There is a spike in phishing emails containing malicious QR codes as cybercriminals increasingly exploit QR codes.
Cybercriminals are using QR codes in emails more frequently because they provide a simple and cost-effective way to conceal malicious URLs, evading detection by many protective solutions.
Cyber experts say the QR codes are often embedded directly in email bodies or, even more commonly, within PDF attachments, an evolution that both masks phishing links and encourages users to scan them on mobile phones, which may have weaker security than work PCs.
Malicious QR codes commonly appear in mass phishing campaigns as well as targeted ones.
Links embedded malicious QR codes may lead to:
- Phishing forms impersonating login pages for services like Microsoft accounts or internal corporate portals, designed to steal usernames, passwords, and other credentials.
- Fake HR notifications urging employees to review or sign documents, such as vacation schedules, or even view lists of terminated staff, ultimately directing to credential-stealing sites.
- Fraudulent invoices or purchase confirmations in PDF attachments, often combined with vishing (voice phishing) tactics that prompt victims to call provided phone numbers to “cancel” or clarify the transaction, enabling further social engineering attacks.
These tactics exploit trust in routine business communications, leading to credential theft, account takeovers, data breaches, and financial fraud.
“Malicious QR codes have evolved into one of the most effective phishing tools, particularly when hidden in PDF attachments or disguised as legitimate business communications like HR updates.
“The explosive growth in November 2025 highlights how attackers are capitalising on this low-cost evasion technique to target employees on mobile devices, where protection is often minimal.
“Without advanced image analysis at the email gateway and safe scanning practices, organisations are left vulnerable to credential compromise and downstream breaches,” says Roman Dedenok, Anti-Spam Expert at Kaspersky.
To defend against this escalating threat, Kaspersky recommends educating employees on cybersecurity and deploying a mail server security solution for Mail Server that provides trusted and secure corporate email exchange, countering spam, email-borne infections, all forms of phishing, business email compromise (BEC), QR code attacks, and other threats.