Why you should *never* leave your Mac unattended

Posted: July 13th, 2017 | Author: | Filed under: Mac OS X | No Comments »

insecureRecently I was contracted by a local backpack company to automate changing some settings on a bunch of Mac clients. The three main parts to the script had to; clean the connect to servers window and inject a new server record in to favorites, delete all login items referencing an old file server, and find a specific keychain item, retrieve the password, and inject a new keychain item using the same password. The first two were easy enough but the keychain was interesting. Through a little bit of research I soon found that the security command could do most of what I wanted. If you issued a command like

security find-internet-password -a jordan -s file.server.local -w

It would prompt you to either allow or deny access to the item and then spit the password out on the command line. But wait a minute here, in Keychain Access.app if I want to show a password I would need the password to the computer to gain access. Not on the command line though. This was pretty interesting I thought. That means as long as I have access to the console and the machine is logged in I can extract *any* password from the login.keychain that I want.

To take this a step further I made a little bash script that dumps the login.keychain to file using security dump-keychain login.keychain then I parse the data finding all the entries that I can retrieve the password for. The script will prompt the user once for each item that it finds in the keychain and then write all the data out to a csv file in /tmp

Is this a security flaw? Well, the jury’s out on that one. Some people say YES! and some people say no. To me, it’s all just rather interesting. Try it out for yourself and you’ll see why you should never leave your machine unattended again.

Download script here

Oh btw, I am *not* a developer. Amateur scripter at best, this code takes a long time to run. Upwards 10 mins for larger keychains.