NBC.com has been hacked to spread malware to visitors via a tactic known as drive-by download.

On Thursday, researchers discovered the site was infected with the Citadel banking trojan, which is distributed in the RedKit exploit kit, previously used to serve Java-based malware.

It's unclear how many users were affected, though the threat impacted other pages beyond NBC.com, including the page for "Late Night with Jimmy Fallon." 

An NBC spokeswoman told The Huffington Post that the issue was resolved by 4 p.m. EST, though she was not aware of how long the pages were compromised.