Snapchat on Thursday confirmed that millions of user accounts were compromised in a recent breach that exposed phone numbers and user names. Anonymity is a key aspect of the Snapchat service for many people, some of whom use the messaging app to exchange risqué photos and videos without revealing their identities. As such, users were not happy to learn that approximately 4.6 million Snapchat accounts were exposed in this latest breach. To compound matters, however, Snapchat has confirmed in a statement that it knew about the security vulnerability that led to the breach for months but failed to fix it. “A security group first published a report about potential Find Friends abuse in August 2013,” Snapchat said in a statement.