Mac OS X Security Vulnerability setuid root applications leave root shell open for hackers
Operating System: Max OS X Version Affected: up to 10.1
Security Risk: High
Remote: No
Fixed: 10.20.2001 see below
About
Mac OS X over the past few months have started to spout security concerns, this being one of the first most publicized attacks on the operating system. Once logged into Mac OS X, any user can obtain a root shell by executing a few simple applications in specific order.
Mac OS X is already on computers in every sort of nature, even after the administrator sets up multiple accounts with specific privileges keeping the user from hacking a root prompt is not that simple.
Take a look at the vulnerability, afterwards we will describe how this actually happens.
Vulnerability
1. Open up the Terminal.app
2. Quit it.
3. Open up NetInfo Manager (leave it in the foreground)
4. Open up Terminal.app from the *RECENT ITEMS* list in the Apple Menu.
You will now see a terminal logged in as root shown with the # prompt, this is because the application NetInfo Manager has root privileges and told to be executed by the user with the systems allowance. There is a misinterpretation of which user is logged in because a root privileged program is running, thus by opening the Terminal.app from the recent items you are brought to a root prompt.
Picture this: You walk through security with a secret agent, the officer does a ID check to see if the agent have high enough status to carry a weapon, he lets you and the agent in with the understanding that only the agent can carry or use the weapon. Once you are in you take the weapon from the agent, you do this because the person associated with you have the rights, suddenly you have more power. You shouldn’t because the access was given to the one agent.
Apple should and will with the next update disable the security risk of gaining root privileges from other programs. Bookmark this page to see updates and user responses.
NetInfo Manager is just one of the setuid applications on Mac OS X to find all files with setuid permissions execute this command:
sudo find / -perm -4000 -user root -print | more
Discussion + Fixes
FIX! Apple has released a fix for this security issue, to fix the vulnerability simply launch Apple’s Software Update utility and start the download or download the fixes file here . Once download is complete and update is finished you must restart for changes to take effect. This wil fix the security issue discussed within this document.
It is said that this apparently is the case with all setuid root applications… Not good…. Submitted by Eric.C
You can temporarily patch this problem by going into a command shell and change the permissions of the Setuid applications so that only root account and admin group have privileges to execute the program. Do this by using the sudo command and chmod 770 setuid.app. This takes away all privileges to any user that isn’t root or admin. – will@pnl
Another user suggests keeping the password protected screensaver activated when away from the computer, this will help to stop users from accessing the computer yet fails to stop users with accounts from obtaining root privileges.
