SentinelOne Bypass Enables Ransomware

Summary

Researchers discovered a new “Bring Your Own Installer” technique that allows hackers to bypass SentinelOne EDR, leaving systems vulnerable to ransomware like Babuk. This method exploits a gap in the agent upgrade process. SentinelOne has issued mitigation steps, urging customers to enable “Online Authorization.”

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** Main Story**

So, there’s a new ransomware threat on the radar, and it involves bypassing Endpoint Detection and Response (EDR) solutions – specifically, SentinelOne. EDRs, as you know, are a pretty critical line of defense against ransomware these days.

But, hold on to your hats, because researchers over at Aon’s Stroz Friedberg Incident Response team have uncovered something called the ‘Bring Your Own Installer’ technique. Basically, bad actors are using it to sneak past SentinelOne’s EDR, clearing the way for ransomware deployment. It just goes to show you, the cyber threat landscape never stops evolving, does it?

How ‘Bring Your Own Installer’ Works

This ‘Bring Your Own Installer’ is kinda clever, if you think about it. It’s all about exploiting a hiccup in how SentinelOne updates its agent. Usually, SentinelOne is locked down tight with anti-tamper features, which means you can’t just uninstall it without the right authorization.

However, during an update, the installer needs to temporarily shut down existing processes before firing up the new version. And this is where it gets interesting. Attackers are initiating a legitimate SentinelOne installer, only to abruptly kill it before the new agent gets a chance to fully activate. This leaves the system exposed, like a sitting duck, ready for ransomware.

The Stroz Friedberg team actually stumbled upon this during a real-world incident, seeing attackers use this method to deploy the Babuk ransomware. Pretty scary stuff, huh?

SentinelOne’s Response: Locking the Door

The good news is, SentinelOne didn’t waste any time. Back in January 2025, they issued guidance to their customers on how to mitigate this risk. The main recommendation? Enable ‘Online Authorization.’ This setting means any local upgrades, downgrades, or uninstalls of the agent need approval from the SentinelOne management console.

It’s an extra layer of security that effectively slams the door on the ‘Bring Your Own Installer’ technique. Moreover, SentinelOne shared the details of this bypass with other EDR vendors. Always good to see collaboration in the security community, right?

Ransomware: Still a Major Pain

Ransomware, unfortunately, isn’t going anywhere anytime soon. It’s still a major threat for both individuals and companies. You know the drill: attackers encrypt your data and hold it hostage until you pay up. And the consequences can be devastating – financial losses, business disruptions, you name it. I remember a friend telling me how their company almost went bankrupt after a ransomware attack.

Also, it’s not just about encryption anymore. Now we’re seeing ‘double extortion,’ where attackers steal your data and threaten to leak it if you don’t pay. Plus, Ransomware-as-a-Service (RaaS) has made it easier than ever for aspiring cybercriminals to get in on the action.

Defending Against Ransomware: Building a Strong Defense

Okay, so while the ‘Bring Your Own Installer’ thing is specific to SentinelOne, ransomware defense, in general, requires a broader approach. It’s all about building layers of security.

Here’s what I’d recommend:

• Keep Software Updated: This sounds obvious, but you’d be surprised how many organizations fall behind on patching. Regularly update your software to close those security holes.
• Enable Multi-Factor Authentication (MFA): I can’t stress this enough. MFA is an extra layer of protection that makes it way harder for attackers to break in, even if they get their hands on your credentials. Use it wherever you can.
• Regular Backups: Offline, encrypted backups are your lifeline in a ransomware attack. Test them regularly to ensure that, when the worst happens, you can bounce back.
• Security Awareness Training: Phishing emails are still a major attack vector. Teach your employees to spot them and report suspicious activity. It’s an investment that pays off.
• Incident Response Plan: Have a plan in place before an attack happens. Know what to do, who to contact, and how to recover. Time is of the essence in these situations.

In conclusion, the ‘Bring Your Own Installer’ is another wake up call. We all need to stay informed, adapt to new threats, and keep our defenses strong. Cybersecurity is never ‘done,’ and you have to keep on top of it if you don’t want to be tomorrow’s headline.