RCQ Messenger Duress PIN Flaw Gave Full Access to Real Database on Android
RCQ developers discovered that their duress PIN feature on Android used the same dataKey for both real and decoy accounts, allowing anyone entering the panic code to unlock the entire message history. The original design aimed to present a believable second account but resulted in the decoy PIN acting as a master key rather than a protective boundary. On iOS the implementation was cryptographically separate yet suffered from contact wiping that made the decoy mode look suspiciously empty. After review the team switched both platforms to independent random keys, generated realistic conversation histories, and disabled network features in decoy mode to avoid server-side linkage. Legacy slots created before the fix remain marked as such and require users to set a new decoy PIN. The post-mortem also covers desktop Argon2id vault encryption, notification leakage risks, and why short PINs remain vulnerable to offline brute-force even with strong KDF parameters.
Habr•Vulnerabilities & Exploits
