E2EE messaging threat model

After Snowden’s revelation, E2EE received a lot of attentions as a technology to protect user privacy from mass interception and surveillance of communications carried out by governmental organizations such as NSA and GCHQ. Supposedly, end-to-end encryption (E2EE) is a defence against MitM attacks …

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Adversaries

• E2EE adversary
• Malicious group member
• Malicious user
• Service provider

Assets

• Cipher
• Cloud and storage systems
• Databases
• Identity providers
• Keyrings
• Messages & Emails
• Web applications

Attack vectors

• Backdoor
• Ghost protocols
• Insecure encryption algorithms
• Unencrypted backups
• Unencrypted metadata
• Vulnerable endpoints

Attacks

• Chosen ciphertext attack
• Chosen plaintext attack
• Forgery attack
• Impersonation attack
• MitM client-to-server HTTPS attack
• MitM server-to-server HTTPS attack
• Replay attack
• Side-channel attack

Threats

• Automated verification
• Changed message order and delivery
• Data tampering
• Plaintext leaks
• Public keyring identities leakage
• TLS/SSL PKI vulnerabilities

Impacts

• ↑ Backdoors
• ↑ Usability issues