The following scenarios walk through realistic attacks from the defender's perspective: how each is prevented, detected, contained and recovered from, and what risk remains. They describe defensive behaviour only.
| Stage |
Description |
| Attack |
An adversary controls the Wi-Fi or carrier network and records or manipulates traffic (ATT&CK: Adversary-in-the-Middle). |
| Prevention |
TLS with AES-256-GCM and hybrid post-quantum key exchange where the client supports it; certificate validation against the customer CA; certificate pinning on desktop and mobile; device client certificates; E2EE inside TLS. |
| Detection |
Certificate errors on clients; pin mismatch refusals. |
| Containment |
Move users to trusted networks or VPN; revoke sessions if tokens may have been captured. |
| Recovery |
Rotate token secrets if interception of tokens is suspected. |
| Residual risk |
Metadata visible to the network; content remains end-to-end encrypted, with post-quantum protection from PQXDH and SPQR. |
| Stage |
Description |
| Attack |
An attacker gains code execution in the API container. |
| Prevention |
Content keys absent from the server; signed device lists, so the server cannot add a device that receives copies; non-root containers; least-privilege access to secrets. |
| Detection |
Unexpected processes or traffic (customer host monitoring); audit anomalies; clients reporting decryption failures or unexpected devices. |
| Containment |
Isolate the host; stop the installation if necessary. |
| Recovery |
Rebuild from a verified release; rotate all server secrets; force re-authentication; review device inventories. |
| Residual risk |
Metadata and notice broadcasts observed until the server is isolated; content stays end-to-end encrypted. |
| Stage |
Description |
| Attack |
A phone is stolen while locked. |
| Prevention |
OS encryption; app passcode or biometric; SQLCipher; keys wrapped by a hardware key (Secure Enclave, StrongBox or TEE); wipe after failed unlocks. |
| Detection |
User reports loss. |
| Containment |
Mark lost: the device is refused by the server and receives no new messages. |
| Recovery |
Remote wipe after confirmation; issue a replacement device; rotate identity if appropriate. |
| Residual risk |
Forensic attacks on the OS if the device was unlocked or vulnerable. |
| Stage |
Description |
| Attack |
An administrator tries to read communications or cover activity. |
| Prevention |
No content keys on server; RBAC; administrator security keys; signed device lists; audit chain; separation of duties. |
| Detection |
Audit review; SIEM copy; chain verification; identity changes shown to every peer. |
| Containment |
Revoke the administrator; preserve evidence. |
| Recovery |
Review and reverse changes; review device approvals made by that administrator. |
| Residual risk |
Access to metadata within the administrator's role. |
| Stage |
Description |
| Attack |
An attacker resubmits captured API requests or messages. |
| Prevention |
TLS; libsignal duplicate detection; single-use tokens; idempotency keys; webhook timestamps. |
| Detection |
Duplicate-message errors; refresh-token reuse events. |
| Containment |
Device revoked automatically on refresh reuse. |
| Recovery |
User re-authenticates. |
| Residual risk |
Minimal. |
| Stage |
Description |
| Attack |
An attacker obtains a user's password. |
| Prevention |
TOTP required; lockout; rate limits; device caps and approval. |
| Detection |
Failed TOTP events; new-device events; lockouts. |
| Containment |
Reset password; suspend account if needed. |
| Recovery |
Re-enrol TOTP if the second factor may be exposed. |
| Residual risk |
Social engineering of the user; administrators use phishing-resistant security keys. |
| Stage |
Description |
| Attack |
An attacker tries to add a device to an account. |
| Prevention |
Device caps without eviction; administrator approval mode; trusted-phone linking with TOTP and signature; a device absent from the account's signed device list receives no messages. |
| Detection |
Pending-device notifications; device-approved events. |
| Containment |
Reject or revoke the device. |
| Recovery |
Review account security; rotate credentials. |
| Residual risk |
Social engineering of the user or an approver. |
| Stage |
Description |
| Attack |
A database copy is exfiltrated. |
| Prevention |
E2EE content; Argon2id; encrypted secret fields; tombstoning. |
| Detection |
Data-loss detection (customer). |
| Containment |
Rotate field and TOTP keys if keys may also be exposed. |
| Recovery |
Assess metadata disclosure; consider password resets. |
| Residual risk |
Account and communication metadata in the copy. |
| Stage |
Description |
| Attack |
Backup media is lost or stolen. |
| Prevention |
Archive encryption with a passphrase-derived key; E2EE content. |
| Detection |
Custody records. |
| Containment |
Treat as potential exposure of installation secrets. |
| Recovery |
Rotate secrets and unseal material if the passphrase may be weak or exposed. |
| Residual risk |
Offline guessing of a weak passphrase. |
| Stage |
Description |
| Attack |
A tampered package is introduced in transit. |
| Prevention |
Signed manifest with sequence number and expiry; per-archive SHA-256; offline verification; signed timestamp on connected upgrades; customer staging. |
| Detection |
Hash or signature mismatch; expired, replayed or lower-sequence manifest refused. |
| Containment |
Reject the package. |
| Recovery |
Obtain a fresh copy through an independent channel. |
| Residual risk |
Compromise upstream of signing. |
| Stage |
Description |
| Attack |
A device holding history is lost and may be unlocked later. |
| Prevention |
Local encryption; lock; disappearing messages where used. |
| Detection |
Loss report. |
| Containment |
Lost mode; remote wipe. |
| Recovery |
Replacement device; history on lost device not recoverable by the organisation. |
| Residual risk |
Content already viewed on an unlocked device. |
| Stage |
Description |
| Attack |
A member must lose access immediately. |
| Prevention |
Removal takes effect in the send transaction; future fan-outs exclude their devices; downloads require active membership. |
| Detection |
Membership-change records. |
| Containment |
Removal; device revocation if the person is leaving. |
| Recovery |
Consider rotating any shared secrets discussed. |
| Residual risk |
The removed user keeps whatever they already read or saved. |
