WORM_DOWNAD.PICJ

 Analysis by: Wilbert Vidal

 ALIASES:

Net-Worm.Win32.Kido.ih (Kaspersky); W32.Downadup.B (Norton); Worm:Win32/Conficker.B (Microsoft); Worm.Generic.70821 (Bitdefender); W32/Conficker.B!worm (Fortinet)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Propagates via flashdrives, Dropped by other malware, Downloaded from the Internet

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 modifies registry entries to disable various system services. This action prevents most of the system functions to be used. It deletes registry entries related to antivirus programs. Doing this allows this malware to execute its routines without being detected by installed antivirus programs.

It drops copies of itself into network drives. 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:

167,050 bytes

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

05 Feb 2011

Payload:

Drops files, Modifies system registry, Connects to URLs/IPs

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.

Installation

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

  • %System%\{random file name}.dll
  • %Program Files%\Internet Explorer\{random file name}.dll
  • %Program Files%\Movie Maker\{random file name}.dll
  • %Application Data%\{random file name}.dll
  • %User Temp%\{random file name}.dll

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.. %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

It creates the following folders with attributes set to System and Hidden to prevent users from discovering and removing its components:

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

Autostart Technique

This Worm registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random characters}
DisplayName = "{random}"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random characters}
Type = 32

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random characters}
Start = 2

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random characters}
ErrorControl = 0

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random characters}
ImagePath = "%System Root%\system32\svchost.exe -k netsvcs"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random characters}
ObjectName = "Local System"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random characters}
Description = "{long sentences}"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random characters}\Parameters
ServiceDll = "%System%\{random malware name}.dll" or %Program Files%\Internet Explorer\{random file name}.dll or %Program Files%\Movie Maker\{random file name}.dll or %Application Data%\{random file name}.dll or %User Temp%\{random file name}.dll

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random characters} = rundll32.exe "%System%\{random malware name}.dll",hxyvra

Other System Modifications

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Applets
(Default) = "0"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Tcpip\Parameters
TcpNumConnections = "0x00FFFFFE" or "0xA"

(Note: The default value data of the said registry entry is {System Default}.)

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\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SvcHost
netsvcs = "{original value}, {random service name created by the malware}"

It modifies registry entries to disable the following system services:

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

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

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

It modifies the following registry entries to hide files with Hidden attributes:

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.)

It deletes the following registry entries related to antivirus and security applications:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
Windows Defender = "{value}"

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\explorer\
ShellServiceObjects\{FD6905CE-952F-41F1-9A6F-135D9C6622CC}

Propagation

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

  • {drive letter}:\RECYCLER\{SID}\jwgkvsq.vmx

It drops copies of itself into network drives.

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

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

It connects to the following time servers to determine the current date:

  • http://www.w3.org
  • http://www.ask.com
  • http://www.yahoo.com
  • http://www.google.com
  • http://www.baidu.com

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.814.07

FIRST VSAPI PATTERN DATE:

30 Nov 2017

VSAPI OPR PATTERN File:

13.815.00

VSAPI OPR PATTERN Date:

01 Dec 2017

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

Restart in Safe Mode

[ Learn More ]

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\SOFTWARE\Microsoft\Windows\CurrentVersion\Applets
    • (Default) = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • {random characters} = rundll32.exe "%System%\{random malware name}.dll",hxyvra

Step 6

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
    • From: TcpNumConnections = "0x00FFFFFE" or "0xA"
      To: TcpNumConnections = {System Default}
  • 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\SOFTWARE\Microsoft\Windows\CurrentVersion\explorer\Advanced\Folder\Hidden\SHOWALL
    • From: CheckedValue = "0"
      To: CheckedValue = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SvcHost
    • From: netsvcs = "{original value}, {random service name created by the malware}"
      To: netsvcs = "{original value}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WinDefend
    • 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\WerSvc
    • 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\BITS
    • 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 letter}:\RECYCLER

Step 8

Search and delete these files

[ 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 file name}.dll
  • %Program Files%\Internet Explorer\{random file name}.dll
  • %Program Files%\Movie Maker\{random file name}.dll
  • %Application Data%\{random file name}.dll
  • %User Temp%\{random file name}.dll

Step 9

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