WORM_AINSLOT.VTN

July 11, 2015
 ALIASES:

Worm:Win32/Ainslot.A (Microsoft); GenericR-DGX!0AADBB7D510F (McAfee); Trojan.Gen.2 (Symantec); HEUR:Trojan.Win32.Generic (Kaspersky); Mal/VBInj-Y (Sophos); Trojan.Win32.Generic!BT (Sunbelt); ERROR (AVG)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This worm 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:

667,648 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

11 Jul 2015

Arrival Details

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

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
CURRENTVERSION/RUN/SECURITY = "%User Profile%\Application Data\9WF74BGFLC.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
CURRENTVERSION/RUN/SECURITY = "%User Profile%\Application Data\9WF74BGFLC.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{EBFE3BD6-2F36-4BFD-A69A-1CAAAE3AF2BD}
StubPath = "%User Profile%\Application Data\9WF74BGFLC.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Active Setup\Installed Components\{EBFE3BD6-2F36-4BFD-A69A-1CAAAE3AF2BD}
StubPath = "%User Profile%\Application Data\9WF74BGFLC.exe"

Other System Modifications

This worm adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\run

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{EBFE3BD6-2F36-4BFD-A69A-1CAAAE3AF2BD}

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Active Setup\Installed Components\{EBFE3BD6-2F36-4BFD-A69A-1CAAAE3AF2BD}

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
SrvID\ID

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
INSTALL\DATE

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\run
CURRENTVERSION/RUN/SECURITY = "%User Profile%\Application Data\9WF74BGFLC.exe"

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
SrvID\ID
HDSBLFPKXI = "bots"

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
INSTALL\DATE
HDSBLFPKXI = "June 2, 2015"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
DoNotAllowExceptions = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%System Root%\\{malware file name}.exe = "{random characters}"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%User Profile%\Application Data\9WF74BGFLC.exe = "{random characters}"

Other Details

This worm connects to the following possibly malicious URL:

  • {BLOCKED}7.48.248

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.750

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\policies\Explorer
    • run
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components
    • {EBFE3BD6-2F36-4BFD-A69A-1CAAAE3AF2BD}
  • In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Active Setup\Installed Components
    • {EBFE3BD6-2F36-4BFD-A69A-1CAAAE3AF2BD}
  • In HKEY_CURRENT_USER\Software\VB and VBA Program Settings\SrvID
    • ID
  • In HKEY_CURRENT_USER\Software\VB and VBA Program Settings\INSTALL
    • DATE

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
    • CURRENTVERSION/RUN/SECURITY = "%User Profile%\Application Data\9WF74BGFLC.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • CURRENTVERSION/RUN/SECURITY = "%User Profile%\Application Data\9WF74BGFLC.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{EBFE3BD6-2F36-4BFD-A69A-1CAAAE3AF2BD}
    • StubPath = "%User Profile%\Application Data\9WF74BGFLC.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Active Setup\Installed Components\{EBFE3BD6-2F36-4BFD-A69A-1CAAAE3AF2BD}
    • StubPath = "%User Profile%\Application Data\9WF74BGFLC.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\run
    • CURRENTVERSION/RUN/SECURITY = "%User Profile%\Application Data\9WF74BGFLC.exe"
  • In HKEY_CURRENT_USER\Software\VB and VBA Program Settings\SrvID\ID
    • HDSBLFPKXI = "bots"
  • In HKEY_CURRENT_USER\Software\VB and VBA Program Settings\INSTALL\DATE
    • HDSBLFPKXI = "June 2, 2015"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
    • DoNotAllowExceptions = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %System Root%\{malware file name}.exe = "{random characters}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %User Profile%\Application Data\9WF74BGFLC.exe = "{random characters}"

Step 5

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