Proofpoint has warned that generative AI is changing how malicious emails are written and targeted. According to examples shared by the company at its Protect 2026 conference, attackers can now produce more fluent, personalised and varied phishing messages, weakening older detection approaches that relied heavily on recurring behavioural patterns such as poor grammar, generic wording or reused templates.

While this is a company assessment rather than an independent regulatory finding, the direction is significant for businesses because email remains one of the most common starting points for fraud, credential theft, malware delivery and business email compromise.

What happened

Proofpoint reported that generative AI is reducing some of the traditional warning signs that helped both users and email security tools identify malicious messages. In the past, phishing campaigns often revealed themselves through awkward language, obvious template reuse and broad, impersonal pretexts. The company says AI-generated content is now making those signals less reliable because messages can be tailored to a specific recipient and written in more natural language.

The practical implication is not that all existing email security controls suddenly stop working, but that behaviour-only detection becomes less dependable when the attacker can generate high-quality, highly variable content at scale.

Why it matters for European businesses

For European SMEs and larger organisations alike, phishing is not only an IT problem. It can directly affect finance, customer service, HR, procurement and executive teams. If malicious emails become more convincing, companies may see higher risk in several areas:

• Credential theft: more believable login-related emails can lead to compromised Microsoft 365, Google Workspace or SaaS accounts.
• Payment fraud: tailored business email compromise attempts may be more persuasive when they reflect a company’s language, structure or current projects.
• Ransomware and malware: phishing remains a common delivery route for initial access and malicious attachments or links.
• Operational disruption: successful attacks can interrupt sales, finance processes, customer communications and internal workflows.
• Compliance and privacy exposure: a compromised account can lead to unauthorised access to personal data, raising GDPR and incident response implications.

This trend also matters because many businesses still rely on employee suspicion of obviously poor phishing emails as a first line of defence. If generative AI removes those visible errors, organisations may need to assume a lower margin for human error and invest more in layered controls.

Who may be affected

The issue is relevant across sectors, but some groups may be especially exposed:

• SMEs with limited in-house security teams and lighter email protection stacks.
• E-commerce companies handling customer communications, payment flows and multiple SaaS platforms.
• Marketing and sales teams that regularly open external attachments, links and campaign-related messages.
• Finance and procurement teams that approve invoices, supplier changes and bank details.
• Regulated businesses that face greater consequences if compromised accounts expose sensitive or personal data.

Businesses that operate in multilingual environments may also be affected, as generative AI can help attackers produce more natural messages in different European languages.

What companies should consider

Based on the shift described by Proofpoint, companies should review whether their email security strategy depends too heavily on user judgement or older content patterns alone.

• Strengthen layered email security: combine content analysis with authentication controls, link protection, attachment scanning and account anomaly detection.
• Enforce phishing-resistant authentication where possible: stronger MFA and modern identity controls can reduce the impact of stolen credentials.
• Review staff awareness training: update training materials so they no longer focus mainly on spelling mistakes or poor formatting as the main phishing indicators.
• Protect high-risk workflows: add verification steps for invoice changes, payment requests, account resets and sensitive data requests.
• Monitor cloud accounts and SaaS access: suspicious sign-ins, forwarding rules and unusual mailbox behaviour can indicate compromise after a phishing event.
• Test incident response readiness: ensure teams know how to isolate accounts, reset sessions and assess possible data exposure quickly.

For European businesses, the broader lesson is clear: as attackers use generative AI to improve social engineering, email security needs to depend less on obvious human-visible red flags and more on layered technical controls, identity security and process discipline.