BKDR_BYYA.DUKKS
Windows 2000, Windows XP, Windows Server 2003
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Backdoor
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This backdoor 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. It connects to a website to send and receive information.
TECHNICAL DETAILS
40,960 bytes
EXE
Yes
05 Jul 2011
Arrival Details
This backdoor 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 backdoor adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{343F94C0-7BF8-95A0-9892-DE53539F2AF8}
StubPath = "%System%:msfultcomen.exe"
Other System Modifications
This backdoor adds the following registry keys:
HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications
Backdoor Routine
This backdoor opens a hidden Internet Explorer window.
It connects to the following websites to send and receive information:
- {BLOCKED}i.{BLOCKED}s.com
As of this writing, the said sites are inaccessible.
NOTES:
Upon execution, this backdoor copies itself to an alternate data stream (ADS) as the following:
- %System%:msfultcomen.exe
SOLUTION
8.900
8.271.00
06 Jul 2011
Step 1
For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.
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
- Local AppWizard-Generated Applications
- Local AppWizard-Generated Applications
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components
- {343F94C0-7BF8-95A0-9892-DE53539F2AF8}
- {343F94C0-7BF8-95A0-9892-DE53539F2AF8}
Step 4
Scan your computer with your Trend Micro product to delete files detected as BKDR_BYYA.DUKKS. 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.
NOTES:
Delete the ADS file
To delete the ADS file this malware created:
1. Open a command prompt window. Click Start>Run, type CMD, and then press the Enter.
2. At the command prompt, type the following: echo null %System%:msfultcomen.exe
(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003. %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.)
3. Close the command prompt window.
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