Analysis by: Francis Xavier Antazo

ALIASES:

Worm:Win32/Conficker.B (MICROSOFT), Net-Worm.Win32.Kido.ih (KASPERSKY), I-Worm/Generic.CKH (AVG)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This worm arrives via removable drives.

It bypasses the Windows firewall. This allows the malware to perform its intended routine without being detected by an installed firewall.

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

  TECHNICAL DETAILS

File Size: 167,324 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 06 Aug 2013

Arrival Details

This worm arrives via removable drives.

Installation

This worm adds the following folders:

  • {removable drive}:\RECYCLER
  • {removable drive}:\RECYCLER\S-5-3-42-2819952290-8240758988-879315005-3665

It drops the following files:

  • {Removable Drive Letter}:/autorun.inf
  • %System%\{random characters}.tmp

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

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

  • {removable drive}:\RECYCLER\S-5-3-42-2819952290-8240758988-879315005-3665\jwgkvsq.vmx

Other System Modifications

This worm adds the following registry keys:

HKLM\System\CurrentControlSet\
Services\{Random characters}

It adds the following registry entries:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\{Random characters}
Start = "3"

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\{Random characters}
ErrorControl = "0"

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\{Random characters}
ImagePath = "\??\%System%\{random characters}.tmp"

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\{Random characters}
DisplayName = "{Random characters}"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\Hidden\
Showall
CheckedValue = "0"

(Note: The default value data of the said registry entry is "1".)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = "2"

(Note: The default value data of the said registry entry is "1".)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
SuperHidden = "0"

(Note: The default value data of the said registry entry is "1".)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\wscsvc
Start = "4"

(Note: The default value data of the said registry entry is "2".)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\wuauserv
Start = "4"

(Note: The default value data of the said registry entry is "2".)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\BITS
Start = "4"

(Note: The default value data of the said registry entry is "3".)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\ERSvc
Start = "4"

(Note: The default value data of the said registry entry is "2".)

It modifies the following registry entries to disable the Windows Firewall settings:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
{random numbers}:TCP = "{random numbers}:TCP:*:Enabled:{random characters}"

Propagation

This worm drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

Other Details

This worm connects to the following URL(s) to get the affected system's IP address:

  • www.getmyip.org
  • www.whatismyip.org
  • www.whatsmyipaddress.com
  • checkip.dyndns.org

  SOLUTION

Minimum Scan Engine: 9.700
FIRST VSAPI PATTERN FILE: 10.404.04
VSAPI OPR PATTERN File: 10.405.00

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

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.
  • {Removable Drive Letter}:/autorun.inf
  • %System%\{random characters}.tmp

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\System\CurrentControlSet
    \Services
    • {Random characters}

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_LOCAL_MACHINE\System\CurrentControlSet
    \Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
    • {random numbers}
      :TCP = "{random numbers}
      :TCP:*:Enabled:{random characters}"

Step 6

Restore this modified 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\Explorer\Advanced\Folder\Hidden\Showall
    • From: CheckedValue = "0"
      To: CheckedValue = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: Hidden = "2"
      To: Hidden = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: DontPrettyPath = "0"
      To: DontPrettyPath = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: HideIcons = "0"
      To: HideIcons = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: SuperHidden = "0"
      To: SuperHidden = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet
    \Services\wscsvc
    • From: Start = "4"
      To: Start = "2"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet
    \Services\wuauserv
    • From: Start = "4"
      To: Start = "2"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet
    \Services\BITS
    • From: Start = "4"
      To: Start = "3"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet
    \Services\ERSvc
    • From: Start = "4"
      To: Start = "2"

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.
  • {removable drive}:\RECYCLER

Step 8

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