A silent revolution in phishing tactics is underway. Over the last six months, the SVG image format has emerged as a preferred delivery method for malicious payloads in email-based attacks.
Security experts across the industry are raising the alarm. More than a dozen cybersecurity firms, including AhnLab, Cloudflare, Forcepoint, Intezer, Kaspersky, Keep Aware, KnowBe4, Mimecast, Sophos, Sublime Security, Trustwave, and VIPRE, have all reported a marked surge in SVG-based threats. According to Sublime Security’s Q1 2025 report, SVG payloads now represent 1% of all phishing attempts detected. More strikingly, Sublime observed a staggering 47,000% increase in SVG payload usage compared to the last quarter of 2024.
Why SVGs? Because they’re not really images
The core of this evolution lies in the very nature of the SVG format. While commonly perceived as an image type, SVGs, or Scalable Vector Graphics, are far more dangerous under the surface. Rather than containing actual pixel-based graphics, SVGs are XML files that describe images using mathematical instructions. When a browser or email client opens an SVG, it does not display a picture, it interprets code that draws one in real time.
But SVGs don’t stop at image rendering. What makes them uniquely suited for phishing is their ability to embed HTML and JavaScript, the same foundational elements of modern websites. Threat actors have caught on. Instead of tricking users into clicking links to malicious websites, the phishing page can be rendered directly within the image itself.
This tactic allows attackers to embed credential-harvesting forms inside email signatures, corporate logos, or any seemingly benign visual element. Once opened, the email client renders a phishing page locally, sending harvested data back to the attacker. In some cases, this method can even bypass multi-factor authentication.
Weaponized without a click
In certain attacks, users do not even need to interact with the SVG. Simply opening the email triggers a script that redirects them to a phishing site. This seamless redirection is invisible, instantaneous, and profoundly dangerous.
Cloudflare summed it up clearly: “SVGs are not just images, they are programmable documents. When rendered in a browser, they become active content, capable of executing scripts and other manipulative behavior.”
A persistent and evolving threat
The use of SVGs in phishing campaigns is not just a trend. It signals a deeper shift in attacker methodology. Unlike previous payload fads that quickly faded, this one offers a blend of stealth, interactivity, and execution power that makes it extremely effective.
Unless major email providers such as Gmail, Hotmail, and iCloud Mail take aggressive steps to scan SVG content, restrict interactive elements, or block SVGs entirely, this technique is unlikely to disappear. Until then, security teams must remain vigilant, and organizations should reassess how SVGs are treated in their email infrastructure.
ZENDATA Cybersecuritxy continues to monitor this evolving threat landscape and remains committed to protecting its clients and partners from next-generation phishing attacks.
