LotusGuild/cinny
3
0
Fork 0
Code Issues 27 Pull Requests 5 Actions Packages Projects Releases Wiki Activity

Link-mismatch warning is bypassed by adding a word to the link text, or by using a shared hosting domain (pages.dev, github.io…) #335

New Issue
Closed
opened 2026-10-05 23:37:41 -04:00 by jared · 0 comments
jared commented 2026-10-05 23:37:41 -04:00
Owner
Copy Link
Copy Source

utils/linkSafety.ts (#122) catches the classic shapes, measured with the real analyzeLink:

"https://chat.lotusguild.org/login"  → https://evil.example/login                 FLAGGED
"https://chat.lotusguild.org"        → https://chat.lotusguild.org@evil.example/  FLAGGED
"chat.lotusguild.org"                → https://chat.lotusguild.org.evil.example/  FLAGGED
"paypal.com"                         → https://xn--pypal-4ve.com/                 FLAGGED

Two easy bypasses:

"Log in at chat.lotusguild.org"      → https://evil.example/   not flagged
"chat.lotusguild.org (official)"     → https://evil.example/   not flagged
"lotusguild.pages.dev"               → https://evil.pages.dev/ not flagged
"alice.github.io"                    → https://evil.github.io/ not flagged
  1. Any whitespace in the text disables the check. hostFromText returns null when /\s/.test(text). A phish just writes a sentence ("Log in at …", "… (official)") around the trusted name.
  2. Multi-tenant hosting suffixes count as one site. registrableDomain uses a hand-made two-label list instead of the Public Suffix List, so x.github.io, x.pages.dev, x.netlify.app, x.vercel.app, x.web.app, x.blogspot.com, x.herokuapp.com etc. all collapse to the shared suffix and any two sites on it "match".

Fix:

  • Scan the text for host-like tokens (the same HOST_LIKE pattern, applied per word). If any token's registrable domain differs from the href's, flag it, ignoring the plain words around it.
  • Use the PSL (psl / tldts, both small) for registrableDomain, including the private section, which is what covers github.io / pages.dev.
  • Add the cases above to linkSafety.test.ts.

Found in the October 2026 client audit (Playwright against a local Synapse + LiveKit stack, plus code reading). Code refs are at cinny 30e2dbcd, cinny-desktop 8f67ec7, element-call 3b0050e8.

`utils/linkSafety.ts` (#122) catches the classic shapes, measured with the real `analyzeLink`: ``` "https://chat.lotusguild.org/login" → https://evil.example/login FLAGGED "https://chat.lotusguild.org" → https://chat.lotusguild.org@evil.example/ FLAGGED "chat.lotusguild.org" → https://chat.lotusguild.org.evil.example/ FLAGGED "paypal.com" → https://xn--pypal-4ve.com/ FLAGGED ``` Two easy bypasses: ``` "Log in at chat.lotusguild.org" → https://evil.example/ not flagged "chat.lotusguild.org (official)" → https://evil.example/ not flagged "lotusguild.pages.dev" → https://evil.pages.dev/ not flagged "alice.github.io" → https://evil.github.io/ not flagged ``` 1. **Any whitespace in the text disables the check.** `hostFromText` returns `null` when `/\s/.test(text)`. A phish just writes a sentence ("Log in at …", "… (official)") around the trusted name. 2. **Multi-tenant hosting suffixes count as one site.** `registrableDomain` uses a hand-made two-label list instead of the Public Suffix List, so `x.github.io`, `x.pages.dev`, `x.netlify.app`, `x.vercel.app`, `x.web.app`, `x.blogspot.com`, `x.herokuapp.com` etc. all collapse to the shared suffix and any two sites on it "match". **Fix:** - Scan the text for host-like *tokens* (the same `HOST_LIKE` pattern, applied per word). If any token's registrable domain differs from the href's, flag it, ignoring the plain words around it. - Use the PSL (`psl` / `tldts`, both small) for `registrableDomain`, including the private section, which is what covers `github.io` / `pages.dev`. - Add the cases above to `linkSafety.test.ts`. --- _Found in the October 2026 client audit (Playwright against a local Synapse + LiveKit stack, plus code reading). Code refs are at cinny `30e2dbcd`, cinny-desktop `8f67ec7`, element-call `3b0050e8`._
jared added the priority: lowsecurityarea: messaging labels 2026-10-05 23:37:41 -04:00
jared closed this issue 2026-10-16 19:59:20 -04:00
Sign in to join this conversation.
No Branch/Tag Specified
Branches Tags
Labels
Clear labels
a11y
Accessibility: keyboard, screen reader, contrast, motion
 area: appearance
Client area: appearance
 area: auth-session
Client area: auth-session
 area: build-ci
Client area: build-ci
 area: calls
Client area: calls
 area: desktop
Client area: desktop
 area: media
Client area: media
 area: messaging
Client area: messaging
 area: mobile
Client area: mobile
 area: moderation
Client area: moderation
 area: navigation
Client area: navigation
 area: notifications
Client area: notifications
 area: settings
Client area: settings
 area: threads
Client area: threads
 bug
Something is not working
 dependencies
Third-party package versions and advisories
 docs
README / LOTUS_* docs wrong or missing
 duplicate
This issue or pull request already exists
 enhancement
New feature
 help wanted
Need some help
 invalid
Something is wrong
 needs-human-review
performance
Re-render storms, leaks, heavy work on hot paths
 planning
priority: critical
Data loss, security hole, or crash on a main path
 priority: high
Broken feature or serious usability problem
 priority: low
Minor issue or polish
 priority: medium
Wrong behaviour in an edge case or notable degradation
 qa
Manual QA: shipped, needs a human in a real environment
 question
More information is needed
 research
security
XSS, unsafe URLs, data leaks, auth/session
 tech-debt
Code health, dead code, fragile patterns
 ux
Usability or visual inconsistency
 wontfix
This won't be fixed
No labels area: messaging priority: low security
Milestone
No items
No Milestone
Projects
Clear projects
No projects
Assignees
Clear assignees
cole (Cole Keller) jared (Jared Vititoe) nathan (Nathan Vititoe)
No Assignees
1 Participants
Notifications
Due Date
No due date set.
Dependencies

No dependencies set.

Reference: LotusGuild/cinny#335