GoBalance Flaw Lets Attackers Hijack .onion Addresses by Recovering Tor-Format Keys

Summary: Searchlight Cyber disclosed on October 8 a flaw in GoBalance, a Go rewrite of Tor's Onionbalance load balancer, in which the signing step passed only the first 32 bytes of a 64-byte Tor private key to the signer, letting anyone recover a site's master key from a single published descriptor. Between October 5 and 7, both of Dread's .onion addresses were taken over and pointed at a rival site, Conclave, and Omega confirmed on October 8 that it moved to a new address due to the GoBalance bug.
What you should know: The exposed key is the site's long-term master key, so a recovered key can sign valid records for the address far into the future, and once a descriptor has been published the leaked key cannot be pulled back - a patch alone does not undo the exposure, and affected sites must create a new .onion address and move to it.

Read the original at The Hacker News ↗