QR code scanning enhances email security by closing a gap that traditional defenses often overlook: the threats hidden inside images. Instead of relying only on visible links or header data, modern email protection now inspects every QR code embedded in messages, attachments, and even layered graphics.
One Entropy study on security offers, “The ordinary data content (such as a URL) can be extracted correctly from the generated QR code… however, only authorized users with the secret key can further extract the concealed confidential information.”
With features like Paubox Inbound Email Security’s built-in QR code scanning, the system automatically extracts the destination behind each code and checks it for signs of phishing or fraud before the message ever reaches the user’s inbox. This shifts protection from a reactive model, where users must recognize danger after scanning, to a preventive one that blocks threats at the gateway.
This approach is especially effective against business email compromise and credential-harvesting campaigns, where attackers rely on trust and urgency rather than obvious technical red flags.
By decoding and validating QR content automatically, email security platforms add a visual-threat layer that works alongside existing controls like SPF, DKIM, and DMARC. The result is a more complete defense: impersonation attempts are stopped earlier, replay tactics are limited through time-sensitive checks, and users are protected from ever being exposed to malicious destinations.
Quishing, short for ‘QR code phishing’, is a newer version of traditional phishing, where attackers hide malicious links inside QR codes and place them in emails. Victims are encouraged to scan a barcode with their phones, which feels safer and more familiar. The sense of trust is exactly what criminals exploit. Once scanned, the code can quietly send users to fake login pages or trigger harmful downloads, bypassing many of the protections people rely on to spot danger in standard email links.
These attacks usually arrive disguised as routine messages from banks, coworkers, or service providers, urging quick action with lines about account problems, missed deliveries, or limited-time offers. The QR code does the rest, redirecting victims to attacker-controlled sites that steal credentials or hijack active sessions, often slipping past filters designed to scan only visible hyperlinks. Guidance from the FBI’s Internet Crime Complaint Center has flagged this technique as a growing threat, warning that QR-based scams are increasingly being used in email campaigns to sidestep traditional security checks.
QR codes slip so easily into phishing emails without raising alarms. Most security systems are built to scan visible links, not images, so a QR code can look harmless even when it leads somewhere dangerous. When people scan those codes with their phones, often outside the reach of corporate security tools, the risk increases even more.
It fits with what researchers in Computer Fraud & Security have observed about modern phishing: attackers are no longer relying on mass spam, but precision tactics, like “targeting victims with a laser-guided rifle instead of a machine gun.” What makes this tactic especially effective is the mix of psychology and technology behind it.
Cybercriminals dress up malicious QR codes as everyday actions: confirming a payment, resetting a password, or checking a missed delivery. These messages play on familiar pressure points like urgency and authority, nudging people to act before they stop to think.
On the technical side, QR codes allow attackers to bounce victims from email to mobile devices and then to constantly changing phishing sites, making it harder for defenders to block them through traditional blacklists or network monitoring. The scale of the problem is hard to ignore as 86% of email attacks now rely on ‘malwareless’ techniques like phishing and impersonation, showing just how much today’s threats depend on deception.
BEC attacks have exposed a blind spot in how email security works today. QR codes are usually treated as harmless images or attachments, so they slip past the URL scanners and content filters built to catch suspicious links. Once a user scans one on their phone, though, that sense of safety disappears.
Even advanced machine-learning tools that do a great job spotting risky language or fake sender details often miss what’s hidden inside a QR code, simply because they aren’t designed to read visual data. A detector can flag a strange phrase in an email, but it can’t see a malicious link tucked inside a square barcode.
As one Frontiers in Artificial Intelligence study on phishing and social engineering explains, “By using social engineering tricks, the message can deceive the recipient into acting in the attacker’s favor, even without the need for malicious links or attachments sent digitally.” QR-based attacks fit that pattern perfectly, relying more on human instinct than technical loopholes.
QR codes avoid real-time inspection because they only ‘come alive’ after delivery, when someone scans them on a personal device, well outside the reach of most corporate security systems. Traditional defenses can’t easily check what’s embedded in those codes, whether that’s a time-sensitive redirect or device-specific data used to make an attack look legitimate.
And because many detection models are trained on older phishing patterns, they struggle to keep up with newer QR-based scams, letting too many of them slip through. The result is a growing gap where email threats quietly jump from the inbox to the mobile world, carrying risks that older security tools were never built to handle.
Tools like Paubox’s QR code scanning add real value by automatically reading the codes hidden in emails and checking where they actually lead before a user ever pulls out their phone. Instead of treating QR codes like harmless images, these systems look at them the same way they would a suspicious link, breaking them down, validating what’s inside, and stopping threats early.
Behind the scenes, technology has come a long way. Visual recognition models can now tell the difference between a legitimate code and one that’s been tampered with, spotting subtle changes that humans would never notice. The study ‘Innovative QR Code System for Tamper-Proof Generation and Fraud-Resistant Verification’ shows these systems reaching accuracy rates above 99.28%, it means far fewer dangerous codes make it through to inboxes.
See also: HIPAA Compliant Email: The Definitive Guide (2025 Update)
QR codes themselves are neutral, but the links or actions they trigger can be risky.
A regular scanner just opens whatever is inside the QR code. A secure scanner analyzes the content first, looking for phishing links, malware, or suspicious behavior.
Because emails often appear legitimate, and QR codes inside them can move the attack from a secured work computer to a personal phone with fewer protections.