ALIASES:

Backdoor:Win32/Optixpro.K (Microsoft); BackDoor-RS (McAfee); Backdoor.Optix (Symantec); Trojan-Downloader.Win32.Agent.te, Backdoor.Win32.Optix.b, Backdoor.Win32.Optix.Pro.m, Backdoor.Win32 (Kaspersky); Backdoor.Optix.Pro.1.3.Dam.2 (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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: 737,395 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 04 Nov 2011

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 copies of itself into the affected system:

  • %System%\msiexec16.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
GLSetIT32 = "%System%\msiexec16.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\RunServices
GLSetIT32 = "%System%\msiexec16.exe"

Other System Modifications

This backdoor adds the following registry keys:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\RunServices

HKEY_CURRENT_USER\Software\Microsoft\
RAS Autodial\Control

HKEY_LOCAL_MACHINE\Software\Microsoft\
RAS Autodial\Control

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\MediaResources\msvideo

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Hardware Profiles\0001\Software\
Microsoft\windows\CurrentVersion\
Internet Settings
EnableAutodial = "{random values}"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Internet Settings
EnableAutodial = "{random values}"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
EnableAutodial = "{random values}"

HKEY_CURRENT_USER\Software\Microsoft\
RAS Autodial\Control
LoginSessionDisable = "{random values}"

HKEY_CURRENT_USER\Software\Microsoft\
RAS Autodial\Control
DisableConnectionQuery = "{random values}"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
RAS AutoDial\Control
LoginSessionDisable = "{random values}"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
RAS AutoDial\Control
DisableConnectionQuery = "{random values}"

Other Details

This backdoor connects to the following possibly malicious URL:

  • https://nexus.{BLOCKED}rt.com/rdr/pprdr.asp
  • https://login.{BLOCKED}e.com/login2.srf

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.200

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

Restart in Safe Mode

[ Learn More ]

Step 3

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\Microsoft\Windows\CurrentVersion
    • RunServices
  • In HKEY_CURRENT_USER\Software\Microsoft\RAS Autodial
    • Control
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\RAS Autodial
    • Control
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\MediaResources
    • msvideo

Step 4

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • GLSetIT32 = "%System%\msiexec16.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices
    • GLSetIT32 = "%System%\msiexec16.exe"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Hardware Profiles\0001\Software\Microsoft\windows\CurrentVersion\Internet Settings
    • EnableAutodial = "{random values}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings
    • EnableAutodial = "{random values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • EnableAutodial = "{random values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\RAS Autodial\Control
    • LoginSessionDisable = "{random values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\RAS Autodial\Control
    • DisableConnectionQuery = "{random values}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\RAS AutoDial\Control
    • LoginSessionDisable = "{random values}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\RAS AutoDial\Control
    • DisableConnectionQuery = "{random values}"

Step 5

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