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Wednesday, March 29, 2017

How to use secrets

From time to time you heard about how someone's site has been compromised and customer's personal information has been leaked. For example, Target Got Hacked Hard.

What can you do? Good passwords is a start.

First is understanding how do we choose a password.

If the password can be 10 characters with uppercase, lowercase, digits and symbols it could be (26 + 26 + 10 + 32) to the power of 10 or 5.386151140948997e19 different possible passwords. Even if you could attempt thousands of password attempts a second, it would take you eons to be able to crack this. Most systems will also throttle how many attempts to you can make per minute.

A good hacker won't attempt all possible combinations. They would use a dictionary to restrict the attempts to known password combinations. They might be able to reduce the number of different possible passwords to something they could attempt within a year. So systems will often request you change your password every 90 days.

Additionally, if the system allows for more characters (password length of 20 or 30 characters) just adding a few characters will make it exponentially harder to crack.

So don't use known patterns (dictionary attack), make your password as long as possible, change it every few months. The change should also be significant.

Now maybe you have to type the password into a mobile device and a really long, complicated password is going to be a bother. So you end up shortening it. Also, if you password is something like "CBVcP3Zj/i}3mK,xUL7U", you are never going to remember that. You will be tempted to make it shorter, easy to remember and you won't want to change it too often. So something like "!Passw0rd!" seems like a good password. It has uppercase, lowercase, digit, symbols, it is easy to remember, it is 10 characters long. However, it is easy to guess. A hacker will DEFINITELY have this in their dictionary.

What about changing the password? If your password was "My!S3cr3t!Passw0rd!" and I changed it to "My!S3cr3t!Passw0rd!01", next I used "My!S3cr3t!Passw0rd!02", someone will guess this with a dictionary attack.

Additionally, it used to be that a 6 character password wasn't crackable by brute force. As computers got faster we needed 8 character passwords. Today it seems that companies are recommending 12 character passwords. So if you want to be safe, you should use at least 20 character passwords.

So REALLY the password of "CBVcP3Zj/i}3mK,xUL7U" is what we want to use. That said, I've known security staff walk around the office looking for post-it notes. People will write their password on a post-it note and stick the note to a monitor. A lot of time, systems are hacked because of an insider getting a password which was written down. When I first got into computers, a high school teacher wrote the password to the system on a sheet in his desk. I know this because students would see him looking in his desk then logging in the system. One of the students stole the password from his desk.

What about saving it on a file in the computer. That works even better for some things. I need to log into a website. I open my text file, copy the password, paste it into the website. What happens if someone gets a copy of my text file. Then they have all my passwords.

I can put them in a spreadsheet with a password or a zip file with a password. Is the password to the spreadsheet going to be "CBVcP3Zj/i}3mK,xUL7U"? And I don't write it down? Probably not.

This brings us to dynamic and static storage. If my password is in a variable or the clipboard, I can turn off my computer and it is gone. If it is stored in a text file, someone can make a copy of the file and take days trying to crack it. Hackers will sometimes get encrypted database files then spend weeks trying to crack it. This is where they get common passwords for their dictionary attacks.

What if your files are automatically backed up to iCloud or Google? Then someone might be able to intercept them and take weeks trying to crack them.

Also, how do you think I came up with "CBVcP3Zj/i}3mK,xUL7U"? The answer is a password vault program. There are a few. I use 1Password (because it works on all the devices I use). There are free options like LastPass, KeePass, Dashlane. Have a look at List of password managers for these and other options. Now you just have to pick one good, strong password to secure your vault.

Additionally, if you don't backup your vault to a cloud or let people have access to it, they cannot hack it.

Another bad practice I see people doing is saving passwords in variables. This is less for your personal passwords and more for programmers accessing enterprise sites. I might have a utility which accesses the XYZ system. If variables are set, it never asks me for a password. I might have:

export XYZ_USERNAME='abssass'
export XYZ_USERNAME='2eD$g^^nJk5wHki6Lsst4Gwr'
Now if I run the utility it will see these variable are set and use them to log in. Or I might  have something like: "http://$XYZ_USERNAME:$XYZ_PASSWORD@hostname" and so long as the variables are set, it will automatically log me into the website.

But now we are back to saving passwords in a text file. Things like export statements are saved in ~/.bash_profile on my computer.

For the team they might save the passwords in a team password manager. For example, vault by Hashicorp. To get my secrets I might execute something like:

vault read /secrets/team/storage/xyz
This might return something like:


So now I can use my UNIX/Linux skills to parse the username and password out and save them in a variable. For example:

export XYZ_PASSWORD=$(vault read /secrets/team/storage/xyz | grep xyz_password | awk '{print $2}')export XYZ_USERNAME=$(vault read /secrets/team/storage/xyz | grep xyz_username | awk '{print $2}')
This will read the information from the vault, parse out the appropriate information and save it to a variable. When I turn off my computer the variables are gone and the password isn't saved in a text file... not even encrypted.

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