Failure Pattern
Browser profile sync systems propagate cookies, extensions, and sessions across devices — including compromised ones.
User Impact
The user wonders how attackers gained access to accounts even though “my laptop is clean.”
Underlying Causes
Tokens synced across devices
Extensions synced across devices
Sync as metadata, not identity-bound
Trust-Native Resolution
DTL-based identity restricts sync operations to trusted device groupings — not generic Google/Mozilla/MS accounts.
Broken Trust Assumption
Many of the most damaging breaches of the past decade occurred in environments that were fully authenticated, encrypted, and compliant.
Incidents including SolarWinds, NotPetya, Capital One, and MOVEit show a consistent pattern: attackers succeeded by inheriting trust, not by breaking it. Security controls validated access, but not intent.