ALIASES:

NfLog

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

NFLOG variants are capable of executing commands from remote malicious users. Remote malicious users can compromise the affected machine by executing the following commands:

  • Download files

  • Perform Remote Shell

  • Retrieve System Information

  • Update Self

It also capable of stealing information of the affected machine such as the IP configuration, network statistics, running processes, running services and system information.

This Trojan 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.

It deletes itself after execution.

  TECHNICAL DETAILS

Memory Resident: Yes
Payload: Connects to URLs/IPs, Collects system information

Installation

This Trojan drops the following files:

  • %Temp%\$NtUninstallKB942388$ - contains stolen information
  • %Temp%\NfIpv6.ocx - also detected as BKDR_NFLOG
  • %Temp%\checkup.exe - also detected as BKDR_NFLOG
  • %User Temp%\word.doc - non-malicious DOC file
  • %User Temp%\±ØÒª.pdf - non-malicious PDF file
  • %Temp%\YahooCache.ini

(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 injects itself into the following processes as part of its memory residency routine:

  • svchost.exe

Autostart Technique

This Trojan 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 = "{malware path and filename}"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\IPRIP\Security
Security = "{hex values}"

Other System Modifications

This Trojan adds 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

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 Trojan 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:

  • http://www.{BLOCKED}eaderupdating.com/norton/NfCommand.asp?
  • http://www.{BLOCKED}eaderupdating.com/norton/Nfpredown.asp?
  • http://www.{BLOCKED}eaderupdating.com/norton/NfHostInfo.asp?
  • http://www.{BLOCKED}eaderupdating.com/norton/NfCommand.asp?
  • http://www.{BLOCKED}eaderupdating.com/norton/NfStart.asp?
  • http://{BLOCKED}t194.{BLOCKED}n.com/norton/NfCommand.asp
  • http://{BLOCKED}t194.{BLOCKED}n.com/norton/NfHostInfo.as
  • http://{BLOCKED}t194.{BLOCKED}n.com/norton/Nfile.asp
  • http://{BLOCKED}t194.{BLOCKED}n.com/norton/Nfpredown.asp
  • http://{BLOCKED}t194.{BLOCKED}n.com/norton/NfStart.asp
  • http://{BLOCKED}t194.{BLOCKED}n.com/norton/TTip.asp
  • http://{BLOCKED}t.{BLOCKED}025.dns345.cn/norton/TTip.asp
  • http://{BLOCKED}t.{BLOCKED}025.dns345.cn/norton/NfHostInfo.asp
  • http://{BLOCKED}t.{BLOCKED}025.dns345.cn/norton/NfStart.asp
  • http://{BLOCKED}t.{BLOCKED}025.dns345.cn/norton/Nfile.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 Trojan accesses the following websites to download files:

  • http://{BLOCKED}t.{BLOCKED}025.dns345.cn/norton/Nfile.asp
  • http://{BLOCKED}194.{BLOCKED}n.com/norton/Nfile.asp
  • http://www.{BLOCKED}eaderupdating.com/norton/Nfile.asp

It saves the files it downloads using the following names:

  • %Temp%\MSMAPI.OCX - also detected as BKDR_NFLOG

(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.

Other Details

This Trojan requires the existence of the following files to properly run:

  • %Temp%\YahooCache.ini

(Note: %Temp% is the Windows Temporary folder, which is usually C:\Windows\Temp.)

It deletes itself after execution.