SharePoint’s Zero-Day Breach: What We Can Learn

The goal with any zero-day exploit is simple: stop it before it begins. But that's not always how it plays out.

On a quiet Friday, teams around the world logged off for the weekend, unaware that attackers were logging in.

A critical vulnerability in Microsoft SharePoint was being actively exploited. Hackers bypassed authentication, escalated privileges, and quietly deployed malicious code that gave them full access. It took just seven minutes for some organizations to be compromised.

This wasn’t a simulation. It was CVE-2023-29357; an actual flaw chained with another vulnerability to form the now-infamous ToolShell exploit.

Here’s what we’ve learned: attacks like this may not always be fully preventable, but the damage can be dramatically reduced with the right tools, visibility, and controls in place.

What Actually Happened

Imagine someone cloning a keycard to your building and walking past security completely unnoticed.

That’s essentially what ToolShell did. It tricked SharePoint into believing the attacker was a legitimate admin with no password, no verification. Once inside, attackers installed stealthy web shells that allowed them to return at any time, undetected.

Why Traditional Tools Missed It

• The exploit was brand new, no known attack signatures
• It targeted on-prem SharePoint servers, often overlooked in modern monitoring
• Many organizations hadn’t patched yet, creating a window of exposure

In short: most defenses never saw it coming.

What Security Teams Should Do Now

Even if you weren’t affected, this is a clear signal to strengthen your defenses:

✔️ Apply Microsoft’s June 2023 patch and all follow-ups
✔️ Monitor internal behavior—not just perimeter activity
✔️ Enforce stricter token validation and session controls
✔️ Deploy LockThreat in monitor mode to gain visibility, then enable full protection

How Tools Like LockThreat Can Help

While no system can guarantee zero-day immunity, LockThreat helps organizations reduce exposure, accelerate detection, and respond before damage is done.

LockThreat provides:

• Unified visibility across cloud, on-prem, and hybrid environments
• Real-time threat detection powered by AI and behavioral analytics
• Just-in-time access controls to prevent privilege misuse
• Deception technology to expose attackers without alerting them
• Automated response workflows tied to organizational risk posture
• Context-rich alerts that help teams prioritize and act faster

What took attackers seven minutes to execute could be flagged and neutralized in seconds.

By combining security, risk, and compliance into a single platform, LockThreat empowers organizations to adopt a more resilient, GRC-aligned approach to cybersecurity; without slowing down business.

👉 Learn more at www.lockthreat.ai

‍