Criminals are using CSS to get around filters and track email usage

Cisco Talos says hackers are abusing CSS in emails The stylesheet language is used to hide content, track people's behavior, ...
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Attackers Use Unicode & HTML to Bypass Email Security Tools

Cybercriminals have been spotted using HTML/CSS and Unicode tricks to bypass tools meant to block malicious emails, marking a new twist in phishing techniques, security researchers report. Attackers ...