Analysis by: Jimelle Monteser
ALIASES:

DDoS:Win32/Nitol.A (Microsoft), Packed.Win32.Klone (Ikarus), Trojan.Win32.Scar.clmn (Kaspersky), Win32/ServStart.AC trojan (NOD32), Backdoor.Graybird (Norton)

 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: 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 the initially executed copy of itself.

  TECHNICAL DETAILS

File Size: 65,204 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 25 Dec 2012

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 copies of itself into the affected system:

  • %System%\{random filename}.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

Other System Modifications

This backdoor adds the following registry entries:

HKEY_LOCAL_MACHINE\System\ControlSet001\
Services\QQ
Description = "Providesktcfdfd dfa dfdfdomain sdffdervefdfr for NdfI securidfwswgty."

Other Details

This backdoor connects to the following possibly malicious URL:

  • http://www.{BLOCKED}.cc/vip63.html

It deletes the initially executed copy of itself

  SOLUTION

Minimum Scan Engine: 9.300
FIRST VSAPI PATTERN FILE: 9.615.01
FIRST VSAPI PATTERN DATE: 25 Dec 2012
VSAPI OPR PATTERN File: 9.616.00
VSAPI OPR PATTERN Date: 26 Dec 2012

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

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_LOCAL_MACHINE\System\ControlSet001\Services\QQ
    • Description = "Providesktcfdfd dfa dfdfdomain sdffdervefdfr for NdfI securidfwswgty."

Step 3

Scan your computer with your Trend Micro product to delete files detected as BKDR_NITOL.JK. 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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