diff --git a/changes/pathsel-BUGGY-a b/changes/pathsel-BUGGY-a index cad2af5c0d..2e642c7953 100644 --- a/changes/pathsel-BUGGY-a +++ b/changes/pathsel-BUGGY-a @@ -3,10 +3,12 @@ - Try to leak less information about what relays a client is choosing to a side-channel attacker. Previously, a Tor client would stop iterating through the list of available relays as - soon as it had chosen one, thus leaking information about which - relays it picked for a circuit to a timing attack. (Tor is - likely to still leak information about which relays it has - chosen for a circuit to other processes on the same computer, - through e.g. which cache lines it loads while building the - circuit.) - + soon as it had chosen one, thus finishing a little earlier + when it picked a router earlier in the list. If an attacker + can recover this timing information (nontrivial but not + proven to be impossible), they could learn some coarse- + grained information about which relays a client was picking + (middle nodes in particular are likelier to be affected than + exits). The timing attack might be mitigated by other factors + (see bug #6537 for some discussion), but it's best not to + take chances. Fixes bug 6537; bugfix on 0.0.8rc1.