Comment 0 for bug 1662501

The default Firefox AppArmor profile (package: firefox) allows read access to all files in the system:

# in /etc/apparmor.d/usr.bin.firefox:

/**/ r

This allows browsing all directory contents on the system which violates Least Privilege Principle and allows malware to explore what's on the system (even though there are additional deny rules that protect most sensitive files, a default read all is still unacceptable).

In addition (package: apparmor) :

# in /etc/apparmor.d/abstractions/ubuntu-browsers.d/user-files:

@{HOME}/** r,
owner @{HOME}/** w,

Which allows read write to ALL USER FILES, and ALL OTHER USER FILES because default chmod on user dirs is o+rx. Granted, access to ~/.ssh is explicitly denied, but there are things like documents and other user files that should NOT be readable to Firefox at all.

This is, IMHO, a vulnerability.

The profile should allow read/write ONLY to dirs like ~/Downloads or ~/Public. In addition the above two lines that allow unconfined rw access to HOME/**, should be commented out and explained what it means to enable them if the user really wants that kind of convenience.

Modern malware is not just about code execution and modifying local or system files. Modern malware is also very much so about data and identity theft against which the current default AppArmor profile does NOT protect.

Take for example password managers like KeePassX. The default profile on ubuntu-browsers would allow unfettered access to the very much sensitive passwords database.

Sure, users can override and expand the profile with their local modifications, but this "vulnerability" is not documented or communicated to users and gives a false sense of security ("Oh, I have AppArmor profile on Firefox, I'm safe").

Unfortunately, proper security is not in the domain of casual computer usage and I understand that Ubuntu has to balance between convenience and security but IMHO it is possible to make this more secure AND at the same time inform the user where to DISABLE (rather than enable) those stricter rules.

If Ubuntu is not willing to sacrifice the convenience for PROPER security (shame on Ubuntu if that's the case), then AT THE VERY LEAST the user should be informed that the default AppArmor profile, when they install a browser, is biased toward convenience and users SHOULD take additional actions to protect themselves.

I'm sure this all applies to more than just the browsers, but browsers are my primary concern here, which are the most vulnerable component in a modern system.