ClickFix operators moved the payload into text only the summarizer can see
Forcepoint's X-Labs found short-lived ClickFix domains carrying white-on-white characters and zero-width spaces, which puts the trust boundary for any agent you point at the open web inside your own extraction code.
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What happened
- Forcepoint X-Labs found ClickFix pages whose HTML carried white-on-white characters and zero-width spaces, text a person viewing the page cannot see and a language model reads in full.
- Across 90 days of the company's global telemetry, the associated domains surfaced in short bursts and vanished within hours, many of them alive for less than a single day.
- Early samples were tied to Rhadamanthys, DarkGate and Poseidon, families Forcepoint says all use invisible prompts to bypass security filters.
- A Booking.com impersonation at booking.com-reactivate[.]de showed a session-verification CAPTCHA, then walked victims through clipboard steps into PowerShell, Terminal or shell to run preloaded strings.
Why it matters
- exposure Whoever controls a URL an employee drops into Copilot, Gemini or ChatGPT gets a write channel into an output that Forcepoint says users accept without question, which makes the page author a participant in your internal reporting.
- constraint Reputation feeds keyed on domain names cannot arrive in time for infrastructure that expires the same day, so the check has to move to the content of the fetched page rather than the name it was served from.
- decision Someone on your team now owns whether links and code fragments that emerge from a summary are permitted to become clickable, runnable, or the input to a further tool call.
- contradiction Forcepoint calls the summarizer path an attack still being tested while the case it documents end to end is the older human-paste chain, so the size of this exposure currently rests on telemetry rather than on a demonstrated poisoned summary.
Invisibility is a property of the renderer, not of the bytes. A summarize-this-URL path normally goes fetch, strip tags, feed text to the model. Nothing in that sequence evaluates the rule that paints a character white on a white ground, and nothing weighs a zero-width space at zero. The hidden string lands in the context window with the same standing as the `<h1>`. Your extractor is more thorough than your users, which is the whole exploit.
Forcepoint's account of the CSS-based variant is that the model reads those embedded strings as part of its instructions and returns a summary carrying encoded links or fragments of executable text [14]. The post's own one-line version is blunter: "if an AI can read everything, it can also be deceived by anything" [11].
One page, two readers. On the Booking.com impersonation X-Labs walks through, hidden JavaScript collected data and staged an obfuscated downloader and credential stealer once the victim finished the on-screen steps [7], while Forcepoint reads the invisible layer of such pages as aimed at summarizers or automated scanners reviewing the same content [8]. Earlier ClickFix, including the Odyssey Stealer macOS work X-Labs published, needed a person to paste [9]; the CSS variant adds a reader that executes nothing and still shapes what the person is told.
Two claims in the post carry different weight. Three distinct payload families turn up in the early samples [16], which suggests the invisible-prompt trick is circulating between operators rather than sitting in one crew's toolkit. The geography is softer. Forcepoint reads bursts in North America, Western Europe and Southeast Asia as tracking the regions with highest enterprise AI adoption [12]. For that to transfer to your own risk model, sensor coverage would have to be roughly even across those regions and across the ones that stayed dark. Vendor telemetry maps the install base before it maps the adversary.
Adoption cost. Render first and then extract, and you get visibility-aware text at the price of a headless browser per fetch, which is real latency and real CPU on every page an agent reads. Normalizing text at ingest is far cheaper, but put the strip behind a flag and log what you removed, so the day someone's non-Latin content loses characters you can find out why rather than guess. The part I would not trade is authority. Text that arrived over a fetch is data, a summary of that text is also data, and nothing in either should become a tool call, a click target or a clipboard write without a human in between.
In my context that puts the trust boundary at the fetch. The config line that proves you meant it is the one that records what your extractor threw away.
What to watch
- Whether X-Labs publishes a page-and-output pair showing which summarizer emitted which encoded link, turning the testing-phase read into a measured one.
- Whether any browsing pipeline ships visibility-aware extraction or documented zero-width normalisation as a default rather than an option.
- Whether the hours-long domain bursts consolidate into a sustained campaign with a payload family beyond the three already tied to samples.
Clarity's read
What the record supports and how the coverage leans. The claims behind it follow.
Reality
- Evidence30
- Adoption22
- Hype gap+40
- Incentives75
- Confidence38
Claim ledger
Ranked by verification strength, evidence, and original report placement.
- [1]
The activity involved a series of short-lived domains, many active for less than a day, appearing and disappearing across networks.
- [2]
Over a 90-day period, ClickFix-related domains appeared in short bursts before disappearing within hours.
- [3]
Late last year, Forcepoint X-Labs researchers began noticing a pattern in telemetry from recent ClickFix detections.
- [4]
Inspection of the pages' HTML uncovered strings of white-on-white characters and zero-width spaces; this hidden text was invisible to users but fully readable to large language models.
- [5]
Forcepoint characterises the activity as an attack still in its testing phase, with attackers testing how summarizers process malicious text and which prompts can evade detection.
- [6]
In a Booking.com impersonation campaign hosted at hxxps://booking.com-reactivate[.]de/uri.html, the page displayed a CAPTCHA claiming to verify the user's session, then guided victims through steps such as copying commands to the clipboard and confirming browser troubleshooting, socially engineered to open PowerShell on Windows, Terminal on macOS or shell on Linux and paste preloaded strings that executed the malicious payload.
- [7]
Hidden JavaScript on that page collected data and prepared to drop an obfuscated payload once the steps were completed; the dropped code used encoded strings that unfolded into a downloader and credential-stealer when executed.
- [8]
Forcepoint describes the design as multi-stage: the visible CAPTCHA misleads users while invisible payloads target summarizers or automated scanners reviewing the same page.
- [9]
Earlier ClickFix forms, including those documented in X-Labs analysis of the Odyssey Stealer macOS campaign, depended on human interaction such as pasting PowerShell commands or clicking invisible buttons behind CAPTCHAs and fake verification screens.
- [10]
Forcepoint describes the attack as targeting the AI interpreting the content rather than the person viewing it.
- [11]
Forcepoint writes: "if an AI can read everything, it can also be deceived by anything."
- [12]
Activity clusters emerged across North America, Western Europe and Southeast Asia, which Forcepoint describes as the regions with the highest enterprise AI adoption.
- [13]
Early samples carried payloads tied to Rhadamanthys, plus others including DarkGate and Poseidon, which Forcepoint says all use invisible prompts to bypass security filters.
- [14]
In the CSS-based ClickFix variant, invisible CSS elements or zero-width characters embed hidden prompts within a page; the LLM reads these cues as part of its instructions and produces a summary that includes encoded links or snippets of executable text.
- [15]
Forcepoint says AI summarizers including Copilot, Gemini and ChatGPT have embedded themselves in enterprise workflows, digesting reports, emails and web pages, with users trusting the outputs without question.
- [16]
Three distinct malware families are named as tied to payloads in the early samples: Rhadamanthys, DarkGate and Poseidon.
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Sources
1 independent publisher whose own reporting we read for this story.
- How Invisible Prompts Turn AI Summaries into Attack Vectors
forcepoint.com
1 article · August 30, 2026
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- ForcepointFollow
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- Rhadamanthys stealerFollow
- DarkGateFollow
- PoseidonFollow
- Odyssey StealerFollow
- Lumma StealerFollow
- Microsoft CopilotFollow
- ChatGPTFollow
- Booking.comFollow
- GeminiFollow