Password management tools are generally a good thing. Most of us have so many passwords now that remembering them all is difficult. While it’s tempting to use one or two passwords everywhere, this is generally viewed as a bad idea. Same goes for short or easy-to-guess passwords: bad idea.

I recommend using password management software that runs natively, on your computer. I personally use Password Corral, and have used Bruce Schneier’s Password Safe. Both store your password data on your computer, not on someone else’s computer (aka ‘the cloud’). Both are relatively basic in terms of functionality: they allow you to store all of your passwords securely; password data is encrypted and protected by a master password. They can also generate new, random passwords.

There are plenty of other password management solutions out there. Some of the most popular ones, like LastPass, provide more features and are easier to use, but there’s typically a cost. For instance, it would definitely be convenient if I could access my passwords from any computer. But if that means my password data is stored on the cloud somewhere, well, no thanks. The same goes for browser extensions that enter passwords automatically.

Which brings us to yesterday, when a Google Project Zero security researcher reported a serious vulnerability in the LastPass browser extension. With the extension enabled in your browser, a malicious web site could steal all of your passwords from the LastPass data files. Yikes. But wait, there’s more! If you’re also running the main LastPass software on your computer, a malicious web site could execute arbitrary code on your computer.

LastPass issued a response to this report, confirming the problem. Their advice to users is vague, but that’s actually a good thing: if they said too much, it could provide clues about the vulnerability to malicious hackers. But the message is clear: if you have to use LastPass, disable the Lastpass browser plugin:

Use the LastPass Vault as a launch pad – Launch sites directly from the LastPass vault. This is the safest way to access your credentials and sites until this vulnerability is resolved.

Interestingly, of the three recommendations provided, two are standard advice for anyone who uses the web: enable and use Two-Factor Authentication for sites and services that offer it; and be wary of phishing attempts.