Analysis by: David John Agni
ALIASES:

Win32/Rovnix.AF (ESET-NOD32), TrojanDownloader:Win32/Rovnix.A (Microsoft)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet

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

It connects to certain websites to send and receive information. However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 163,840 bytes
File Type: DLL
Memory Resident: Yes
Initial Samples Received Date: 15 Dec 2015
Payload: Connects to URLs/IPs, Compromises system security

Arrival Details

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

Installation

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

  • Global\BD{FileSystemName}{VolumeSerialNumber}

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Installer\Products\BB{VolumeSerialNumber}

HKEY_CURRENT_USER\Software\Microsoft\
Installer\Products\BB{VolumeSerialNumber}\
PLUGIN

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Installer\Products\BB{VolumeSerialNumber}
SH1 = "hex values"

HKEY_CURRENT_USER\Software\Microsoft\
Installer\Products\BB{VolumeSerialNumber}
SH2 = "hex values"

HKEY_CURRENT_USER\Software\Microsoft\
Installer\Products\BB{VolumeSerialNumber}
SH3 = "hex values"

Download Routine

This Trojan saves the files it downloads using the following names:

  • %User Temp%\{random filename}

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Other Details

This Trojan connects to the following URL(s) to check for an Internet connection:

  • support.microsoft.com
  • google-public-dns-a.google.com
  • google-public-dns-b.google.com

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

  • http://{BLOCKED}nk.com/login.asp
  • http://{BLOCKED}nk.com/images/transparent.gif
  • http://{BLOCKED}nk.com/images/pixel.gif
  • http://{BLOCKED}nk.com/images/logout.gif
  • http://{BLOCKED}nk.com/download/{8 Characters}.zip

However, as of this writing, the said sites are inaccessible.

NOTES:

It connects to the following NTP servers for clock synchronization between systems:

  • {BLOCKED}.{BLOCKED}.pool.ntp.org
  • {BLOCKED}.{BLOCKED}.pool.ntp.org
  • ntp1.stratum2.ru

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.212.03
FIRST VSAPI PATTERN DATE: 15 Dec 2015
VSAPI OPR PATTERN File: 12.213.00
VSAPI OPR PATTERN Date: 16 Dec 2015

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

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_CURRENT_USER\Software\Microsoft\Installer\Products
    • BB{VolumeSerialNumber}

Step 5

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