ALIASES:

Backdoor.Win32.NetWiredRC.aaw (Kaspersky); Troj/AutoIt-AZC (Sophos)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 REPORTED INFECTION:
 SYSTEM IMPACT RATING:
 INFORMATION EXPOSURE:

  • Threat Type: Spyware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This spyware 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: 1,106,432 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 05 Jun 2015

Arrival Details

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

  • %User Profile%\windows\{malware file name}
  • %User Temp%\Microsoft Maintenance\WinData.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %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:

  • %User Profile%\Application Data\Windows
  • %User Temp%\Ind
  • %User Temp%\Microsoft Maintenance

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %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.)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
Microsoft Corporation = "%User Temp%\Ind\boot.lnk,explorer.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
Microsoft Corporation = "%User Temp%\Ind\boot.lnk"

It modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Userinit = "%System%\Userinit.exe,%User Temp%\Microsoft Maintenance\WinData.exe"

(Note: The default value data of the said registry entry is %Windows%\system32\userinit.exe,.)

Other System Modifications

This spyware deletes the following files:

  • %User Startup%\desktop.ini

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
system
EnableLUA = "0"

It deletes the following registry keys:

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run\
OptionalComponents\IMAIL

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run\
OptionalComponents\MAPI

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run\
OptionalComponents\MSFS

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run\
OptionalComponents

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run

Dropping Routine

This spyware drops the following files:

  • %User Temp%\Ind\boot.lnk
  • %User Temp%\run.vbs
  • %System Root%\.Identifier

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

Other Details

This spyware connects to the following possibly malicious URL:

  • {BLOCKED}.4.75

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

Identify and delete files detected as TSPY_KEYLOG.YYLV using either the Startup Disk or Recovery Console

[ 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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
    • Microsoft Corporation = "%User Temp%\Ind\boot.lnk,explorer.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
    • Microsoft Corporation = "%User Temp%\Ind\boot.lnk"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\system
    • EnableLUA = "0"

Step 4

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\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • From: Userinit = "%System%\Userinit.exe,%User Temp%\Microsoft Maintenance\WinData.exe"
      To: Userinit = ""%Windows%\system32\userinit.exe,""

Step 5

Search and delete these components

[ Learn More ]
There may be some components 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.
  • %User Temp%\Ind\boot.lnk
  • %User Temp%\run.vbs
  • %System Root%\.Identifier

Step 6

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.
  • %User Profile%\Application Data\Windows
  • %User Temp%\Ind
  • %User Temp%\Microsoft Maintenance

Step 7

Scan your computer with your Trend Micro product to delete files detected as TSPY_KEYLOG.YYLV. 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.

Step 8

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %User Startup%\desktop.ini

Step 9

Restore these deleted registry keys/values from backup

*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

  • In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion
    • Run
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\OptionalComponents
    • IMAIL
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\OptionalComponents
    • MAPI
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\OptionalComponents
    • MSFS
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • OptionalComponents
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion
    • Run


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