CAT | Security Breaches
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.
A vulnerability in LIFX WiFi enabled light bulbs allowed researchers at Context Information Security to control the lights and access information about the local network setup.
The whole “Internet of Things” trend is introducing all kinds of new vulnerabilities. Because these devices tend to be cheap, don’t feel like tech, and don’t expose much user interface, users are unlikely to secure, patch, or otherwise maintain them.
As these devices proliferate in our networks, we will be introducing ever more largely invisible vulnerabilities, usually without any thought to the consequences.