fix(login): strip URL lures from SSO_Message banner - #5681
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norman-abramovitz merged 2 commits intoJul 22, 2026
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The /login SSO_Message query param is attacker-controllable and rendered in the login alert banner. Interpolation already escapes HTML, so this is not XSS, but the plain text can carry a URL that reads as a trusted Stratos instruction (social engineering) — e.g. /login?SSO_Message=SECURITY+BREACH...+visit+https://evil.com. Sanitize the value before display: replace URL-like tokens (schemes, www., bare domain.tld) with [link removed] and cap length. Legit messages ("You have been logged out", UAA errors) pass through unchanged. Refs cloudfoundry#5672
norman-abramovitz
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Jul 22, 2026
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LGTM - will look to improve later to see if we can keep some HTML formatting commands, but not now.
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What
/login?SSO_Message=<text>is attacker-controllable and rendered in the loginalert banner (
login-page.component.html:125, via{{ }}). Interpolationalready HTML-escapes, so this is not XSS — but the plain text can carry a
URL that reads like a trusted Stratos instruction, enabling social engineering:
Fixes the low-severity injection reported in #5672.
Change
Sanitize
SSO_Messagebefore display: strip URL-like tokens (schemes,www.,bare
domain.tld[/path]) →[link removed], then cap length to keep it astatus line. The banner stays plain-text-plus-template-styling by design — no
switch to
[innerHTML], which would turn this into a real XSS surface.Legitimate messages are untouched: the backend only emits short status text
(
authuaa.go— "You have been logged out", raw UAA error strings), none ofwhich contain URLs.
Detection note
No new logging added: the crafted request is already captured operator-side in
the frontend (nginx) access log, whose default
combinedformat records thefull request line including the query string, shipped via
cf logs. Backendlogging would be redundant (jetstream's echo logger drops the query anyway) and
would reintroduce a log-injection concern.
Tests
login-page.component.spec.ts: strips scheme/www./bare-domain URLs, caps at256 chars, and passes legit messages through unchanged.
npx vitest run --project=core login-page.component→ green; lint clean.Closes #5672