A 16-year-old security researcher found that Titan, an internal Microsoft analytics service, did not verify the signatures on its login tokens, allowing him to impersonate an administrator and run queries against data stores estimated at 17.3 trillion rows, Help Net Security reported Monday. Microsoft closed the hole in September and paid him a $5,000 bug bounty.

What Happened

The researcher, who goes by Faav, found the flaw with Antares, an AI-driven bug-hunting tool he built himself. According to his account, Antares spent about ten days probing Titan's authentication and chasing hundreds of leads before a final idea from Faav produced the breakthrough.

Titan's web interface was only reachable over Microsoft's VPN, but an API route, /v2/Query, was exposed publicly and accepted raw SQL queries from any request carrying an authorization header. Faav noticed that the token payload could change while the signature stayed the same, a sign that Titan was not checking signatures at all. It accepted JSON Web Tokens with the algorithm field set to "none" and an empty signature.

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That got a request past authentication but not past the user lookup. After Antares tried standard email formats in the token's user field without success, Faav set the value to "admin." That matched user ID 1, which carried the Admin role and gave him full SQL query access.

Why It Matters

Titan was connected to 17 databases holding an estimated 17.3 trillion rows, including historical and duplicated entries. The accessible data included about 25,000 platform account and email entries, 17,990 employee email addresses and 15,001 employee organization records with job titles, departments and reporting lines. Bing analytics tables with search queries, identifiers and location data derived from IP addresses were also reachable; the write-up cites only two sample rows from them. Because the same Microsoft identifiers appeared across several datasets, records could in principle have been linked together to build profiles.

The underlying bug is one of the oldest in token-based authentication. JWT libraries have long been warned against honoring the "none" algorithm, because a token without a checked signature is just a claim that anyone can write. Finding it on an internal service holding employee and search data shows how internal tools, often assumed to be protected by network controls like a VPN, can end up with a public path that bypasses those controls.

The Disclosure

Faav reported the issue to the Microsoft Security Response Center on Sept. 5 and was asked to stop testing. Microsoft secured the endpoint on Sept. 9 and awarded the bounty on Sept. 17. He said he never touched customer data or personal information, did not try to identify anyone from the Bing samples and did not link records across datasets.

Microsoft said the coordinated disclosure helped it protect customers by hardening its services. Faav also said Microsoft reviewed his write-up before publication, asking for some sections to be removed and for the description of the impact to be reworded.

What to Watch

The case is another example of automated, AI-assisted tools surfacing well-known classes of flaws faster than manual review. Microsoft says it has hardened the service. Open questions are whether it explains how Titan's query endpoint came to be publicly reachable, whether it audits other internal services for the same token-validation gap, and whether Faav releases Antares or publishes further findings from it.