Analysis by: Mar Philip Elaurza
ALIASES:

Backdoor.Locobad.B (Symantec), Trojan:Win32/Dorv.A (Microsoft), Backdoor.Win32.PcClient.fvmq (Kaspersky),

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

This backdoor may be dropped by other malware.

It runs certain commands that it receives remotely from a malicious user. Doing this puts the affected computer and information found on the computer at greater risk. However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 15,360 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 28 Sep 2015
Payload: Compromises system security, Connects to URLs/IPs

Arrival Details

This backdoor may be dropped by the following malware:

Installation

This backdoor drops the following file(s)/component(s):

  • %User Startup%\Update.bat - creates the Auto-run registry entry

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

It creates the following folders:

  • %Temp%\logs

(Note: %Temp% is the Windows temporary folder, where it usually is C:\Windows\Temp on all Windows operating system versions.)

Autostart Technique

This backdoor adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
Load = %Temp%\sqlserver.exe

Backdoor Routine

This backdoor executes the following command(s) from a remote malicious user:

  • Create/Update INI files with the following filenames:
    • %Temp%\usrer_{number}.ini
    • %Temp%\usr32_{number}.ini
    • %Temp%\sos32_{number}.ini
  • Create/Delete log file
    • %Temp%\logs\DownFileTree.log
  • Execute arbitrary files
  • Sleep
  • Terminate
  • Delete its copy

(Note: %Temp% is the Windows temporary folder, where it usually is C:\Windows\Temp on all Windows operating system versions.)

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

  • http://{BLOCKED}d.{BLOCKED}s.biz:80/result?hl=en&meta={data}
  • http://{BLOCKED}ter.{BLOCKED}s.info:80/result?hl=en&meta={data}

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

  • Computer Name
  • User Name
  • OS Version Information
  • CPU Information

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

  SOLUTION

Minimum Scan Engine: 9.700
FIRST VSAPI PATTERN FILE: 11.580.09
FIRST VSAPI PATTERN DATE: 03 Apr 2015
VSAPI OPR PATTERN File: 11.581.00
VSAPI OPR PATTERN Date: 03 Apr 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

Identify and terminate files detected as BKDR_GIPPERS.A

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

Remove malware/grayware files that dropped/downloaded BKDR_GIPPERS.A. (Note: Please skip this step if the threats listed below have already been removed.)

Step 5

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\Windows NT\CurrentVersion\Windows
    • Load = %Temp%\sqlserver.exe

Step 6

Search and delete these components

[ Learn More ]
There may be some components 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.
  • %User Startup%\Update.bat

Step 7

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %Temp%\logs

Step 8

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