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Tor software updated after hackers crack into systems
Miscreants remain anonymous
Privacy-conscious users of the Tor anonymiser network have been urged to upgrade their software, following the discovery of a security breach.
Two of seven directory authorities and a metrics data server were compromised in a hack discovered earlier this month, Tor developer Roger Dingledine explains. The three servers were taken offline and refurbished following the hack.
Fresh identity keys for the two directory authorities hit by the hack were created during the refurbishment process. Users should therefore update to either Tor version 0.2.1.22 or 0.2.2.7-alpha, so that they can use the refurbished servers as conduits for sensitive traffic.
Project volunteers have taken steps to harden systems and prevent a repetition of the hack, the significance of which has been downplayed. Attackers reportedly used Tor's systems solely as a launchpad for other attacks, without realising that the same servers also hosted Tor code depositories. These were left unaffected by the breach.
"It appears the attackers didn't realize what they broke into - just that they had found some servers with lots of bandwidth," Dingledine explains. "The attackers set up some ssh keys and proceeded to use the three servers for launching other attacks."
Neither was the attack severe enough for the unidentified attackers to match up users to their destinations. Nor did it affect the Tor source code.
More details on the attack can be found in an FAQ posted by Dingledine here.
Previous security flaps around Tor have involved eavesdropping at exit nodes, an inherent limitation of the system. The latest security problems is less serious but sill merits attention. ®