10/08/2026
A QR code can move a phishing attack from a protected business computer to an unmanaged personal phone in seconds.
This is quishing: phishing delivered through a QR code. Attackers place codes in emails, PDFs, invoices, vendor statements, appointment confirmations, physical mail, and parking or event signage.
The structural gap is simple. A QR code is unreadable until someone scans it, so email filters and link scanners cannot pre-screen the destination. The phone may not have endpoint detection, DNS filtering, a managed browser profile, or the business controls applied to company devices.
The result may be a lookalike Microsoft 365 or QuickBooks Online login page, a real-time MFA prompt relayed by an attacker, or a fake document viewer that installs an information-stealing app.
For law firms, accounting firms, financial services companies, and medical practices, the impact is operational: compromised email can be used to send invoice or payment-change requests, client and financial data may be exposed, filing or court deadlines can be missed, and accounts may remain locked while access is reset. Trust takes longer to restore.
The practical rule is straightforward:
Treat QR codes from email, chat, or unexpected mail as untrusted. Type the website address yourself. Verify payment or banking changes using a known phone number, not a link or code. Route document and payment requests through a standard channel. Where business access is necessary, use managed, compliant devices and phishing-resistant MFA such as passkeys or FIDO2 security keys. Make reporting quick and blameless so a suspicious scan is surfaced in minutes, not days.
The Human Firewall is not employees trying harder. It is a clear structural rule, supported by secure email, managed endpoints, MFA, security awareness, and a fast reporting path. That is how long-term operational continuity is built.