Apple updates Mac OS X after DigiNotar break-in

Apple has released security updates for its Mac OS X operating system, in a bid to mitigate the damage caused by the DigiNotar break-in.

Security Update 2011-005 for the Snow Leopard and Lion versions of the OS was made available on Friday. It ensures that DigiNotar certificates are not trusted, as the break-in resulted in fraudulent certificates being issued for malicious purposes.

The update removes DigiNotar from the lists of trusted root certificates and extended validation (EV) certificate authorities, and configures default system trust settings "so that DigiNotar's certificates, including those issued by other authorities, are not trusted", a description of the update said.

Digital certificates are issued by trusted organisations such as DigiNotar so that web services can prove they are who they say they are, rather than a malicious site posing as, for example, Gmail. The secure socket layer (SSL) certificates prove that legitimacy when secure HTTPS connections are made.

The DigiNotar attack became apparent at the end of August, when Google reported man-in-the-middle attacks that were based on a fraudulent SSL certificate issued by the Dutch company. The certificate was used to try to intercept people's communications with Google's services, and one motive seems to have been spying on Iranians in particular.

False SSL certificates were also found for the UK's Secret Intelligence Service, the CIA and Mossad, as well as for Facebook, Skype, Twitter and the Tor project.

The identity of the hacker or hackers who broke into DigiNotar is not known for sure, although those claiming responsibility have made a link to similar attacks in March.