xoxb- Slack tokens in bundles — someone else posting as your app
Slack tokens hide in support widgets and notification demos. Detect xox-prefixed strings in served JS — free scan.
Support-chat widgets and deploy-notification demos are where Slack tokens go to be forgotten — installed once, bundled forever.
What a Slack bot token is
xoxb- bot tokens act with install-time scopes: post messages, read channels, upload files.
xoxb-0000-FAKE000000000000000The prefix is the claim: scanners and attackers alike identify the format before they know anything else about it, which is why recognition starts at the first characters rather than the last.
What it grants
Channel-scoped reach:
- Post as your app anywhere invited.
- Read channel history where scopes granted — quiet exfiltration path.
How it ends up in a bundle
Three arrival routes cover nearly every case we see:
- Live-chat widgets initialized with hardcoded tokens.
- Status pages posting build notices client-side.
Does it belong in a browser?
Server-relay notifications; widget backends hold tokens.
Rotate it
api.slack.com/apps → rotate credentials; reinstall app to distribute new token.
Find it in seconds
Open DevTools on the deployed site and search the built assets for xoxb-. If the search hits, the credential shipped; if it does not, check the chunks loaded on authenticated or interactive views, not just the landing page — the calling code often sits behind a route.
The faster path is to let a machine do the fetching. KeyDrift downloads the same JavaScript a visitor gets — HTML, every referenced chunk including ones named only in the route manifest, and the server-streamed data frameworks inline into the document — and reports credentials with a masked prefix, a fingerprint, and the exact file they live in. Paste your deployed URL into the scanner; no account needed.
Make sure it stays gone
It bears saying because it happens constantly: the fix holds until the next prompt that needs the query to return rows. Drift monitoring exists for precisely this — it diffs consecutive scans and pages you when a previously resolved finding reappears, naming the regression as a regression rather than repeating the first alert.
The bigger picture
It helps to name the economics honestly. Fixing this class of leak costs minutes when caught at deploy time and days when caught at invoice time, because by then the credential has been harvested, validated, resold or drained — often all four. Detection latency is the entire game, which is why the monitoring half of KeyDrift exists alongside the scanning half.
How KeyDrift reports this exact finding
When KeyDrift finds this on your deployment, the report shows a masked value (first 8 and last 4 characters only), a salted fingerprint for tracking, the exact chunk filename carrying it, and a severity with written rationale. Public-by-design neighbours — anon keys, publishable keys, Firebase web constants — appear as informational context rather than noise, because knowing what should be there is what makes the real findings credible.
Manual check, step by step
A five-minute version you can run anywhere: view-source on the landing page, copy every src= script URL, fetch each and search the results for xoxb-. It misses manifest-only chunks and streamed payloads — which is precisely the gap between "I checked" and "it is clean" — but it catches the loud majority and builds the pattern-recognition that makes scanner output legible.
Close the loop with monitoring
Monitoring closes the loop that one-time verification leaves open. A scheduled scan refetches everything, diffs against history, and fires only on transitions: created, regressed, resolved. Regression alerts matter most here — they fire when a previously fixed finding returns, which in agent-era codebases is less a possibility than a schedule.
Common questions
xoxp user tokens worse?
Typically yes (personal scope); detection covers the family including xapp app-level.
History reads really risky?
Decision threads, credentials shared in DMs — channel history is a dataset.
Run a free scan at keydrift.dev/scan — paste a URL or the bundle source itself, no account. Findings arrive masked, with the exact chunk they live in.