Later, it emerged that the attackers had gained access to the servers at least 17 days prior to the day of discovery.

In an undated statement, the administrators said: "As noted previously, kernel.org suffered a security breach. Because of this, we have taken the time to rearchitect the site in order to improve our systems for developers and users of kernel.org.

"Thanks to all for your patience and understanding during our outage and please bear with us as we bring up the different kernel.org systems over the next few weeks. We will be writing up a report on the incident in the future."

The servers at the Linux Foundation, which discovered an unauthorised entry on September 8, are still offline.