BKDR_BIFROSE.YIS
Windows 2000, Windows XP, Windows Server 2003
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
342,674 bytes
EXE
Yes
19 Mar 2014
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_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
fbfe3be6db0317403c1acf064d0a9d1e = "%User Profile%\njrat.exe .."
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
fbfe3be6db0317403c1acf064d0a9d1e = "%User Profile%\njrat.exe .."
Other System Modifications
This backdoor deletes the following files:
- %Windows%\Microsoft.NET\Framework\v2.0.50727\config\security.config.cch.1992.123781
- %Windows%\Microsoft.NET\Framework\v2.0.50727\config\enterprisesec.config.cch.1992.123953
- %User Profile%\v2.0.50727.42\security.config.cch.1992.124015
(Note: %Windows% is the Windows folder, which is usually C:\Windows.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)
It adds the following registry keys:
HKEY_CURRENT_USER\Software\fbfe3be6db0317403c1acf064d0a9d1e
It adds the following registry entries:
HKEY_CURRENT_USER\Software\fbfe3be6db0317403c1acf064d0a9d1e
US = "!"
HKEY_CURRENT_USER\Environment
SEE_MASK_NOZONECHECKS = "1"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%User Profile%\njrat.exe = "%User Profile%\njrat.exe:*:Enabled:njrat.exe"
Dropping Routine
This backdoor drops the following files:
- __tmp_rar_sfx_access_check_116125
- Server.exe
- ???? ???.jpg
- %User Profile%\njrat.exe.tmp
- %User Profile%\njrat.exe
- %User Startup%\fbfe3be6db0317403c1acf064d0a9d1e.exe
(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)
This report is generated via an automated analysis system.
SOLUTION
9.300
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
- fbfe3be6db0317403c1acf064d0a9d1e
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
- fbfe3be6db0317403c1acf064d0a9d1e = "%User Profile%\njrat.exe .."
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- fbfe3be6db0317403c1acf064d0a9d1e = "%User Profile%\njrat.exe .."
- In HKEY_CURRENT_USER\Software\fbfe3be6db0317403c1acf064d0a9d1e
- US = "!"
- In HKEY_CURRENT_USER\Environment
- SEE_MASK_NOZONECHECKS = "1"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
- %User Profile%\njrat.exe = "%User Profile%\njrat.exe:*:Enabled:njrat.exe"
Step 5
Search and delete these components
- __tmp_rar_sfx_access_check_116125
- Server.exe
- ???? ???.jpg
- %User Profile%\njrat.exe.tmp
- %User Profile%\njrat.exe
- %User Startup%\fbfe3be6db0317403c1acf064d0a9d1e.exe
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_BIFROSE.YIS. 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.
- %Windows%\Microsoft.NET\Framework\v2.0.50727\config\security.config.cch.1992.123781
- %Windows%\Microsoft.NET\Framework\v2.0.50727\config\enterprisesec.config.cch.1992.123953
- %User Profile%\v2.0.50727.42\security.config.cch.1992.124015
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