You might be talking about the way the CIA reused code to communicate with sources in Iran in its China operations? Then got a ton of people killed by being stupid/lazy - despite internal whistleblowers going to Congress to warn them it was dangerous?

https://www.telegraph.co.uk/technology/2018/11/03/dozens-us-...

Something similar happened in Lebanon IIRC. Lazy reuse of tradecraft - a pizzeria and some mobiles I think it was.