This Week in Security: September 24, 2026

Security researchers recently identified a technique where attackers sideload a malicious package alongside a legitimately signed Microsoft binary to steal OAuth tokens directly from a user's system. There is no phishing email, no fake login page, and no browser involved at all. Because the binary carries a valid Microsoft signature, traditional defenses that trust signed software can miss the malicious activity entirely.

Why this matters for your firm

OAuth tokens are what keep you logged into Microsoft 365, Outlook, and cloud document storage without re-entering your password every time. If a token is stolen, an attacker can access client email, case files, and calendars while looking like a normal, authenticated session, often without tripping the alarms a stolen password would. For a solo practitioner running Microsoft 365 with default settings, this is a quiet, effective way to get inside your firm's most sensitive systems.

Florida Bar Rule 4-1.6 and Recommendation 25-1

Under Rule 4-1.6, attorneys must make reasonable efforts to prevent unauthorized access to client information. A technique that bypasses phishing awareness training and browser based protections entirely is exactly the kind of risk that a "reasonable efforts" standard is meant to anticipate. Recommendation 25-1's push toward documented cybersecurity assessments also applies directly here, since firms need a record showing they evaluated risks like signed binary abuse, not just generic phishing threats.

What to do this week

1. Confirm that conditional access policies are enabled in Microsoft 365 so tokens are tied to trusted devices and locations.
2. Review and shorten OAuth token lifetimes where your license tier allows it.
3. Audit which third party applications currently hold delegated access to your firm's Microsoft account.
4. Document this review, dated and specific, as part of your ongoing cybersecurity assessment record.

How ArisGate helps

This is precisely the kind of gap ArisGate exists to close. Solo and small Florida law firms should not have to interpret vendor security research on their own to know if they are exposed. Schedule a free security audit with ArisGate this week and let us check your firm's token and access settings before someone else does.