BKDR_NFLOG.ER
Backdoor:Win32/Parcim.A(Microsoft)
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
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 executes commands from a remote malicious user, effectively compromising the affected system.
It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.
TECHNICAL DETAILS
75,776 bytes
EXE
Yes
28 Jan 2014
Connects to URLs/IPs, Steals information
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 file(s)/component(s):
- %Temp%\YahooCache.ini
- %Temp%\$NtUninstallKB942388$ - Contains stolen information
- %User Temp%\iexpl001.tmp - also detected as BKDR_NFLOG.ER
- %Temp%\NfIpv6.ocx - also detected as BKDR_NFLOG.ER
(Note: %Temp% is the Windows Temporary folder, which is usually C:\Windows\Temp.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)
It drops the following non-malicious file:
- %User Temp%\iexpl001.tmpcmd.exe - copy of cmd.exe
(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)
It injects codes into the following process(es):
- svchost.exe
Autostart Technique
This backdoor registers its dropped component as a system service to ensure its automatic execution at every system startup. It does this by creating the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\IPRIP
ImagePath = "%System%\svchost.exe -k netsvcs"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\IPRIP
DisplayName = "IPv6 Stack Local Support"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\IPRIP
Description = "Net address translation for IPv6 Protocol"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\IPRIP\Parameters
ServiceDll = "%Temp%\NfIpv6.ocx"
It registers its dropped component as a system service to ensure its automatic execution at every system startup. It does this by creating the following registry keys:
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
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_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Internet Settings\Connections
It adds the following registry entries:
HKEY_USERS\.DEFAULT\Software\
Microsoft\Clock
HID = "{hex values}"
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Internet Settings\
Cache\Paths
Directory = "NetworkService's %Temporary Internet Files%\Content.IE5"
(Note: The default value data of the said registry entry is %Temporary Internet Files%\Content.IE5.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Internet Settings\
Cache\Paths\path1
CachePath = "NetworkService'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 = "NetworkService'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 = "NetworkService'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 = "NetworkService's %Temporary Internet Files%\Content.IE5\Cache4"
(Note: The default value data of the said registry entry is %Temporary Internet Files%\Content.IE5\Cache4.)
Backdoor Routine
This backdoor executes the following commands from a remote malicious user:
- Download files
- Perform remote shell
- Retrieve system information
- Update self
It connects to the following URL(s) to send and receive commands from a remote malicious user:
- www.{BLOCKED}elev.com/norton/NfStart.asp
- www.{BLOCKED}elev.com/norton/NfHostInfo.asp
- www.{BLOCKED}elev.com/norton/TTip.asp
- www.{BLOCKED}elev.com/norton/NfCommand.asp
- www.{BLOCKED}elev.com/norton/Nfpredown.asp
It posts the following information to its command and control (C&C) server:
- IP configuration
- Network statistics
- Running processes
- Running services
- System information
Download Routine
This backdoor connects to the following website(s) to download and execute a malicious file:
- www.{BLOCKED}elev.com/norton/Nfile.asp
It saves the files it downloads using the following names:
- %Temp%\MSMAPI.OCX - also detected as BKDR_NFLOG.ER
(Note: %Temp% is the Windows Temporary folder, which is usually C:\Windows\Temp.)
It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.
NOTES:
This backdoor sends IP address and infection time to report system infection. It sends this information to the following URL via HTTP post:
- www.{BLOCKED}elev.com/norton/NfStart.asp
SOLUTION
9.700
10.538.02
13 Jan 2014
10.539.00
14 Jan 2014
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. 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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- IPRIP
- IPRIP
- In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings
- P3P
- P3P
- In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings
- Connections
- Connections
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 values}"
- HID = "{hex values}"
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\CurrentVersion\Internet Settings\Cache\Paths
- From: Directory = "NetworkService's %Temporary Internet Files%\Content.IE5"
To: Directory = %Temporary Internet Files%\Content.IE5
- From: Directory = "NetworkService's %Temporary Internet Files%\Content.IE5"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path1
- From: CachePath = "NetworkService's %Temporary Internet Files%\Content.IE5\Cache1"
To: CachePath = %Temporary Internet Files%\Content.IE5\Cache1
- From: CachePath = "NetworkService's %Temporary Internet Files%\Content.IE5\Cache1"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path2
- From: CachePath = "NetworkService's %Temporary Internet Files%\Content.IE5\Cache2"
To: CachePath = %Temporary Internet Files%\Content.IE5\Cache2
- From: CachePath = "NetworkService's %Temporary Internet Files%\Content.IE5\Cache2"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path3
- From: CachePath = "NetworkService's %Temporary Internet Files%\Content.IE5\Cache3"
To: CachePath = %Temporary Internet Files%\Content.IE5\Cache3
- From: CachePath = "NetworkService's %Temporary Internet Files%\Content.IE5\Cache3"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths\path4
- From: CachePath = "NetworkService's %Temporary Internet Files%\Content.IE5\Cache4"
To: CachePath = %Temporary Internet Files%\Content.IE5\Cache4
- From: CachePath = "NetworkService's %Temporary Internet Files%\Content.IE5\Cache4"
Step 6
Search and delete these files
- %Temp%\YahooCache.ini
- %Temp%\$NtUninstallKB942388$
- %User Temp%\iexpl001.tmp
- %Temp%\NfIpv6.ocx
- %Temp%\MSMAPI.OCX
- %User Temp%\iexpl001.tmpcmd.exe
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_NFLOG.ER. 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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