Detailed Analysis
A Reddit user posted a warning on r/Anthropic about a phishing operation targeting people seeking Anthropic's official certification programs, such as the Claude Certified AI Fluency (CCAF) course. The malicious site, anthropiccertifications[.]com, has reportedly achieved high search engine rankings, positioning it above or alongside the legitimate course host, anthropic.skilljar.com. Because Skilljar (a third-party learning platform) is a less intuitive URL than a domain that directly references "Anthropic certifications," unsuspecting users searching for official training materials are more likely to click the fraudulent link first. The poster noted that the site's visual design closely mimics Anthropic's actual branding, fonts, and styling, making it difficult to distinguish from a genuine company property at a glance.
The mechanics of the scam are particularly concerning because they exploit OAuth authentication rather than simple credential harvesting. Visitors are prompted to sign in via Google Single Sign-On, which then authorizes a rogue application labeled "Claude" or "Claude for Gmail" within the victim's Google account security settings, linked to a backend Supabase instance. This grants the attackers persistent OAuth session tokens rather than just a one-time password. The scam culminates in a fake $19 "upgrade fee" paywall — a detail that should immediately raise suspicion, since Anthropic's official certification courses are free. However, the poster emphasized that the real damage occurs earlier in the flow: even users who recognize the scam at the payment screen and abandon the process have already granted OAuth access, meaning simply closing the browser tab does not revoke the attacker's session tokens or account permissions.
This incident reflects a broader and increasingly common pattern in AI-adjacent phishing: attackers piggybacking on the surging popularity of legitimate AI tools and their associated ecosystems (certifications, API keys, browser extensions, "official" apps) to harvest credentials and authorization tokens. As companies like Anthropic, OpenAI, and Google expand free educational and certification offerings to build developer and enterprise trust, scammers have a ready-made playbook: clone the branding, exploit SEO gaps around less-memorable legitimate subdomains, and use OAuth consent screens — which many users treat as routine "Sign in with Google" prompts — to gain far more durable access than a stolen password would provide. The use of a Supabase backend also illustrates how low the technical barrier has become for standing up a convincing, functional phishing infrastructure using off-the-shelf developer tools.
The practical guidance from the post is directly actionable: anyone who has visited the fraudulent domain or entered credentials should immediately navigate to myaccount.google.com/connections, locate any unfamiliar or duplicate "Claude" application, and revoke its access. More broadly, this episode underscores the importance of verifying official URLs directly from a company's primary website rather than relying on search engine results, especially for high-trust actions like SSO authorization. It also highlights a growing responsibility for AI companies to actively monitor for and take down impersonating domains, and for search engines to more aggressively flag or de-rank sites mimicking official branding — particularly when those sites are engineered to intercept OAuth tokens rather than merely spoof a login form.
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