Hackers recently released a list of nearly half a million Fortinet VPN usernames and passwords onto the Dark Web. The group behind the attack claims that all the credentials were scraped from exploitable devices last summer.

The group also claims that while the vulnerability that made the hack possible has been patched many of the VPN credentials are still valid.

For their part Fortinet has confirmed that they were attacked and that the hackers successfully made off with hundreds of thousands of VPN login credentials.

Half a million credentials of any sort is a serious matter but half a million VPN credentials is eye popping. If the list is exploited the groups doing so could infect a wide range of networks all around the world.

A recent Fortinet advisory had this to say about the matter:

“This incident is related to an old vulnerability resolved in May 2019. At that time, Fortinet issued a PSIRT advisory and communicated directly with customers.

And because customer security is our top priority, Fortinet subsequently issued multiple corporate blog posts detailing this issue, strongly encouraging customers to upgrade affected devices. In addition to advisories, bulletins, and direct communications, these blogs were published in August 2019, July 2020, April 2021, and again in June 2021.”

For reference the old vulnerability Fortinet is referring to is being tracked as CVE-2018-13379. A Bleeping Computer analysis of the stolen data reveals that it contains VPN credentials for 498,908 users spread over nearly 13,000 different devices.

If you have Fortinet VPN your best bet is not to take any chances. Assume that your account has been compromised and force-reset all of your users’ passwords. In addition to that take the time to do a deep dive into your logs and scan for any suspicious activity that may point to a possible intrusion.