Threat Encyclopedia

BKDR_ROMBERTIK.A

Publish date: May 06, 2015

ANALYSIS BY

Cris Nowell Pantanilla


PLATFORM:

Windows

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

  • Threat Type:Backdoor

  • Destructiveness:No

  • Encrypted: Yes

  • In the wild: Yes

OVERVIEW

Infection Channel:

Spammed via email


This malware hooks itself onto certain browsers in the affected system for purposes of information theft. It also wipes the affected system's Master Boot Record(MBR) if it detects security detection efforts, which can cause loss of sensitive data/critical documents. Users with systems affected by this malware may have their security and critical data compromised.

To get a one-glance comprehensive view of the behavior of this Backdoor, refer to the Threat Diagram shown below.

This backdoor arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

It connects to a website to send and receive information.

TECHNICAL DETAILS

File Size:

1,294,848 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

12 Jan 2015

Payload:

Connects to URLs/IPs, Drops files

Arrival Details

This backdoor arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

Installation

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

  • %Application Data%\rsr\yfoye.exe

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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.)

It drops the following files:

  • %Application Data%\rsr\yfoye.bat

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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.)

Autostart Technique

This backdoor drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:

  • %User Startup%\fgf.vbs

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)

Backdoor Routine

This backdoor connects to the following websites to send and receive information:

  • www.{BLOCKED}os.org.in/don1/gate.php

NOTES:

It injects itself to the following web browser to monitor the user's web activities:

  • iexplore.exe
  • firefox.exe
  • chrome.exe

Anti-Analysis Features:

In an virtual machine, it performs a looping process. This causes the sandbox to create very large logs that may eventually cause the system to crash.

Rather than performing its malicious routines, it instead displays a normal window if its filename contains any of the following strings:

  • malwar
  • file.
  • sandb
  • viru
  • sampl

This malware contains anti-analysis functions that, when triggered, attempts to overwrites the Master Boot Record (MBR) of the affected system. If it fails, it attempts to encrypt the files found in the user's home folder. This renders the machine unusable or have limited functionality.

SOLUTION

Minimum Scan Engine:

9.750

FIRST VSAPI PATTERN FILE:

11.412.02

FIRST VSAPI PATTERN DATE:

12 Jan 2015

VSAPI OPR PATTERN File:

11.413.00

VSAPI OPR PATTERN Date:

13 Jan 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

Search and delete this file

[ Learn More ]
There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %Application Data%\rsr\yfoye.bat
  • %User Startup%\fgf.vbs

Step 3

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