BKDR_NFLOG.AZ
Trojan.Dropper(Norton),Trojan.Win32.Generic!BT(Sunbelt),Trojan horse Agent4.AKIV(AVG)
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
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 deletes itself after execution.
TECHNICAL DETAILS
27,136 bytes
EXE
Yes
03 Jun 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 files:
- %Temp%\$NtUninstallKB942388$
- %Temp%\MSMAPI.OCX
- %Temp%\NfIpv6.ocx
- %Temp%\YahooCache.ini
(Note: %Temp% is the Windows Temporary folder, which is usually C:\Windows\Temp.)
Autostart Technique
This backdoor registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\IPRIP
Type = "20"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\IPRIP
Start = "2"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\IPRIP
ErrorControl = "1"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\IPRIP
ImagePath = "%SystemRoot%\System32\svchost.exe -k netsvcs"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\IPRIP
DisplayName = "IPv6 Stack Local Support"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\IPRIP
ObjectName = "LocalSystem"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\IPRIP
Description = "Net address translation for IPv6 Protocol"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\IPRIP\Parameters
ServiceDll = " C:\WINDOWS\temp\NfIpv6.ocx"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\IPRIP\Security
Security = {Hex}
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\IPRIP\Enum
0 = "Root\LEGACY_IPRIP\0000"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\IPRIP\Enum
Count = "1"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\IPRIP\Enum
NextInstance = "1"
Other System Modifications
This backdoor adds the following registry keys:
HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Internet Settings\P3P
HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Internet Settings\P3P\History
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\IPRIP
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\IPRIP\Parameters
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\IPRIP\Security
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\IPRIP\Enum
It adds the following registry entries:
HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Internet Settings\Connections
DefaultConnectionSettings = "{hex values}"
HKEY_USERS\.DEFAULT\Software\
Microsoft\Clock
HID = "{Hex value}"
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Internet Settings\
Cache\Paths\path1
CachePath = "LocalService's %Temporary Internet Files%\Content.IE5\Cache1"
(Note: The default value data of the said registry entry is %Temporary Internet Files%\Content.IE5\Cache1.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Internet Settings\
Cache\Paths\path2
CachePath = "LocalService's %Temporary Internet Files%\Content.IE5\Cache2"
(Note: The default value data of the said registry entry is %Temporary Internet Files%\Content.IE5\Cache2.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Internet Settings\
Cache\Paths\path3
CachePath = "LocalService's %Temporary Internet Files%\Content.IE5\Cache3"
(Note: The default value data of the said registry entry is %Temporary Internet Files%\Content.IE5\Cache3.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Internet Settings\
Cache\Paths\path4
CachePath = "LocalService's %Temporary Internet Files%\Content.IE5\Cache4"
(Note: The default value data of the said registry entry is %Temporary Internet Files%\Content.IE5\Cache4.)
HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Internet Settings\Connections
SavedLegacySettings = "{Hex2}"
(Note: The default value data of the said registry entry is {Hex1}.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Internet Settings\
Cache\Paths
Directory = "LocalService's %Temporary Internet Files%\Content.IE5"
(Note: The default value data of the said registry entry is %Temporary Internet Files%\Content.IE5.)
HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Explorer\Shell Folders
AppData = "%System%\config\systemprofile\Application Data"
(Note: The default value data of the said registry entry is NetworkService's %Application Data%\.)
HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Explorer\Shell Folders
Cache = "LocalService's %Temporary Internet Files%\"
(Note: The default value data of the said registry entry is NetworkService's %Temporary Internet Files%\.)
HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Explorer\Shell Folders
History = "LocalService's %Local Settings%\History"
(Note: The default value data of the said registry entry is NetworkService's %Local Settings%\History.)
HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Explorer\Shell Folders
Cookies = "'LocalService's %Cookies%\"
(Note: The default value data of the said registry entry is NetworkService's %Cookies%\.)
Other Details
This backdoor connects to the following possibly malicious URL:
- http://{BLOCKED}1.{BLOCKED}1.6dns6.com
It deletes itself after execution.
SOLUTION
9.300
9.960.05
03 Jun 2013
9.961.00
05 Jun 2013
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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- IPRIP
- IPRIP
- In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings
- P3P
- P3P
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_USERS\.DEFAULT\Software\Microsoft\Clock
- HID = "{hex}"
- HID = "{hex}"
- In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Connections
- DefaultConnectionSettings = "{hex values}"
- DefaultConnectionSettings = "{hex values}"
Step 5
Restore this modified registry value
Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator’s help. You may also check out this Microsoft article first before modifying your computer's registry.
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths
- From: Directory = "LocalService's %Temporary Internet Files%\Content.IE5"
To: Directory = %Temporary Internet Files%\Content.IE5
- From: Directory = "LocalService's %Temporary Internet Files%\Content.IE5"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path1
- From: CachePath = "LocalService's %Temporary Internet Files%\Content.IE5\Cache1"
To: CachePath = %Temporary Internet Files%\Content.IE5\Cache1
- From: CachePath = "LocalService's %Temporary Internet Files%\Content.IE5\Cache1"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path2
- From: CachePath = "LocalService's %Temporary Internet Files%\Content.IE5\Cache2"
To: CachePath = %Temporary Internet Files%\Content.IE5\Cache2
- From: CachePath = "LocalService's %Temporary Internet Files%\Content.IE5\Cache2"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path3
- From: CachePath = "LocalService's %Temporary Internet Files%\Content.IE5\Cache3"
To: CachePath = %Temporary Internet Files%\Content.IE5\Cache3
- From: CachePath = "LocalService's %Temporary Internet Files%\Content.IE5\Cache3"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path4
- From: CachePath = "LocalService's %Temporary Internet Files%\Content.IE5\Cache4"
To: CachePath = %Temporary Internet Files%\Content.IE5\Cache4
- From: CachePath = "LocalService's %Temporary Internet Files%\Content.IE5\Cache4"
- In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Connections
- From: SavedLegacySettings = "{Hex2}"
To: SavedLegacySettings = {Hex1}
- From: SavedLegacySettings = "{Hex2}"
- In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders
- From: AppData = "%System%\config\systemprofile\Application Data"
To: AppData = NetworkService's %Application Data%\
- From: AppData = "%System%\config\systemprofile\Application Data"
- In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders
- From: Cache = "LocalService's %Temporary Internet Files%\"
To: Cache = NetworkService's %Temporary Internet Files%\
- From: Cache = "LocalService's %Temporary Internet Files%\"
- In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders
- From: History = "LocalService's %Local Settings%\History"
To: History = NetworkService's %Local Settings%\History
- From: History = "LocalService's %Local Settings%\History"
- In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders
- From: Cookies = "LocalService's %Cookies%\"
To: Cookies = NetworkService's %Cookies%\
- From: Cookies = "LocalService's %Cookies%\"
Step 6
Search and delete these files
- %Temp%\$NtUninstallKB942388$
- %Temp%\MSMAPI.OCX
- %Temp%\NfIpv6.ocx
- %Temp%\YahooCache.ini
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_NFLOG.AZ. 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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