Warning: don't use -server or bitcoind where you web browse (v0.3.2 and lower)

Don’t use the -server or -daemon switch or run bitcoind on a machine where you use a web browser.  It opens port 8332 on 127.0.0.1, the local loopback address, and you wouldn’t think that web browsers could cross-site access it, but it is possible.

We’re working on a release soon that puts a password on the JSON-RPC interface, but until then, avoid using the -server switch, and don’t web browse on the same machine where bitcoind is running.

Update: The JSON-RPC HTTP authentication feature in 0.3.3 solves this problem.

satoshi: How many other developers do you have working with you?

Martin (another forum member and I) were talking about writing a .Net compatible library for integrating bitcoins into other programs.

Martin (another forum member and I) were talking about writing a .Net compatible library for integrating bitcoins into other programs.

I think this is a very good idea! I also think it’s important to have a PHP library since this is an important programming language for e-commerce sites. It would help a great deal in acceptance of bitcoin as a currency.

Franzl: >_> I abhor PHP, so I can’t help you there, but some day (Completely overwhelmed with projects right now, but some day…) we might write the .net library.

Don’t use the -server or -daemon switch or run bitcoind on a machine where you use a web browser.  It opens port 8332 on 127.0.0.1, the local loopback address, and you wouldn’t think that web browsers could cross-site access it, but it is possible.

This sounds like something I would not like to have happen, but what does it mean? Let’s face it, we’re ALL generating Bitcoins on everything we can get hold of. What is the potential damage, in language my Mom might understand?

SNQuote from: Satoshi Nakamoto on July 19, 2010, 4:01:38 PM UTC

Don’t use the -server or -daemon switch or run bitcoind on a machine where you use a web browser.  It opens port 8332 on 127.0.0.1, the local loopback address, and you wouldn’t think that web browsers could cross-site access it, but it is possible.

This sounds like something I would not like to have happen, but what does it mean? Let’s face it, we’re ALL generating Bitcoins on everything we can get hold of. What is the potential damage, in language my Mom might understand?

Malicious websites could have a javascript that steals all your coins.

You can still generate bitcoins, just don’t run bitcoind or bitcoin -server or bitcoin -daemon on machine that you use to browse the Web.

As sirius says, if you do you could browse to a website that empties your Bitcoin wallet without your knowledge or permission.

I’m full of dumb questions today: Are there any other conceivable problems? And would the daemon be protected of it were on a VM and/or chrooted? Thanks.

chroot: won’t protect you.

Running as a separate VM: I think will protect you. But I thought browsers wouldn’t allow XMLHTTPRequests to “localhost” from web pages fetched from the web, so my advice would be to test it. See if you can talk to the Bitcoin daemon from another VM on the same machine by running “bitcoind getinfo” or “bitcoin getinfo” on the non-bitcoin-vm.

The JSON-RPC HTTP authentication feature in 0.3.3 solves this problem.