

Pentagon-wide advisory sent to staffers on March 18 — less than a week before the screwup went public — explicitly warned against using Signal for any sharing of information, classified or not.
The advisory claimed that a “vulnerability has been identified in the Signal messenger application,” and that Russian hacking groups were “targeting Signal Messenger to spy on persons of interest” (a Signal spokesperson told NPR that the company wasn’t “aware of any vulnerabilities or supposed ones that we haven’t addressed publicly.”)
https://futurism.com/the-byte/pentagon-issued-warning-signal-messaging
Don’t forget desquamation (skin peeling)!