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July 24, 2011

OS X Lion Released, Brings Improved Security

As you will know by now, Apple has release Lion (OSX 10.7) to the orgasmic jubilation of Mac fans everywhere. Ok, perhaps I exaggerate, but Lion was probably the most anticipated release of OSX since Leopard. Critics will argue that the number of major new features are limited, but in my opinion it’s the refinements that make Lion a great update. And for what it’s worth, the Mac App Store update process went perfectly smoothly on my iMac.

Most importantly, however, are the security improvements that Apple have made to the OS. Leopard and Snow Leopard already had some of these features, but they were not fully developed. In Lion, it seems, many of those issues have been fixed. In fact Lion has been said by several security researchers to now offer superior security over competing operating systems. I’ve said for a while that Apple will wait until OSX is really stable before properly addressing security. It appears Lion is the start.

I’ll start off with the most user-visible security features:

  1. FileVault 2: Whereas FileVault on Snow Leopard only encrypted users’ home folders (using disk images), leaving the System and Applications vulnerable to attack, Lion now has true block-level Full Disk Encryption (XTS-AES 128 algorithm). FileVault 2 also supports full disk encryption of external USB and FireWire drives. One key new feature is Lion’s “Instant Wipe”, which will allow you to wipe the hard-drive should your computer fall into the wrong hands. Similar to iOS devices, this may tie in to the new Find My Mac functionality.
  2. Privacy Controls: Apple has sprinkled around some additional privacy controls, giving the user more say in how their data is stored or used. There’s now full control of which applications can make use of the Location Services features of OSX.
  3. Apple ID Authentication: This is an interesting feature that makes it easier for users to share content with others. Normally actions like Screen Sharing and File Sharing require the connecting user to have an account on the system. Now, you can simply add their Apple ID as an authorised account to give them selective access. It will be interesting to test how this actually works in practice.
  4. Application Sandboxing: Lion’s sandboxing capability has been greatly improved. Safari, for example, has been updated to include sandboxing, meaning that website content loads in a separate process with limited functionality. This help prevent malicious websites from gaining access to the underlying system. Apple is encouraging third party software developers to start sandboxing their applications.
  5. Full ASLR: This is a big one. Address Space Layout Randomization is a technique to make exploitation of vulnerabilities more difficult by not using fixed memory addresses for key data areas. In Snow Leopard, ASLR was half-baked and essentially broken. In Lion, it appears that Apple have finally implemented full ASLR (covering 32 and 64-bit application), although how well is yet to be fully determined. Either way this will present an additional barrier to exploits.
All in all, some significant improvements over Snow Leopard. The security push isn’t over yet, however, and I’m sure we’ll be seeing a bit more from Apple as OSX develops. This doesn’t mean vulnerabilities won’t be found in OSX, but it will make it that much harder for workable exploits to be developed. I anticipate we’ll start seeing a lot more vulndev attention being committed to OSX this year.

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