What is FluBot (Cabassous) malware's unique distribution mechanism and what made its spread particularly rapid?

• A.FluBot spread via SMS messages claiming to be package delivery notifications with a link to a fake tracking app; once installed, it accessed the victim's contact list and sent the same SMS to all contacts from the victim's number, creating an organic peer-to-peer propagation chain. This made it appear as messages from trusted friends/family, dramatically increasing click-through rates compared to random-number spam campaigns.
• B.The family propagated by exploiting an unpatched remote execution defect in the platform's message handling, and every handset on a vulnerable build was reachable without any action by the owner because the payload ran during parsing: the spread was rapid for that reason, with no social engineering step involved at all. Patched devices were immune throughout the campaign the researchers tracked. Coverage varied by region. Telemetry confirmed it.
• C.