arrow_back
search
close

WORM_DOWNAD.EY

April 22, 2014
 Analysis by: Adrian Cofreros
 ALIASES:

Worm:Win32/Conficker.B (Microsoft),Net-Worm.Win32.Kido.ih (Kaspersky),W32.Downadup (Symantec)

 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: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This worm arrives via removable drives. It may be dropped by other malware.

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:

161,814 bytes

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

02 Jan 2014

Arrival Details

This worm arrives via removable drives.

It may be dropped by other malware.

Installation

This worm drops the following copies of itself into the affected system:

  • %System%\{random}.dll

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

Other System Modifications

This worm 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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\BITS
Start = "4"

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

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

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

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

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

It creates the following registry entry(ies) to bypass Windows Firewall:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
{random port number}:TCP = "{random port number}:TCP:*:Enabled:{random value}"

Propagation

This worm creates the following folders in all removable drives:

  • {removable drive letter}:\RECYCLER
  • {removable drive letter}:\RECYCLER\{SID}

It drops the following copy(ies) of itself in all removable drives:

  • {removable drive letter}:\RECYCLER\{SID}\{random characters}

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

The said .INF file contains the following strings:

;{garbage characters}
[AUTorUN
;{garbage characters}
AcTION=Open folder to view files
;{garbage characters}
icon=%syStEmrOot%\sySTEM32\sHELL32.Dll ,4
;{garbage characters}
shelLExECUte=RuNdLl32.EXE .\RECYCLER\{SID}\{random characters},{value}
;{garbage characters}

Other Details

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

  • http://www.whatsmyipaddress.com
  • http://checkip.dyndns.org

NOTES:

Upon execution, it opens a window which displays the files under the malware path's root drive to hide its malicious routines from the user.

It also modifies its file attributes to Read-only and Hidden after execution.

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

10.516.02

FIRST VSAPI PATTERN DATE:

02 Jan 2014

VSAPI OPR PATTERN File:

10.517.00

VSAPI OPR PATTERN Date:

03 Jan 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

Restart in Safe Mode

[ Learn More ]

Step 3

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 port number}:TCP = "{random port number}:TCP:*:Enabled:{random value}"

Step 4

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: Hidden = "2"
      To: Hidden = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden\SHOWALL
    • From: CheckedValue = "0"
      To: CheckedValue = 1
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\BITS
    • From: Start = "4"
      To: Start = 2
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\ERSvc
    • From: Start = "4"
      To: Start = 2
  • 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

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.
  • {removable drive letter}:\RECYCLER

Step 6

Search and delete AUTORUN.INF files created by WORM_DOWNAD.EY that contain these strings

[ Learn More ]


;{garbage characters}
[Autorun
;{garbage characters}
AcTION=Open folder to view files
;{garbage characters}
icon=%Systemroot%\sySTEM32\sHELL32.Dll ,4
;{garbage characters}
shelLExECUte=RuNdLl32.EXE .\RECYCLER\{SID}\{random characters},{value}
;{garbage characters}

Step 7

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


Did this description help? Tell us how we did.