Analysis by: Nikko Tamana
 Modified by: RonJay Kristoffer Caragay
ALIASES:

Mal/Conficker-A (Sophos), Worm/Downadup (AVG), W32/Kido.IH!tr (Fortinet), W32/Conficker!Generic (FProt), Net-Worm.Win32.Kido (Ikarus), Net-Worm.Win32.Kido.ih (Kaspersky), Worm:Win32/Conficker.B (Microsoft), Win32/Conficker.X worm (NOD32), W32.Downadup.B (Norton), W32/Conficker.C.worm (Panda),

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

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

It requires its main component to successfully perform its intended routine.

  TECHNICAL DETAILS

File Size: 157,577 bytes
File Type: DLL
Memory Resident: Yes
Initial Samples Received Date: 30 Aug 2013

Arrival Details

This worm arrives via removable drives.

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

Other System Modifications

This worm adds the following registry entries as part of its installation routine:

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

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\BITS
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.)

Propagation

This worm creates the following folders in all removable drives:

  • {Removable Drive}:\RECYCLER

It 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 requires its main component to successfully perform its intended routine.

NOTES:

During analysis, content of AUTORUN.INF is blank.

  SOLUTION

Minimum Scan Engine: 9.700
FIRST VSAPI PATTERN FILE: 10.374.04
FIRST VSAPI PATTERN DATE: 30 Aug 2013
VSAPI OPR PATTERN File: 10.375.00
VSAPI OPR PATTERN Date: 31 Aug 2013

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

Scan your computer with your Trend Micro product and note files detected as WORM_DOWNAD.FX

Step 4

Restart in Safe Mode

[ Learn More ]

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}:\RECYCLER

Step 6

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}:TCP = "{random}:TCP:*:Enabled:{random letters}"

Step 7

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: SuperHidden = "0"
      To: SuperHidden = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\BITS
    • 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 8

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