Defending Against Direct Authentication Attacks in Microsoft Office 365

Whilst conducting security testing and assurance activities, I went looking to show logon events in Office 365. My first query was on IdentityEvents, this led to a view of a multi month attack by a threat actor/s against a tenent, followed by exploring the rabbit hole of logs and computer systems. This blog summarises some of the methods and findings when considering threat hunting and authentication defences for Office 365. (bear with me I am tired so this might need a bit of a tune up later!)

Leadership

The Cyber Acid Test

I’ve been working with all kinds of different organisations over the years, and I keep running into similar scenarios. The current state of the majority of organisations security postures are simply (as a broad-brush statement) far riskier than they need to be.

Conversely there are a range of common challenges I find in almost every org:

Leadership

Password Managers in a Post LastPass breach World

Can you lose maybe 25 million peoples vaults and still claim to be a secure secret management company? Does that even fly? Does it matter that you lose all the metadata (IP access logs), URLs and vast amounts of other metdata but don’t worry ~5 fields are encrypted so as long as your master password is never cracked… yawn…

Setting an Example

Threat Intel

LastPass Breach – The danger of metadata

When an organisation suffers a data breach it’s usually bad. When an organisation that stores 25 million people’s passwords that’s really bad.

There are multiple risks here at play.

Firstly, when we give people our data, it’s our risk and our choice. I’m ok with that, I chose to give lastPass my data.

My vault data might be gone, but I have a strong master password, how we interpreted the theft of the basically cryptographic materials is a bit like when we full disk encrypt a drive.

If you lose a laptop that’s got FDE do you report this as a data loss to the ICO? Or do you say, it’s encrypted so actually I haven’t lost the data per say, I’ve just lost a random (ish) bunch of 0s an 1s so I don’t count that as an incident? I’m not here to be judge or jury.

Defence

Planning to defend and respond to cyber threats

Everyone has a plan until they are cyber punched in the face! Or something like that!

People seem to have this misconception that you need to “do a pentest” or some other project based activity to do “security testing” or response planning.

Let’s be real here, you really don’t. But what you do need is a few things:

Authorisation
Time
Some ideas for cyber incidents to plan for

Guides

Cyber Essentials for Ubuntu Servers

I thought about doing a step by step bash script or CLI walkthrough but decided to go with the high levels steps. If we wanted to ensure our Linux servers are configured in alignment with Cyber Essentials what are the main areas we need to consider? For this I’m using Ubuntu Server as a base, I’ve not gone through every line in the standard but these should be in line with the 5 areas and fit within the Cyber Essentials theme. As always there are many ways to skin a cat! (don’t skin cats they are frens!). Anyway hope this is useful.

Guides

Phishing (Cred harvester) Response

Incident Response Playbook (High Level)

Having a plan for how you will respond to common incidents is key. It’s a good idea to have procedural level “playbooks” (we used to just call these procedures, maybe I’m old!) but let’s get taktic00l and call them:

Playbooks/Runbooks/Aide-mémoire etc.

That aside (words are fun right!) they key part here is to identify the people, roles and responsibilities and the systems/actions/decisions you will need to take. To start with let’s look at a common incident of Phishing with credential harvesting, this may lead onto business email compromise (BEC) and attempted or successful fraud or downstream supply chain attacks.

Leadership

What is a “Winning Cyber Security Strategy”?

A winning cyber security strategy should have several key components.

First, it should involve a thorough assessment of your organization’s current security posture, including identifying any potential vulnerabilities or weaknesses. This assessment should be ongoing, with regular updates to ensure that your security measures are keeping pace with the evolving threat landscape.

Education

Vulnerability Prioritisation

I’ve got 99 vulnerabilities but log4j ain’t one!

Most organisations have hundreds to thousands of vulnerabilities. They range across the spectrum from:

CRITICAL
HIGH
MEDIUM
LOW
INFORMATIONAL

The challenge comes in trying to determine how to prioritise. Which ways could we go?

Where do we start?

Guides

Service Security Architecture and Assurance

Have you every tried to understand the risk level of a service? Ever wanted to provide assurance to someone that “it’s been well designed, is secure from common threats, likely risk scenarios and is securely operated” etc.? have you ever tried to conduct testing against a service that is relatively unknown? Ever needed to actually do more than throw some packets at the front door? Guess what, I have. Most orgs don’t have a decent level of documentation on service architecture and security controls. And as the NSA nicely put, the way they get into networks is to know them better than you do! So in my travels I see lots of different orgs and largely there’s one common similarity, most of them aren’t well documented (docs are boring right!) and if we then make another huge sweeping generalisation, about 90% of orgs have security postures you wouldn’t want to have to defend as a blue teamer, but you might fancy if you were a nation state actor or cyber criminal!