Notes for Computer Security

I’m not a security expert. For a long time I used the same terrible password everywhere because I’m a lazy moron. But I finally cleaned up my act. The first thing to decide is who is my adversary. I’m not trying to protect myself against government agencies nor violent crime lords. In both cases they will merely cut off my fingers until I give up my password. I’m primarily worried about hackers grabbing passwords in bulk from web sites. I’m only a tiny bit concerned about hackers getting on my machine directly.

I used Diceware to come up with a 6 word password, which is about 77 bits. I then changed a few characters randomly. Each change adds another 10 bits. I wrote it down on paper and store it in my wallet. I use this as my master password for LastPass. In addition, I use 2 factor authentication (2FA) using Google Authenticator to generate login codes (TOTP). Using LastPass I’ve generated unique, big, complex passwords for all the sites I use. Basically, there’s no way for me to log into anything without LastPass. For important sites that support it, I use 2FA with Authenticator. For these same sites I generated backup codes and stored them as secure notes in LastPass.

I use LastPass app on my iPhone 5. It’s a pain to type in my master password, so I use a PIN code to protect it. I wish that LastPass copied the iPhone’s Erase Data option: after 10 failed attempts it should delete the LastPass encrypted file. For someone to get this data, they need to get through the iPhone PIN and the LastPass PIN. I should use a password instead of a simple 4 digit passcode on the iPhone.

On my Mac I use the LastPass browser extension and the LastPass desktop app. Neither of these are password protected, and I turned off 2FA. I can set them to auto logoff after a timeout, but then I have to type in my master password every time. I’d prefer to enter a PIN code, which falls back to the master password after 3 failures. Instead, the only thing protecting my computer is a terrible account password. I should change that. Again, I wish the Mac supported a PIN for quick login and a backup password. Or 2FA somehow.

My laptop is encrypted with FileVault. Backups run by Crashplan are encrypted with my account password. The spare computer holding my backups has a terrible password and is not encrypted. I think that’s all ok so far. Though I’m not sure why security people trust FileVault and not Microsoft’s BitLocker.

For some inexplicable reason, none of my banks — the most important sites to protect!! — support 2FA. Etrade does support Symantec’s VIP Access app. However, why don’t they support Authenticator or just plain TOTP? Also, if I turn it on then I can’t use Quicken or Mint.com. It should support app-specific passwords that have read-only access to my accounts. This is a serious weakness.

I really don’t like Google Authenticator. I’d prefer to use Authy. It’s easier to use and it stores an encrypted backup of your codes to load onto another phone. But I don’t quite understand how they ensure the other phone is under my control. Could a hacker fool them into copying my Authy data to another device? Plus, their desktop app doesn’t feel like it’s in the spirit of 2FA.

LastPass is the center of my security universe. If someone breaks into LastPass, as they did recently, I’m pretty much screwed. Other people use KeePass because they have control over the encrypted DB. But it isn’t easy to use like LastPass. It’s a tradeoff I’m willing to make. I’d like to use Yubikey when LastPass supports U2F. This would prevent phishing attacks. However, I’m still vulnerable if someone figures out how to write a page that extracts data from the browser extension. Also, I’m not comfortable with their account recovery schemes. I think there’s a way for an attacker to turn off 2FA and then force recovery using a OTP stored in your browser. This would work if they have your laptop, including email access. I should fix this somehow.

Overall this setup is moderately secure, but the NSA could break it in a jiffy.

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