Tor crash had slight repercussions on the bitcoin industry

Key facts:

.Onion services went offline for several hours, according to reports.

The alleged attack on Tor affected Bitcoin services such as Wasabi and Bisq.

During this weekend, errors were reported in the .onion addresses of the Tor network, as well as slight failures in some cryptocurrency services such as Bisq and Wasabi, due to alleged denial of service attacks that affected the network nodes.

Specifically, the hidden service directory nodes (Hidden Service Directories or HSDir nodes) failed, which are used to connect to .onion sites in their new address version, V3.

According to reports posted on Reddit, some dark web markets have been attacking each other in recent weeks. What were supposed to be Denial of Service (DoS) attacks between these web pages escalated to causing problems for nodes on the Tor network yesterday. None of the .onion addresses were available for several hours last Sunday.

Being Tor a tool used by cryptocurrency services to increase privacy, they were also affected by the intermittency of the connection.

As Wasabi reported earlier today, users of this privacy-focused Bitcoin wallet were subject to some delays and connection failures. But, thanks to their own configuration of this service, they managed to maintain the Internet connection via Tor.

In Wasabi, operations are routed by default through the V1 and V2 versions of Tor connections, if V3 is left disconnected. Although this connection is established directly on the open internet or clearnet, the routing is still configured through Tor, so, according to Wasabi, it does not affect, for example, the realization of a CoinJoin to mix cryptocurrencies.

To guarantee the availability of the service, the Wasabi portfolio is equipped to attend a scenario of disconnection of the exit nodes. For example, if an HSDir node goes offline, the wallet will continue to communicate with the exit node of the Tor network that this HSDir connected to, even over the Tor network. Wasabi uses Tor’s multiple connection channels when the occasion calls for it.

Wasabi Wallet.

For his part Bisq, Bitcoin’s decentralized exchange, reported problems in its service due to the same problem. As reported on Twitter, communication and messaging between the parties to the exchanges, as well as with the technical service, were seriously affected. Tor’s crash did not affect user funds or generate losses, as this technology is not used in this regard on the platform.

What was the problem?

The disconnection of the HSDir nodes, those that provide untraceable entry and exit points for their users, causes that a consensus cannot be reached on the current state of the network data directory. After a period of time, no connection to the server is possible.

On the Naked Security website we find a more detailed definition of HDirs and what their role is in this protocol.