If you use LastPass, you’ll need to change your master password. According to the site’s blog:
We noticed an issue yesterday and wanted to alert you to it. As a precaution, we’re also forcing you to change your master password.
We take a close look at our logs and try to explain every anomaly we see. Tuesday morning we saw a network traffic anomaly for a few minutes from one of our non-critical machines. These happen occasionally, and we typically identify them as an employee or an automated script.
In this case, we couldn’t find that root cause. After delving into the anomaly we found a similar but smaller matching traffic anomaly from one of our databases in the opposite direction (more traffic was sent from the database compared to what was received on the server). Because we can’t account for this anomaly either, we’re going to be paranoid and assume the worst: that the data we stored in the database was somehow accessed.
Read more on LastPass.