I've been reading about the 'Heartbleed' SSL/TLS bug (CVE-2014-0160) and it is alarming. Are my communications still secure? Are there any steps I should do to protect my security?
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2 Answers
The problem is very serious. One should not underestimate the potential security risk of this problem. The heartbleed SSL bug was there since December of 2011 till April 7 2014. Even now it is not practical to update everything at once. Please note that Tor people carefully state that these are their first thoughts. It will take a long time to fully understand the ramification of this problem. Also please note that Tor is a system containing many parts. It include the Clients, the relays and bridges, Directory authorities, Hidden services, and others. The weakest link in the system will cause problem for the whole system. Until the full ramification of this problem is known one should be very carefull. Below, please find the initial statement by Tor people:
Here are our first thoughts on what Tor components are affected:
Clients: The browser part of Tor Browser shouldn't be affected, since it uses libnss rather than openssl. But the Tor client part is: Tor clients could possibly be induced to send sensitive information like "what sites you visited in this session" to your entry guards. If you're using TBB we'll have new bundles out shortly; if you're using your operating system's Tor package you should get a new OpenSSL package and then be sure to manually restart your Tor.
Relays and bridges: Tor relays and bridges could maybe be made to leak their medium-term onion keys (rotated once a week), or their long-term relay identity keys. An attacker who has your relay identity key can publish a new relay descriptor indicating that you're at a new location (not a particularly useful attack). An attacker who has your relay identity key, has your onion key, and can intercept traffic flows to your IP address can impersonate your relay (but remember that Tor's multi-hop design means that attacking just one relay in the client's path is not very useful). In any case, best practice would be to update your OpenSSL package, discard all the files in keys/ in your DataDirectory, and restart your Tor to generate new keys. (You will need to update your MyFamily torrc lines if you run multiple relays.)
Hidden services: Tor hidden services might leak their long-term hidden service identity keys to their guard relays. Like the last big OpenSSL bug, this shouldn't allow an attacker to identify the location of the hidden service, but an attacker who knows the hidden service identity key can impersonate the hidden service. Best practice would be to move to a new hidden-service address at your convenience.
Directory authorities: In addition to the keys listed in the "relays and bridges" section above, Tor directory authorities might leak their medium-term authority signing keys. Once you've updated your OpenSSL package, you should generate a new signing key. Long-term directory authority identity keys are offline so should not be affected (whew). More tricky is that clients have your relay identity key hard-coded, so please don't rotate that yet. We'll see how this unfolds and try to think of a good solution there.
Tails is still tracking Debian oldstable, so it should not be affected by this bug.
Orbot looks vulnerable; they have some new packages available for testing.
The webservers in the https://www.torproject.org/ rotation needed (and got) upgrades. Maybe we'll need to throw away our torproject SSL web cert and get a new one too
Found the answer in the official Tor Blog. From the article:
"Tor Browser shouldn't be affected, since it uses libnss rather than openssl. But Tor clients could possibly be induced to send sensitive information like "what sites you visited in this session" to your entry guards. If you're using TBB we'll have new bundles out shortly; if you're using your operating system's Tor package you should get a new OpenSSL package and then be sure to manually restart your Tor."
Keep in mind that this bug transparently forced a leak of server memory. This means that any data stored by the server (e.g. your password on said server) is likely compromised. Also, during the time the Heartbleed vulnerability exists on a server it is sometimes possible to obtain the data necessary for SSL certificate forgery - so even a presumed secure (i.e. using https) connection could actually be with a malicious third party.
Once a previously affected server has been secured then each user should reset their password for that site.