Web hosting company Namecheap is alerting users that its login systems were attacked this past month and recommending they reevaluate their passwords.

The attacks allowed a group of hackers to enter stolen credentials into Namecheap.com’s login portal to try and gain access to user accounts, according to a release. The group appears to have used fake browser software that simulates the login process users typically go through to access their Namecheap accounts.

Although most efforts were unsuccessful, said Namecheap, the company is blocking IP addresses that could be linked to the stolen password information. It’s also logging the IP addresses and exporting blocking rules across its network. That information is also available to law enforcement officials.

Namecheap suspects the stolen data could be linked to the 1 billion stolen credentials discovered last month.