webPromedium

SyncSphere — Web Cache Deception via URL Parser Inconsistency

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Task: SyncSphere messaging platform behind nginx reverse proxy; nginx caches /share/* paths by raw URI while Express.js normalizes URL-encoded path traversal, creating a cache deception primitive. Solution: craft /share/..%2fapi%2fauth%2fsession URL that nginx caches but Express routes to the session endpoint, use admin bot /report feature to prime cache with admin's session, then steal the admin token and access /api/admin/flag.

$ ls tags/ techniques/
web_cache_deceptionpath_normalization_desyncadmin_bot_cache_primingurl_encoding_inconsistencyproxy_cache_location_matchingsession_token_theft

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