--- title: 1M+ Emails Use Hidden Text to Dupe AI Security Filters description: Researchers at Barracuda Networks have observed over 1 million retail-themed phishing emails since April that use 'text salting' — injecting hidden, innocuous... canonical: https://daily.dev/posts/1m-emails-use-hidden-text-to-dupe-ai-security-filters-dbn4sjex7 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: 1M+ Emails Use Hidden Text to Dupe AI Security Filters | daily.dev og:description: Researchers at Barracuda Networks have observed over 1 million retail-themed phishing emails since April that use 'text salting' — injecting hidden, innocuous... og:url: https://daily.dev/posts/1m-emails-use-hidden-text-to-dupe-ai-security-filters-dbn4sjex7 og:image: https://api.daily.dev/og/posts/dBn4SJEX7.png og:image:alt: 1M+ Emails Use Hidden Text to Dupe AI Security Filters og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # 1M+ Emails Use Hidden Text to Dupe AI Security Filters **[Dark Reading](https://daily.dev/sources/dr)** · 4 min read · 1 upvotes · 0 comments ## Summary Researchers at Barracuda Networks have observed over 1 million retail-themed phishing emails since April that use 'text salting' — injecting hidden, innocuous text into HTML — to evade both traditional and AI-powered email security gateways. The technique works by hiding filler text using zero-size fonts, zero-dimension containers, or off-screen overflow, breaking up spammy content so automated filters don't flag it. Attackers are layering multiple salting methods to defeat tools that try to un-hide hidden text. LLMs are accelerating attackers' ability to generate and modify salted emails, while AI-based content analysis engines remain surprisingly ineffective against the technique. Defenders are advised to evaluate full message context — including the relationship between visible content, hidden text, links, and sender behavior — rather than relying on keyword scanning alone. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What is text salting in phishing emails and how does it evade AI security filters? Text salting is a technique where attackers hide innocuous filler words, like 'puppy' or 'book', inside the HTML of a phishing email alongside spammy trigger words, so AI and keyword-based content filters see a diluted mix rather than obvious spam language. The filler text is hidden using zero font size, zero-height viewing windows, or off-screen overflow, so a human recipient never sees it while automated scanners misjudge the message context. _Security teams tracking evasion techniques like text salting can follow developer-focused threat coverage on daily.dev._ ### How many phishing emails have been found using text salting to bypass email security? Barracuda Networks researchers observed more than one million retail-themed phishing emails using hidden text salting techniques since April, targeting recipients with fake reward and gift-card offers designed to trigger urgent clicks. Despite low-effort, obviously fake branding and formatting, these emails still slipped past secure email gateways and AI-based content analysis engines. _Anyone building or evaluating email security tooling can track findings like this via daily.dev._ ## Similar posts on daily.dev - [How AI-Generated Content is Fueling Next-Gen Phishing and BEC Attacks: Detection and Defense Strategies](https://daily.dev/posts/how-ai-generated-content-is-fueling-next-gen-phishing-and-bec-attacks-detection-and-defense-strateg-hjbgtmbld) · Security Boulevard · 0 upvotes · 0 comments - [Excuse me while I slip past your security](https://daily.dev/posts/excuse-me-while-i-slip-past-your-security-otvsdhl1g) · TechCentral · 0 upvotes · 0 comments - [Schneier on Security](https://daily.dev/posts/schneier-on-security-abiv7kd0q) · Schneier on Security · 0 upvotes · 0 comments --- Tags: [#security](https://daily.dev/tags/security), [#llm](https://daily.dev/tags/llm), [#phishing](https://daily.dev/tags/phishing), [#ai-security](https://daily.dev/tags/ai-security) [View this post on daily.dev](https://daily.dev/posts/1m-emails-use-hidden-text-to-dupe-ai-security-filters-dbn4sjex7) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"1M+ Emails Use Hidden Text to Dupe AI Security Filters","url":"https://daily.dev/posts/1m-emails-use-hidden-text-to-dupe-ai-security-filters-dbn4sjex7","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/1m-emails-use-hidden-text-to-dupe-ai-security-filters-dbn4sjex7"},"datePublished":"2026-07-16T20:14:06.831Z","dateModified":"2026-09-14T06:25:54.943Z","description":"Researchers at Barracuda Networks have observed over 1 million retail-themed phishing emails since April that use 'text salting' — injecting hidden, innocuous...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/c13794783c514236a2e62265d784e720?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/c13794783c514236a2e62265d784e720?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Dark Reading","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Dark Reading","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/dr","url":"https://daily.dev/sources/dr"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/1m-emails-use-hidden-text-to-dupe-ai-security-filters-dbn4sjex7","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":1},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"security,llm,phishing,ai-security","timeRequired":"PT4M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Dark Reading","item":"https://daily.dev/sources/dr"},{"@type":"ListItem","position":3,"name":"1M+ Emails Use Hidden Text to Dupe AI Security Filters"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/1m-emails-use-hidden-text-to-dupe-ai-security-filters-dbn4sjex7#faq","mainEntity":[{"@type":"Question","name":"What is text salting in phishing emails and how does it evade AI security filters?","acceptedAnswer":{"@type":"Answer","text":"Text salting is a technique where attackers hide innocuous filler words, like 'puppy' or 'book', inside the HTML of a phishing email alongside spammy trigger words, so AI and keyword-based content filters see a diluted mix rather than obvious spam language. The filler text is hidden using zero font size, zero-height viewing windows, or off-screen overflow, so a human recipient never sees it while automated scanners misjudge the message context. Security teams tracking evasion techniques like text salting can follow developer-focused threat coverage on daily.dev."}},{"@type":"Question","name":"How many phishing emails have been found using text salting to bypass email security?","acceptedAnswer":{"@type":"Answer","text":"Barracuda Networks researchers observed more than one million retail-themed phishing emails using hidden text salting techniques since April, targeting recipients with fake reward and gift-card offers designed to trigger urgent clicks. Despite low-effort, obviously fake branding and formatting, these emails still slipped past secure email gateways and AI-based content analysis engines. Anyone building or evaluating email security tooling can track findings like this via daily.dev."}}]} ```