WORM_MICROFAKE.A

June 16, 2013
 Analysis by: Abraham Latimer Camba
 Modified by: Mark Joseph Manahan
 ALIASES:

Trojan:Win32/Nitol.A (Microsoft), Trojan.Win32.MicroFake (Ikarus), Scar.gen.z (McAfee), Win32/Agent.RNS trojan (ESET)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Copies itself in all available physical drives

This worm 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 connects to a website to send and receive information.

  TECHNICAL DETAILS

File Size:

38,912 bytes

File Type:

DLL, EXE

Memory Resident:

Yes

Initial Samples Received Date:

20 Aug 2012

Payload:

Connects to URLs/IPs, Steals information, Drops files

Arrival Details

This worm 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 worm drops the following copies of itself into the affected system and executes them:

  • %User Temp%\hrp{random}.tmp
  • %User Temp%\SOFTWARE.LOG
  • %System%\hra33.dll
  • %System%\{random}.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.. %System% is the Windows system folder, which is usually C:\Windows\System32.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • Distribublr

Autostart Technique

This worm 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\Distribublr
ImagePath = "%System%\{random}.exe"

Other System Modifications

This worm adds the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Distribublr

Backdoor Routine

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

  • Access URL using Internet Explorer
  • Download and execute arbitrary files
  • Update copy

It connects to the following websites to send and receive information:

  • {BLOCKED}urmama.gicp.net

It posts the following information to its command and control (C&C) server:

  • Computer Name
  • CPU Speed
  • OS Product Name
  • Memory Size

NOTES:

This worm drops the following copy of itself in all folders and .RAR archives in all physical and removable drives containing an .EXE file:

  • lpk.dll

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

9.348.01

FIRST VSAPI PATTERN DATE:

25 Aug 2012

VSAPI OPR PATTERN File:

9.349.00

VSAPI OPR PATTERN Date:

26 Aug 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

Scan your computer with your Trend Micro product and note files detected as WORM_MICROFAKE.A

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Delete this registry key

[ 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\CurrentControlSet\Services
    • Distribublr

Step 5

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