BKDR_NFLOG.A

October 09, 2012
 Analysis by: Kathleen Notario
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This backdoor may be downloaded by other malware/grayware from remote sites.

It does not have any propagation routine.

It executes commands from a remote malicious user, effectively compromising the affected system.

It does not drop any other file.

It does not have any downloading capability.

It does not have any information-stealing capability.

  TECHNICAL DETAILS

File Size:

60,416 bytes

File Type:

DLL

Initial Samples Received Date:

13 Oct 2011

Arrival Details

This backdoor may be downloaded by the following malware/grayware from remote sites:

  • TROJ_NFDLOAD.A

It may be downloaded from the following remote site(s):

  • http://www.{BLOCKED}fa.com/NfLog/Nfile.asp

Other System Modifications

This backdoor adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Clock
HID = {hex value}

Propagation

This backdoor does not have any propagation routine.

Backdoor Routine

This backdoor executes the following commands from a remote malicious user:

  • Download files
  • Execute command shell
  • Retrieve drive information

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • http://www.{BLOCKED}fa.com

Dropping Routine

This backdoor does not drop any other file.

Download Routine

This backdoor does not have any downloading capability.

Information Theft

This backdoor does not have any information-stealing capability.

NOTES:

Rootkit Capabilities

This malware does not have rootkit capabilities.

Other Details

It reports system infection by sending IP address and infection time to the following URL via HTTP post:

  • http://www.{BLOCKED}fa.com/NfLog/NfStart.asp

It may also perform HTTP post requests to the following URLs depending on the backdoor command:

  • http://www.{BLOCKED}fa.com/NfLog/NfCommand.asp
  • http://www.{BLOCKED}fa.com/NfLog/NfGetecho.asp
  • http://www.{BLOCKED}fa.com/NfLog/Nfdown.asp
  • http://www.{BLOCKED}fa.com/NfLog/Nfpredown.asp
  • http://www.{BLOCKED}fa.com/NfLog/NfFile.asp
  • http://www.{BLOCKED}fa.com/NfLog/NfCommand.asp
  • http://www.{BLOCKED}fa.com/NfLog/NfUpda.asp

This malware does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

8.496.02

FIRST VSAPI PATTERN DATE:

14 Oct 2011

VSAPI OPR PATTERN File:

8.497.00

VSAPI OPR PATTERN Date:

14 Oct 2011

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

Remove the malware/grayware file that dropped/downloaded BKDR_NFLOG.A

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Delete this registry value

[ Learn More ]

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\Clock
    • HID = {hex value}

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_NFLOG.A. 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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