BKDR_FLODER.BG
TrojanDownloader:Win32/EyeStye.D (Microsoft); W32.Pilleuz (Symantec); Backdoor.Win32.Floder.fdq (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan.Generic.6942207 (FSecure)
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.
TECHNICAL DETAILS
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 creates the following folders:
- %User Profile%\Application Data\VMware
- %User Profile%\Microsoft\Dr Watson
- %Windows%\SoftwareDistribution
- %Windows%\SoftwareDistribution\DataStore\Logs\
- %Windows%\SoftwareDistribution\DataStore
(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.. %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)
Other System Modifications
This backdoor deletes the following files:
- %Windows%\SoftwareDistribution\DataStore\Logs\edbtmp.log
(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Eventlog\Application\
ESENT
EventMessageFile = "%System%\ESENT.dll"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Eventlog\Application\
ESENT
CategoryMessageFile = "%System%\ESENT.dll"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Eventlog\Application\
ESENT
CategoryCount = 1
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Eventlog\Application\
ESENT
TypesSupported = 7
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DrWatson
NumberOfCrashes = 1
It deletes the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
PCHealth\ErrorReporting\DW
Dropping Routine
This backdoor drops the following files:
- %User Profile%\Dr Watson\drwtsn32.log
- %User Profile%\Dr Watson\user.dmp
(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)
Other Details
This backdoor connects to the following possibly malicious URL:
- http://update.{BLOCKED}r.net/qx200.exe
This report is generated via an automated analysis system.
SOLUTION
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
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\SYSTEM\ControlSet001\Services\Eventlog\Application\ESENT
- EventMessageFile="%System%\ESENT.dll"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Eventlog\Application\ESENT
- CategoryMessageFile="%System%\ESENT.dll"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Eventlog\Application\ESENT
- CategoryCount=1
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Eventlog\Application\ESENT
- TypesSupported=7
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DrWatson
- NumberOfCrashes=1
Step 3
Search and delete these folders
- %User Profile%\Application Data\VMware
- %User Profile%\Microsoft\Dr Watson
- %Windows%\SoftwareDistribution
- %Windows%\SoftwareDistribution\DataStore\Logs\
- %Windows%\SoftwareDistribution\DataStore
Step 4
Search and delete these files
- %User Profile%\Dr Watson\drwtsn32.log
- %User Profile%\Dr Watson\user.dmp
Step 5
Scan your computer with your Trend Micro product to delete files detected as BKDR_FLODER.BG. 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 6
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. %Windows%\SoftwareDistribution\DataStore\Logs\edbtmp.log
Step 7
Restore these deleted registry keys/values from backup
*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\PCHealth\ErrorReporting
- DW
Did this description help? Tell us how we did.