BKDR_FYNLOS.SMIA
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: Backdoor
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
Dropped by other malware, Downloaded from the Internet
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 modifies certain registry entries to disable Security Center functions. Doing this allows this malware to execute its routines without being detected.
TECHNICAL DETAILS
674,304 bytes
EXE
Yes
13 Apr 2013
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.
Installation
This backdoor drops the following copies of itself into the affected system:
- %System%\Windupdt\winupdate.exe
(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)
It creates the following folders:
- %System%\Windupdt
(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)
Autostart Technique
This backdoor adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
winupdater = "%System%\Windupdt\winupdate.exe"
It modifies the following registry entries to ensure it automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Userinit = "%System%\userinit.exe,%System%\Windupdt\winupdate.exe"
(Note: The default value data of the said registry entry is %System%\userinit.exe,.)
Other System Modifications
This backdoor adds the following registry keys as part of its installation routine:
HKEY_CURRENT_USER\Software\DC3_FEXEC
It modifies the following registry entries to disable Security Center functions:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AntiVirusDisableNotify = "1"
(Note: The default value data of the said registry entry is 0.)
Other Details
This backdoor connects to the following possibly malicious URL:
- {BLOCKED}ount3.no-ip.org
SOLUTION
9.300
8.236.06
20 Jun 2011
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
Identify and delete files detected as BKDR_FYNLOS.SMIA using either the Startup Disk or Recovery Console
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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.
- In HKEY_CURRENT_USER\Software
- DC3_FEXEC
- DC3_FEXEC
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\Run
- winupdater = "%System%\Windupdt\winupdate.exe"
- winupdater = "%System%\Windupdt\winupdate.exe"
Step 5
Restore this modified 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 NT\CurrentVersion\Winlogon
- From: Userinit = "%System%\userinit.exe,%System%\Windupdt\winupdate.exe"
To: Userinit = %System%\userinit.exe,
- From: Userinit = "%System%\userinit.exe,%System%\Windupdt\winupdate.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
- From: AntiVirusDisableNotify = "1"
To: AntiVirusDisableNotify = 0
- From: AntiVirusDisableNotify = "1"
Step 6
Search and delete this file
- %System%\Windupdt
Step 7
Scan your computer with your Trend Micro product to delete files detected as BKDR_FYNLOS.SMIA. 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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