InprocServer32
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{2FDA60DF-6D94-4f16-A48C-3C4EC57FEF58}\ProgID
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{2FDA60DF-6D94-4f16-A48C-3C4EC57FEF58}\TypeLib
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\MRSoft
Add = "{random values}"
HKEY_LOCAL_MACHINE\SOFTWARE\MRSoft
LN = "ED@BJ_CHAR(0x18)__CHAR(0x19)__CHAR(0x05)_OGG"
HKEY_LOCAL_MACHINE\SOFTWARE\MRSoft
CODIGO = "l%QSV!'SQ:!S.#:#q&!:V#/T:$T#RT QRQ/j"
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{2FDA60DF-6D94-4f16-A48C-3C4EC57FEF58}\InprocServer32
ThreadingModel = "Apartment"
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Enable Browser Extensions = "yes"
Dropping Routine
This Trojan drops the following files:
- %System%\gh.dat
- %System%\nokia32.dll
(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)
Other Details
This Trojan deletes itself after execution.
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
Close all opened browser windows
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_LOCAL_MACHINE\Software
- MRSoft
- In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Explorer
- Browser Helper Objects
- In HKEY_CLASSES_ROOT\CLSID
- {2FDA60DF-6D94-4f16-A48C-3C4EC57FEF58}
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{2FDA60DF-6D94-4f16-A48C-3C4EC57FEF58}
- InprocServer32
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{2FDA60DF-6D94-4f16-A48C-3C4EC57FEF58}
- ProgID
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{2FDA60DF-6D94-4f16-A48C-3C4EC57FEF58}
- TypeLib
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\MRSoft
- Add = "{random values}"
- In HKEY_LOCAL_MACHINE\SOFTWARE\MRSoft
- LN = "ED@BJ_CHAR(0x18)__CHAR(0x19)__CHAR(0x05)_OGG"
- In HKEY_LOCAL_MACHINE\SOFTWARE\MRSoft
- CODIGO = "l%QSV!'SQ:!S.#:#q&!:V#/T:$T#RT QRQ/j"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{2FDA60DF-6D94-4f16-A48C-3C4EC57FEF58}\InprocServer32
- ThreadingModel = "Apartment"
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
- Enable Browser Extensions = "yes"
Step 5
Search and delete these components
- %System%\gh.dat
- %System%\nokia32.dll
Step 6
Scan your computer with your Trend Micro product to delete files detected as TROJ_DUNW.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 this Knowledge Base page for more information.
Step 7
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.
- %System%\di1.gif
- %System%\dr1.gif
- %System%\cookie1.dat
- %System%\boa1.dat
- %System%\cs.dat
- %System%\ps1.dat
- %System%\rc.dat
- %System%\tb.dr
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