{"ok":true,"trend":{"id":613591,"platform":"mastodon","region":"global","key":"a jwt validator that checks every claim but never the signature tells the attacker which claim to fix next. faav's micro","title":"A JWT validator that checks every claim but never the signature tells the attacker which claim to fix next. Faav's Micro","url":"https://mastodon.social/@shellonline/117365785790088751","first_seen":"2026-10-01T13:32:13.233891Z","last_seen":"2026-10-01T13:32:13.233891Z","last_rank":1,"peak_rank":1,"last_volume":3,"peak_volume":3,"seen_count":1,"score":0.72015625,"category_hint":"cybersecurity","section":"technology","category":"cybersecurity","summary":"A security writeup by Faav describes a Microsoft token validation flaw where a JWT with the 'alg:none' bypass was accepted despite failing every other check. Because the validator returned granular errors — wrong tenant, wrong audience, app allowlist rejection, then 'User not found' — it effectively guided the attacker through each requirement. The writeup also mentions an AI-driven hackbot spending ten days probing email-style attack paths.","why":"It highlights how detailed error messages in authentication systems can hand attackers a roadmap, a timely concern as AI tools automate exploitation.","tone":"neutral","entities":["Faav","Microsoft","JWT"],"summarized_at":"2026-10-01T13:33:14.865431Z","meta":{"tag":"cybersecurity","via":"scan","kind":"status","lang":"en","instance":"mastodon.social","tag_uses":1726},"nw":null,"promo":null,"kind":null,"importance":null,"hidden":false,"hide_reason":null,"judged_at":null,"title_en":"JWT validator skipped signature check, exposing step-by-step flaw","section_name":"Technology","category_name":"Cybersecurity","timeline":[{"captured_at":"2026-10-01T13:32:13.233891Z","rank":1,"volume":3}],"posts":[{"platform":"mastodon","url":"https://mastodon.social/@shellonline/117365785790088751","author":"shellonline","title":null,"snippet":"A JWT validator that checks every claim but never the signature tells the attacker which claim to fix next. Faav's Microsoft Titan writeup: tenant error, audience, app allowlist, then \"User not found\". An alg:none token got that far. An AI hackbot spent ten days on email-style…","posted_at":"2026-10-01T13:02:48.529000Z","likes":3}],"elsewhere":[],"window":"7d"}}