Apple iOS 9 is out.
As usual when the left-most number changes, as here from version 8 to version 9, the download is bigger than your typical point release.
For example, when we recently updated to 8.4.1, the download was about 50MB; this time, the over-the-air (OTA) update we were offered was 1.2GB.
→ Because it’s a left-most-number update, this time we used the IPSW route, which involves downloading the full firmware image from Apple and installing it via iTunes. That way, we’ve got the firmware handy for reinstalls. We’re not going to give a how-to here, but the IPSW download is just a shade over 2GB. IPSW, as you may have guessed, comes from .ipsw, Apple’s file extension for iPhone/iPad software.
As usual, Apple’s landing page for the new release is gorgeously laid out, and filled with glowing positive comparatives: faster performance, even more productive, even more helpful (that’s Siri they’re talking about), longer battery life…
…and, most important of all from our point of view, tighter security.
That’s the reason we did the early adopter thing and updated manually without waiting for our turn in the OTA queue, which Apple typically stretches over several days to spread the load on its content delivery network.
New security features
We’ve already written about some of the changes and new features that are part of iOS 9’s tighter security:
- Default passcodes bumped from 4 digit to 6 digit PINs
- Built-in two-factor authentication (2FA).
- Changes to stop unscrupulous app vendors from finding out which competing products you are using to bombard you with crossgrade ads.
- A feature allowing extensions for mobile Safari that can do ad-blocking.
Apple itself has called out the first two of these on its own iOS 9 landing page:
Going to a 6-digit PIN doesn’t sound like much, but if you’re the sort of user who has been happy with a 4-digit PIN (we know Naked Security readers live at higher security standards – that’s only hypothetical!), the change will do no harm.
You can’t really moan at Apple for suddenly making your lock code too hard, yet a passcode 50% longer than your previous one (6 digits instead of 4) is 10,000% stronger.
→ The PIN code goes from 4 to 6 digits. Because 6 = 4 x 1.5, and 1.5 = 150%, that’s an increase of 50%. The number of combinations goes from 10,000 (104) to 1,000,000 (106). That’s 100 times as many choices, and 100 = 10,000%.
So the PIN code change is a gentle nudge in the right direction for the happy-go-lucky amongst us.
The 2FA feature is a great idea, but it’s probably a bit early for Apple to be talking about it in the present tense.
Firstly, it’s only available if every device where you use your Apple ID supports the feature, so if you are an Apple fan and have a Mac to go with your iDevice, you’re out of luck.
2FA on your Mac needs El Capitan (OS X 10.11), which isn’t available in public release yet.
Secondly, “other criteria will also be used to determine availability,” meaning that the rollout will be gradual.
Apparently, if you don’t get offered it during the post-update setup process (we weren’t), you aren’t on the list yet.
The important parts
But the really important parts of the tighter security are the ones that are as good as invisible unless you visit Apple’s HT201222 Security Updates page.
Annoyingly, when we wrote this [2015-09-17T11:00Z], that page still didn’t have product links more recent than 20 August 2015, so you need to know that the iOS 9 patches are at HT205212.
As usual, there are all sorts of vulnerabilities that have been patched, including:
- Information leakage. Access to kernel memory and memory layout from a regular app.
- Security bypass. Reset the “failed password attempts” counter to prolong passcode guessing.
- Denial of Service. Deliberately disrupt network connections belonging to other apps.
- Phishing. Send a bogus email that appears to come from a contact in the address book.
- Sniffing. Eavesdrop on TLS (secure) connections due to a certificate handling bug.
- Spoofing. Make a bogus website show up with the URL of a legitimate one.
Our favourite bug patched in the iOS 9 update was this one, nestled quietly amongst the 67 entries in the HT205212 security bug-fix list:
CoreCrypto Impact: An attacker may be able to determine a private key Description: By observing many signing or decryption attempts, an attacker may have been able to determine the RSA private key. This issue was addressed using improved encryption algorithms.
“Improved algorithms,” indeed!
Update early, update often
As usual, we recommend updating as soon as you can, for the fixes much more than the features.
And when you do the update, take the opportunity to review your security settings in general.
For example, we made sure that location services were turned off, as we wanted; and that the auto-sync features of iCloud were disabled, especially the one that pushed photos and screenshots to the cloud automatically.
Those may not be your preferences, of course, but do take the opportunity to check that your settings reflect your choices, and that you don’t finish the update with a bunch of unwanted security changes.
For advice on where to start when you review your phone’s security settings, please take a look at our popular article, Privacy and Security on Your Phone.