Analysis by: Pearl Charlaine Espejo
ALIASES:

PUP.Optional.DNSUnlocker (Malwarebytes); Trojan.Adware.DNSUnlocker.1 (Arcabit); not-a-virus:HEUR:AdWare.MSIL.DNSUnlocker.gen (Kaspersky)

 PLATFORM:

Windows

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

  • Threat Type: Potentially Unwanted Application

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

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

This potentially unwanted application arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites. It may be manually installed by a user.

It connects to certain websites to send and receive information. It gathers information and reports it to its servers.

  TECHNICAL DETAILS

File Size: 881,276 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 19 Apr 2016
Payload: Connects to URLs/IPs

Arrival Details

This potentially unwanted application arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It may be manually installed by a user.

Installation

This potentially unwanted application adds the following folders:

  • %User Temp%\is-{random characters}.tmp
  • %Program Files%\DNS Unlocker

(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.. %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)

It drops the following files:

  • %User Temp%\is-{random characters}.tmp\{malware filename}.tmp
  • %User Temp%\is-{random characters}.tmp\_isetup\_shfoldr.dll
  • %User Temp%\is-{random characters}.tmp\ConsoleApplication1.dll
  • %User Temp%\is-{random characters}.tmp\config_tmp.ini
  • %Program Files%\DNS Unlocker\is-{random characters}.tmp
  • %Program Files%\DNS Unlocker\unins000.dat
  • %Program Files%\DNS Unlocker\unins000.exe
  • %Program Files%\DNS Unlocker\ConsoleApplication1.dll
  • %Program Files%\DNS Unlocker\dnslockington.exe - detected as PUA_DNSUNLOCKER.GA
  • %Program Files%\DNS Unlocker\ZonaTools.XPlorerBar.dll
  • %Program Files%\DNS Unlocker\Microsoft.Win32.TaskScheduler.dll
  • %Program Files%\DNS Unlocker\config.ini
  • %Program Files%\DNS Unlocker\Info.rtf
  • %Program Files%\DNS Unlocker\License.rtf
  • %Program Files%\DNS Unlocker\DNSLOCKINGTON.cer
  • %Program Files%\DNS Unlocker\LogoBlack.ico
  • %Program Files%\DNS Unlocker\LogoGreen.ico
  • %Program Files%\DNS Unlocker\LogoYellow.ico
  • %Program Files%\DNS Unlocker\settings.ini
  • %System%\d3d9caps.tmp
  • %System%\d3d9caps.dat

(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.. %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Autostart Technique

This potentially unwanted application drops the following files:

  • %Windows%\Tasks\DNSLOCKINGTON.job (Windows XP and below)
  • %System%\Tasks\DNSLOCKINGTON (Windows Vista and above)

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Other System Modifications

This potentially unwanted application adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\5da059a482fd494db3f252126fbc3d5b

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
{E1527582-8509-4011-B922-29E3FB548882}_is1

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
Microsoft\Windows\CurrentVersion\
Uninstall\{E1527582-8509-4011-B922-29E3FB548882}_is1

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\5da059a482fd494db3f252126fbc3d5b
FX = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\5da059a482fd494db3f252126fbc3d5b
SDP1 = "00001"

HKEY_LOCAL_MACHINE\SOFTWARE\5da059a482fd494db3f252126fbc3d5b
SDP2 = "00001"

HKEY_LOCAL_MACHINE\SOFTWARE\5da059a482fd494db3f252126fbc3d5b
UID = "{UID}"

HKEY_LOCAL_MACHINE\SOFTWARE\5da059a482fd494db3f252126fbc3d5b
DP = "77"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
{E1527582-8509-4011-B922-29E3FB548882}_is1
Inno Setup: App Path = "%Program Files%\DNS Unlocker"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
{E1527582-8509-4011-B922-29E3FB548882}_is1
InstallLocation = "%Program Files%\DNS Unlocker\"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
{E1527582-8509-4011-B922-29E3FB548882}_is1
Inno Setup: Icon Group = "DNS Unlocker"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
{E1527582-8509-4011-B922-29E3FB548882}_is1
DisplayName = "DNS Unlocker version 1.4"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
{E1527582-8509-4011-B922-29E3FB548882}_is1
UninstallString = "%Program Files%\DNS Unlocker\unins000.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
{E1527582-8509-4011-B922-29E3FB548882}_is1
QuietUninstallString = ""%Program Files%\DNS Unlocker\unins000.exe" /SILENT"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
{E1527582-8509-4011-B922-29E3FB548882}_is1
NoModify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
{E1527582-8509-4011-B922-29E3FB548882}_is1
NoRepair = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
{E1527582-8509-4011-B922-29E3FB548882}_is1
InstallDate = "{Installation Date}"

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
Microsoft\Windows\CurrentVersion\
Uninstall\{E1527582-8509-4011-B922-29E3FB548882}_is1
InstallDate = "{Installation Date}"

HKEY_LOCAL_MACHINE\SOFTWARE\5da059a482fd494db3f252126fbc3d5b
status = "1"

Other Details

This potentially unwanted application connects to the following website to send and receive information:

  • http://{BLOCKED}03.{BLOCKED}e76e438794c399ea1ccdb9206b.me/QualityCheck/ni6.php
  • {value}.77.1.{value}.updates.{BLOCKED}ek.tv

It does the following:

  • It displays advertisements in the user's browser.
  • It spoofs domain,hosting it to:
    • 77-1d.{BLOCKED}ocker.com ({BLOCKED}.{BLOCKED}.142.7)
    • 77-2d.{BLOCKED}ocker.com ({BLOCKED}.{BLOCKED}.158.134)

    which causes the display of different advertisements.

It gathers the following information and reports it to its servers:

  • Operating System
  • UID
  • Installation Error code

  SOLUTION

Minimum Scan Engine: 9.800
SSAPI PATTERN File: 1.725.00
SSAPI PATTERN Date: 20 Apr 2016

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_LOCAL_MACHINE\SOFTWARE
    • 5da059a482fd494db3f252126fbc3d5b
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall
    • {E1527582-8509-4011-B922-29E3FB548882}_is1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall
    • {E1527582-8509-4011-B922-29E3FB548882}_is1

Step 5

Search and delete these folders

[ 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.
  • %User Temp%\is-{random characters}.tmp
  • %Program Files%\DNS Unlocker

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.  
  • %Windows%\Tasks\DNSLOCKINGTON.job (Windows XP and below)
  • %System%\Tasks\DNSLOCKINGTON (Windows Vista and above)
  • %System%\d3d9caps.tmp
  • %System%\d3d9caps.dat

Step 7

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