CAT | Security Breaches
The Internet is on fire with discussions of the recent release of stolen nude photos of over 100 female celebrities. This is a massive invasion of their privacy, and it says something sad about our society that there is an active market for such pictures. While this particular attack was against the famous, most of us have information in the cloud that we would like to stay secret.
While there is not a definitive explanation of the breach the current consensus is that it was probably caused by a vulnerability in Apple’s “Find My iPhone” feature. Apparently the API interface to this service did not check for multiple password failures, a standard security practice. This allowed attackers to test effectively unlimited numbers of passwords for each of the accounts they wanted to access.
Because most people use relatively weak passwords, this attack is quite effective. Once they gained access to the accounts, they could sync down photos or any other information stored in iCloud.
Of course, the first rule of secrecy is: If it does not exist, it can’t be discovered.
If you do want to create something that you would be pained to see released publicly, then make sure you keep close control of it. Store it locally, and encrypted.
Wherever you keep it, make sure it has a strong password. Advice for strong passwords has changed over time because of the increasing speed of computers. It used to be that fancy pneumonics would do the trick but now the fundamental truth is: if you can remember it, it is too weak.
This is particularly true because you need to be using completely different passwords for every website. Changing a good password in a simple obvious way for every website is obvious. It might prevent brute force attacks but if some other attack gives access to your password, the attacker will be able to easily guess your password on all other websites.
You need to be using a password manager like 1Password (Mac), LastPass, Dashlane, etc. Let the password manager generate your passwords for you. This is what a good password should look like: wL?7mpEyfpqs#kt9ZKVvR
Obviously I am never going to remember that, but I don’t try. I have one good password that I have taken the time to memorize, and it unlocks the password manager which has everything else.
UPDATE: There appears to be some question about whether this vulnerability is actually to blame.
This article describes a clever attack against Secret, the “anonymous” secret sharing app.
Their technique allows the attacker to isolate just a single target, so any posts seen are known to be from them. The company is working on detecting and preventing this attack, but it is a hard problem.
In general, any anonymity system needs to blend the activity of a number of users so that any observed activity could have originated from any of them. For effective anonymity the number needs to be large. Just pulling from the friends in my address book who also use Secret is way too small a group.
On Friday I was asked to come on The Social Network Show to talk about the fact and questions surrounding the theft of over 1 Billion passwords.
Tor just announced that they have detected and blocked an attack that may have allowed hidden services and possibly users to be de-anonymized.
It looks like this may be connected to the recently canceled BlackHat talk on Tor vulnerabilities. One hopes so, otherwise the attack may have been more hostile than simple research.
Tor is releasing updated server and client code to patch the vulnerability used in this attack. This shows once again one of the key architectural weaknesses in Tor, the distributed volunteer infrastructure. On the one hand, it means that you are not putting all of your trust in one entity. On the other hand, you really don’t know who you are trusting, and anyone could be running the nodes you are using. Many groups hostile to your interests would have good reason to run Tor nodes and to try to break your anonymity.
The announcement from Tor is linked below.
On July 2, Google engineers discovered unauthorized certificates for Google domains in circulation. They had been issued by the National Informatics Center in India. They are a trusted sub-authority under the Indian Controller of Certifying Authorities (CCA). They in turn are part of the Microsoft Root Store of certificates, so just about any program running on Windows, including Explorer and Chrome, will trust the unauthorized certificates.
The power of this attack is that the holder of the private key to the certificate can impersonate secure Google servers. Your browser would not report any security alerts because the certificate is “properly” signed and trusted within the built in trust hierarchy.
Firefox does not have the CCA in its root certificate list and so is not affected. Likewise Mac OS, iOS, Android, and Chrome OS are safe from this particular incident as well.
It is not known exactly why these certificates were issued, but the obvious use would be national surveillance.
While this attack seems to be targeted to India and only impacts the Microsoft ecosystem, the larger problem is much more general. There is a long list of trusted certificate authorities, which in turn delegate trust to a vast number of sub-authorities, any of whom can trivially create certificates for any domain which would be trusted by your computer.
In this case the attack was detected quickly, but if it had been very narrowly targeted detection would have been very unlikely and monitoring could have continued over very long periods.
As an end user, you can install Certificate Patrol in Firefox to automatically detect when a website’s certificate is changed. This would detect this kind of attack.
On Chrome you should enable “Check for server certificate revocation” in advanced settings. That will at least allow quick protection once a certificate is compromised.
Update: Microsoft has issued an emergency patch removing trust from the compromised authority.