Grok Build apps left open: 35,000 reachable without sign-in
Security firm Claroc opened 35,578 apps built with Grok Build without a login, including SpaceXSI's own sales map and ad proposals. Here is how it was possible.
SUMO· the number puzzle
Dialo· learn languages by speaking
ediviewer· read EDI files like documents
giftdetect· the right gift in minutesIf you could find the address of a Grok Build app, you could probably open it. Security firm Claroc says it opened 35,578 of them without any sign-in, and two dozen belonged to staff at SpaceXSI, the company behind Grok.
What is Grok Build and what was exposed?
Grok Build turns a description typed into a chat into a working app, which the user can publish at its own address on grok.me. Claroc tried more than 43,500 addresses. Of the 37,571 still online, 94.7% opened with no login.
Most were games, landing pages and calculators. About one in ten held internal business or personal data, which Claroc estimates at 650 to 800 apps. Confirmed cases included an intensive care patient's lab results, a hospital group's roster of more than 3,500 staff and a fire department's shift board. One timesheet app carried 18 accounts with passwords in plain text.
SpaceXSI's own apps held a map of 594 strategic sales accounts and eight X advertising proposals. One, for a US federal agency, carried a confidential label. The company took its 24 apps offline after the report, Claroc said, but left other users' apps open.
How did Claroc find the apps?
Every published app gets a hostname made of random words, like name.grok.me. Nobody had to guess one. When someone opens an app, that name lands in passive DNS databases, which log internet lookups and can be searched by anyone with an account. Shared chats from Claude, ChatGPT and Gemini keep the secret part of the link in the path, which DNS never sees, Claroc said.
The publish screen offered "Anyone with the link" as the proposed setting, next to "Invited users" and "Only you". Claroc also found that in a test app, Grok's code added anyone signing in with Google to a team before checking membership, so an outsider could read, edit and delete records.
A representative for Cursor, which SpaceX bought in August, said apps are private by default and nothing goes public unless the creator shares it. Claroc replies that the people behind the open apps went through every publishing step. Its co-founder Asaf Aprozper says Lovable, Bolt and Replit apps share the exposure, but that Grok is where the firm found by far the most sensitive company data.
Claroc sells security tools for AI-built apps. It wants "Only you" as the default, harder-to-guess paths and a warning when an app has a database but no sign-in. It is notifying affected organisations itself. In July, Grok Build also sent entire Git repositories to xAI's servers.
Apps worth a look
SUMO: the number puzzleTap the right tiles, add them up, hit the target. Easy to learn, hard to master. Free, for all ages.
Dialo: learn languages by speakingTalk to an AI conversation partner; every sentence comes back corrected and explained in your language. 9 languages, A1 to C2.
ediviewer: read EDI files like documentsOpen EDIFACT and X12 messages, see every segment explained, convert to JSON/XML, export PDF and Excel. Runs locally, no upload.
giftdetect: the right gift in minutesPick who it is for, the occasion and their personality. The search engine reads product descriptions from local shops and ranks what fits. Free, no sign-up.
