Hackers broke into two FreeBSD project servers using an SSH authentication key* and login credentials that appear to have been stolen from a developer, it has emerged.
Developers behind the venerable open-source operating system have launched an investigation and have taken a few of the servers offline during their probe, but early indications are that the damage might have been far worse.
None of the so-called base repositories - stores of core components such as the kernel, system libraries, compiler and daemons (server software) - were hit. And only servers hosting source code for third-party packages were exposed by the attack, which was detected on 11 November and announced on Saturday, 17 November, following a preliminary investigation. The intrusion itself may have happened as far back as 19 September.
On Sunday 11 of November, an intrusion was detected on two machines within the FreeBSD.org cluster. The affected machines were taken offline for analysis. Additionally, a large portion of the remaining infrastructure machines were also taken offline as a precaution.
We have found no evidence of any modifications that would put any end user at risk. However, we do urge all users to read the report available at http://www.freebsd.org/news/2012-compromise.html and decide on any required actions themselves. We will continue to update that page as further information becomes known. We do not currently believe users have been affected given current forensic analysis, but we will provide updated information if this changes.
No Trojanised packages have been uncovered, at least as yet. But FreeBSD users have been urged to carefully check third-party packages installed or updated between 19 September and 11 November nonetheless, as a precaution.
The FreeBSD.org team has promised to tighten up security, in particular by phasing out legacy services such as the distribution of FreeBSD source via CVSup, in favour of the "more robust Subversion, freebsd-update, and portsnap distribution methods". The hack was "not due to any vulnerability or code exploit within FreeBSD", according to devs.
The whole incident raises troubling questions since it seems that the unknown attackers behind the hack managed to steal both SSH (remote administration) key file and passwords from a developer. Analysis of the attack can be found in an informative blog post by Paul Ducklin of Sophos here.
Attacks on open-source repositories are far from unprecedented. Kernel.org was suspended for a month last year following a much more serious malware attack and a server compromise. A month later a breach on MySQL.com website left visitors exposed to malware.
But perhaps the most similar attack to the FreeBSD hack occurred three years ago, with a breach against the Apache Software Foundation, also facilitated by the misuse of SSH keys. ®
* SSH, or secure shell, a method of encrypted communication, is the predominant remote-access protocol for non-Windows systems. There's more on how SSH keys work in the Sophos post.