It seems like we hear about a new data breach every day. Today, we’re bringing news of yet another—but this one happened in the old-school sense of the term. And it has earned the Aetna insurance giant a class-action lawsuit.

Aetna is accused of breaching the privacy rights of 12,000 customers in 23 states by snail-mailing them letters in which the words “filling prescriptions for HIV” could be read through the transparent window on the envelopes.