Microsoft March 2024 patches domain controller lsass memory leak

Microsoft has released an out of band update to fix the memory leak issues with the lsass process on Domain Controllers after applying the March 2024 cumulative update. Microsoft strongly recommends that the latest servicing stack updates are installed before applying the out of band patch.

This out of band patch is a cumulative update and can be installed in place of the normal March cumulative update that is published on Windows Update / local WSUS server. If you want this patch in WSUS you will have to side load it yourself.

We have confirmed in our testing environment that the lsass memory process was starting to creep up. We removed the March cumulative update and applied the out of band patch in our test environment and so far all seems good.

The below is copied from the Windows Message Center as of today. (Link below)
https://learn.microsoft.com/en-us/windows/release-health/windows-message-center#3143

Out-of-band updates to address a Windows Server domain controller issue

Updated March 25, 2024

Microsoft has identified an issue that affects Windows Server domain controllers (DCs), and has expedited a resolution that can be applied to affected devices. Out-of-band (OOB) updates have been released for some versions of Windows today, March 22, 2024, to addresses this issue related to a memory leak in the Local Security Authority Subsystem Service (LSASS). This occurs when on-premises and cloud-based Active Directory domain controllers service Kerberos authentication requests.

This issue is not expected to impact Home users, as it is only observed in some versions of Windows Server. Domain controllers are not commonly used in personal and home devices.

Updates are available on the Microsoft Update Catalog only. These are cumulative updates, so you do not need to apply any previous update before installing them, and they supersede all previous updates for affected versions. If your organization uses the affected server platforms as DCs and you haven’t deployed the March 2024 security updated yet, we recommend you apply this OOB update instead. For more information and instructions on how to install this update on your device, consult the below resources for your version of Windows:

As of March 25, 2024, all affected versions have been addressed via the updates above.

Turning Off Passwordless Authentication – Microsoft Authenticator App

This might be an unpopular take but I very much dislike the way Microsoft uses its Authenticator app for personal accounts. Seriously, it sucks.

If you have a personal account with Microsoft and turn off passwordless authentication in your account but enable two factor with the Microsoft Authenticator, it turns on passwordless authentication in the app for you and you can’t disable it. (Queue up the MFA fatigue).

The way to fix this is to setup another authenticator that’s not the Microsoft one. Save your sanity and stop being MFA bombed by threat actors trying to break into your accounts.

Do better Microsoft, do better.

Setting up Cluster Aware Updates on Server 2016 with Pre-staged Object

Right-Click your cluster in Server Manager and select “Cluster-Aware Updating”

On the Cluster-Aware Updating Dialog Box, click “Configure Cluster Self-Updating Options” on the right-hand side.

Click “Next” when the wizard opens

On the next screen, make sure you go pre-stage a computer object and put that info here.
Note: After creating the new computer object, do the following:
1. Edit the Security Properties of that computer object and give the cluster computer object FULL CONTROL of the new computer object you just created.
2. Protect the new computer object from accidental deletion
3. Disable the newly created computer object

Choose the schedule

Review Advanced Options

Leave defaults on the next screen

Review before clicking Apply:

Wait for the Cluster Role to complete

Successfully configured!

Protecting vCenter 7 with MFA using Duo and ADFS

This blog is not going to go through the details get the initial ADFS setup. I’m using ADFS on Server 2019 for this demo though. Bring up a Windows Server 2019 and install the ADFS role. This will require a valid SSL certificate. I did not bring up a web proxy as this ADFS server’s only function is to serve authentication for vCenter so we can put DUO behind ADFS.

Add ADFS Certificate(s) Chain to vCenter:

Add the Root & Intermediate CA certificates to vcenter. This can be done under Administration in vCenter at the bottom under Certificates click “Certificate Management”.

Then next to Trusted Root Certificates, click Add and Add Root and/or Intermediate CA certificates here. I added just regular .CRT files that you could open with notepad and show the certificate text.

While here in vCenter Administration, navigate to Single Sign On -> Configuration

Over on the right hand side click on the “i” next to “Change Identity Provider”

Make note of these Redirect URIs you will need them when you configure ADFS.

Configure ADFS for vCenter:

You should now have a brand new install of ADFS with the most basic things configured to make it happy including your SSL certificate. Launch the ADFS Management tool and right click “Application Groups” and click “Add Application Group”.

In the wizard that appears, give your Application a Name and Description that means something to you and select “Server application accessing a web API” and click “Next”.

Make note of the Client Identifier. This will be needed later in vCenter configuration. Also input the two redirect URLs you noted earlier in vCenter. Click “Next”.

Check the box to Generate a shared secret and copy this down as it will be needed later in vCenter configuration. Click “Next”.

Input the Client Identifier from earlier in this wizard in the Identifier box and click “Add” and then Click “Next”.

On the next screen for now click “Permit everyone” we can revisit this later after everything is setup. Click “Next”.

On the next screen make sure “openid” and “allatclaims” are both checked, you will probably have to check “allatclaims”. Click “Next”.

Review and make sure everything looks good. Your Server Application Identifier, and Web API Identifiers should be the same GUID. Click “Next”, and “Close”.

We now need to configure the claims before we can attempt to configure vCenter and attempt a login.

Right-Click the newly created Application Group and select “Properties”

Select the item under Web API and click “Edit”

Click on Issuance Transform Rules. Here we will create three rules. Click Add Rule three times and make your rules look like the following:
(Note: All Rules will use the default “Send LDAP Attributes as Claims”)

Group Rule:

LDAP Attribute: Token-Groups Qualified by Long Domain Name

Outgoing Claim Type: Group

Subject Rule:

LDAP Attribute: User-Principal-Name

Outgoing Claim Type: Name ID

UPN Rule:

LDAP Attribute: User-Principal-Name

Outgoing Claim Type: UPN

Click “OK” to close the dialog box after all three rules have been configured. Click “OK” again to close the Authentication Properties box.

Before we switch over to vCenter configuration we need to snag one more thing from our ADFS server, it is our OpenID Address. To obtain this launch a PowerShell window as Administrator on your ADFS server and type in the following:

Get-AdfsEndpoint | Select FullUrl | Select-String openid-configuration

You should receive something like the following (save this URL you will need it for vCenter configuration):

vCenter ADFS Configuration:

We are now ready to setup the Identity Provider in vCenter. Navigate back to Administration -> Single Sign On -> Configuration.

This time click the “Change Identity Provider” link instead of the “i” next to it.

Click “Microsoft ADFS” and click “Next”.

On the next screen, you want to copy the Client Identifier and Shared Secret from ADFS that you set aside during setup. The OpenID address also that we just snagged from ADFS.

On the next page fill out the base DN for Users and Groups, I’m using the root because this is just a lab setup. I’m using a service account (only requires read access to AD), and I’m only using ldap:// again because this is a home lab. If you are setting this up in Production make sure you are using ldaps://.

Click “Next”, review and click “Finish”.

You should now be able to add an Admin group in vCenter from your Active Directory source. At this point you should be able to logout and log back in to test out authentication to ADFS.

———–YOU SHOULD NOW HAVE vCENTER & ADFS SETUP————

Proceed forward for the DUO configuration and setup.

Login to your DUO Administration Portal and Click “Applications” and then “Protect and Application” and then locate the entry for “Microsoft ADFS” and click “Protect”

Take note of your “Client ID”, “Client Secret” and “API Hostname”. You will need this information to complete setup on your ADFS server.

Download the DUO ADFS Installer Package for ADFS 2016 or later. (https://dl.duosecurity.com/duo-adfs3-latest.msi)

Run the DUO Installer:

If you have an AD FS farm install Duo on the Primary Server first, if you have a SQL farm you may begin with any node. Since this is just a lab I only have the one server.

Launch the Installer. Click “Next”

Enter the Information from the DUO Admin page, or what your Information Security Team will need to provide to you.

Bypass Duo authentication when offline (unchecked) will make sure it “fails closed” and nobody will be able to access resources if Duo is down. This can be changed later in the registry.

By default DUO sends the sAMAccountName, if you want UPN sent, check the box that says “Use UPN username format”.

Click “Next” and Click “Install”

You may then be prompted by DUO to enable the DUO MFA Authentication.

To do this in ADFS Management Open up Service -> Right-Click “Authentication Methods” and click “Edit Multi-factor Authentication Methods”.

Check the box for Duo and click “OK”

At this point you should still be able to login to ADFS and MFA will NOT be working.

Configure ADFS for MFA:

Go back to your Application Groups, and Right-Click your Application Group and click “Properties”

Click Web API and click “Edit”

Go to Access Control Policy and click “Permit Everyone and require MFA”

Test Your Setup and Troubleshoot as needed!

Free Cloudflare WAF Initial Review

After messing with using .htaccess files to lock down my blog I decided to try Cloudflare’s free offering for a simple WAF to protect my blog as well as get some more detail as far as who is talking to it.

I’m still working on configuring Cloudflare and I may have more to say after I get more time to get used to the interface and make some more tweaks.

One of the most important things I wanted to do was be able to lockdown /wp-login.php, /wp-admin, and /xmlrpc.php like I was doing with .htaccess.

I was able to get the same lock down functionality done relatively quickly, using the WAF security rules.

Over on the left-hand side if you navigate to Security -> WAF

I used their template for Zone lockdown, and blocked access to those things from everyone except my IP, which can obviously be edited later if it ever changes or I’m out traveling and want to update my blog.

Of course another lesson learned is you can’t use your domain anymore to SSH to your server. Cloudflare will not allow it. So I created a SSH sub-domain on my domainname in Cloudflare and set it to DNS only.

You might say this defeats the whole purpose of cloudflare because now somebody knows your IP address, and to a certain extent that is true. However, I have apache configured so if someone tries to browse by IP address they get a 403 from .htaccess in a different web directory.

WordPress Security Tweaks (.htaccess)

As I get more familiar with WordPress I keep making tweaks to my blog to lock things down more. I thought I would share some of the things I have put in place to help others.

One of the first things I did was monitor the Apache access.log (/var/log/apache2/access.log) to see what kind of traffic was hitting my site.

Here is a summary of web calls I found interesting:

  • /xmlrpc.php
  • /wp-admin
  • /wp-login.php
  • /wp-content

With the REST API on later versions of WordPress the /xmlrpc.php is no longer needed and is therefore a security risk that can allow login attempts to the website. Please read up on it before you disable it if you don’t know what it is.

/wp-admin & /wp-login.php are of course the login page for the site and if we can limit who can access this, this would also drastically increase security

The last one was I was noticing a lot of browsing happening in the /wp-content folder which by default has directory browsing turned on, so anyone can browse any of the files there. We can add a little more security here by turning off directory browsing.

Edit Root .htaccess file

Open up your .htaccess file in the root directory of your WordPress web site. This will already have some WordPress specific items in it.

This is what I added onto the file:

...
</IfModule>
#END WordPress

# Make Sure Hidden Files Are Not Accessible (dot files)
RedirectMatch 403 /\..*$

# Block WordPress xmlrpc.php requests
<Files ~ "xmlrpc\.php">
        <RequireAll>
                Require all denied
        </RequireAll>
</Files>

# Block WordPress login page requests unless from certain IP
<Files ~ "wp-login\.php">
        <RequireAll>
                Require ip xxx.xxx.xxx.xxx #Put IPs you want to allow here can space separate them
        </RequireAll>
</Files>

#Disable Directory Browsing
Options -Indexes

This makes sense for me because I am the only one accessing the administration of this website so it does not need to be open to the world.

The last change I made was I created a .htaccess file in the /wp-admin folder.

/wp-admin .htaccess file

This is what the .htaccess file looks like that I created in the /wp-admin folder

# Block WordPress Requests to /wp-admin
<Limit GET POST PUT>
        <RequireAll>
                 Require ip xxx.xxx.xxx.xxx #Replace with your IP
        </RequireAll>
</Limit>

These security settings make sense for me as this is a simple blog with one user but they may not make sense for you. I also run no plugins on the site to lower my risk threshold.

Of course the one downside to doing things this way, is if my IP at home changes or I’m out traveling I’ll have to SSH in to the server to allow myself to login, but I’m ok with this. As far as SSH goes I would also strongly suggest key authentication instead of username/password.

Bringing up OWASP JuiceShop on Kali Linux

I attended a talk last night regarding web application security and the speaker was presenting about OWASP JuiceShop which I had played with very little in the past. I have since started to bring this application back up to play with locally.

I will be writing up tutorials as I go through them.

To “install” OWASP JuiceShop on Kali Linux using docker do the following:

Install Docker: sudo apt install docker.io

Run: sudo docker pull bkimminich/juice-shop

Run: sudo docker run -d -p 3000:3000 bkimminich/juice-shop

Quick Docker Commands To View/Stop Containers:

To view what docker containers are running: sudo docker container ls

To stop a docker container: sudo docker stop 5698ef8694e5 (Using the ContainerID from above, use your own Container ID here)

Performing another sudo docker container ls shows that there are now no containers running.

Installing Django on Ubuntu Desktop 22.04 LTS

First run sudo apt update and sudo apt upgrade to get all packages and versions up to the latest, including most importantly python.

You can check what version of python you are running with: python – -version or python3 – -version

Install python3-pip: sudo apt install python3-pip

Once that is installed, install pipenv: pip3 install pipenv

You may receive a note that pipenv is not in your path, so update your .bashrc file in your home directory and add this to the end:

export PATH=”/home/<username>/.local/bin:$PATH”

Close and re-open your terminal.

You should now be ready to create a directory for your django and activate the virtual environment in that folder by running: pipenv shell

You can now install django: pipenv install django

Replacing SSL Certificates with Built-In Windows Server OS Certificate Binding

If you have an application running on your Windows Server OS that is not using IIS as a front-end, it may be relying on the built-in Certificate Binding in Windows.

In order to check the certificate bindings you can run:

netsh http show sslcert

If you need to update one of the certificates listed here you can run:

netsh http update sslcert ipport=0.0.0.0:443 certhash=certhash appid=”{appid}”

Note: ipport, appid will be given to you with the first command to look at the certs, use the values of the current cert that is/was working. Make sure the certhash is the new certificate you want to be used here.