Analysis by: Al Victor de Leon
 Modified by: Al Victor de Leon
 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: Yes

  • In the wild: Yes

  OVERVIEW

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

This backdoor was hosted in the compromised Gizmodo Brazil website. It starts out as a fake Adobe Flash Player download.

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

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.

  TECHNICAL DETAILS

File Size: 39,055,497 bytes
Memory Resident: Yes
Initial Samples Received Date: 29 Jul 2014
Payload: Connects to URLs/IPs, Compromises network security, Downloads files

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 files:

  • %User Temp%\{4 random numbers}.tmp
  • %User Temp%\t.reg
  • %Application Data%\temp.txt - This file receives the strings to be appended to addon.exe and to be deleted right after

(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.. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

It drops the following component file(s):

  • %Application Data%\WinNTService.vbs - detected as VBS_PROXY.BEE
  • %All Users Profile%\javau.n - detected as VBS_PROXY.BEE

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.. %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.)

It drops the following copies of itself into the affected system:

  • %All Users Profile%\addon.exe

(Note: %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.)

Other System Modifications

This backdoor adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
EnableLUA = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
ConsentPromptBehaviorAdmin = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
AutoConfigURL = "%All Users Profile%\javau.n"

Backdoor Routine

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

  • http://{BLOCKED}.{BLOCKED}.203.163/rename/00006/c.php?tip=[0][WINXP][][[P]&inf=
  • http://{BLOCKED}.{BLOCKED}.203.163/rename/00003/notify.php
  • http://{BLOCKED}.{BLOCKED}4.com/nmupd.txt

Download Routine

This backdoor connects to the following URL(s) to download its component file(s):

  • http://{BLOCKED}.{BLOCKED}.203.164/ver.vbs - It saves the downloaded file as %Application Data%\WinNtService.vbs
  • http://{BLOCKED}.{BLOCKED}4.com/yes.vbs - copy of %Application Data%\WinNtService.vbs
  • http://{BLOCKED}.{BLOCKED}4.com/windesktop.gif
  • http://{BLOCKED}.{BLOCKED}4.com/pluginchrome.zip - It saves the downloaded file as %Application Data%\Google\Chrome\User Data\Default\pluginchrome.zip - detected as BREX_EUPUDS.GHR

NOTES:

It executes %System%\ping.exe -n 1 g.{BLOCKED}p14.com to check for connection

It may use the following backdoor commands:

  • BBABORT
  • BBALL
  • BBCANCEL
  • BBCLOSE
  • BBHELP
  • BBIGNORE
  • BBNO
  • BBOK
  • BBRETRY
  • BBYES
  • CDROM
  • CLOSEDFOLDER
  • CURRENTFOLDER
  • EXECUTABLE
  • FLOPPY
  • HARD
  • KNOWNFILE
  • NETWORK
  • OPENFOLDER
  • PREVIEWGLYPH
  • RAM
  • UNKNOWNFILE
  • DLGTEMPLATE
  • DVCLAL
  • PACKAGEINFO
  • TFORM1

It appends the legitimate file %User Profile%\Application Data\Mozilla\Firefox\Profiles\{random}\prefs.js:

  • user_pref(network.proxy.autoconfig_url)%All Users Profile%\javau.n)
  • user_pref(network.proxy.type, 2)

Drops and extracts %Application Data%\Google\Chrome\User Data\Default\pluginchrome.zip into folder %Application Data%\Google\Chrome\User Data\Default\Extensions\{random characters} which contains the ff files/components:

  • getPagesSource.js
  • img\flash128.png
  • img\flash48.png
  • img\Thumbs.db
  • manifest.json
  • popup.html
  • popup.js

  SOLUTION

Minimum Scan Engine: 9.700
FIRST VSAPI PATTERN FILE: 10.952.07
FIRST VSAPI PATTERN DATE: 29 Jul 2014
VSAPI OPR PATTERN File: 10.955.00
VSAPI OPR PATTERN Date: 31 Jul 2014

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

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

    • VBS_PROXY.BEE
    • BREX_EUPUDS.GHR

Step 4

Scan your computer with your Trend Micro product and note files detected as BKDR_QULKONWI.GHR

Step 5

Restart in Safe Mode

[ Learn More ]

Step 6

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%\temp.txt
  • %User Temp%\{4 random numbers}.tmp
  • %User Temp%\t.reg
  • %User Temp%\flager

Step 7

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

Step 8

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.

RESTORE
  • Close Registry Editor.

    • Step 9

    Reset Internet security settings

    [ Learn More ]

    Step 10

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

    Step 11

    The following created files/folders/registry keys/registry entries cannot be identified by the user since there are no reference values in the created key. The only way it can be identified is by comparing the present system information with a backup. Note that the said components do not have to be deleted since it won't be harmful to the system.

    • %Application Data%\Google\Chrome\User Data\Default\Extensions\{random characters}

    NOTES:
    Delete the following strings from %User Profile%\Application Data\Mozilla\Firefox\Profiles\{random}\prefs.js:

    • user_pref(network.proxy.autoconfig_url)%All Users Profile%\javau.n)
    • user_pref(network.proxy.type, 2)


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