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diff --git a/doc/JSON-RPC-interface.md b/doc/JSON-RPC-interface.md index 59df541567..982afd5d56 100644 --- a/doc/JSON-RPC-interface.md +++ b/doc/JSON-RPC-interface.md @@ -5,6 +5,85 @@ The headless daemon `bitcoind` has the JSON-RPC API enabled by default, the GUI option. In the GUI it is possible to execute RPC methods in the Debug Console Dialog. +## Security + +The RPC interface allows other programs to control Bitcoin Core, +including the ability to spend funds from your wallets, affect consensus +verification, read private data, and otherwise perform operations that +can cause loss of money, data, or privacy. This section suggests how +you should use and configure Bitcoin Core to reduce the risk that its +RPC interface will be abused. + +- **Securing the executable:** Anyone with physical or remote access to + the computer, container, or virtual machine running Bitcoin Core can + compromise either the whole program or just the RPC interface. This + includes being able to record any passphrases you enter for unlocking + your encrypted wallets or changing settings so that your Bitcoin Core + program tells you that certain transactions have multiple + confirmations even when they aren't part of the best block chain. For + this reason, you should not use Bitcoin Core for security sensitive + operations on systems you do not exclusively control, such as shared + computers or virtual private servers. + +- **Securing local network access:** By default, the RPC interface can + only be accessed by a client running on the same computer and only + after the client provides a valid authentication credential (username + and passphrase). Any program on your computer with access to the file + system and local network can obtain this level of access. + Additionally, other programs on your computer can attempt to provide + an RPC interface on the same port as used by Bitcoin Core in order to + trick you into revealing your authentication credentials. For this + reason, it is important to only use Bitcoin Core for + security-sensitive operations on a computer whose other programs you + trust. + +- **Securing remote network access:** You may optionally allow other + computers to remotely control Bitcoin Core by setting the `rpcallowip` + and `rpcbind` configuration parameters. These settings are only meant + for enabling connections over secure private networks or connections + that have been otherwise secured (e.g. using a VPN or port forwarding + with SSH or stunnel). **Do not enable RPC connections over the public + Internet.** Although Bitcoin Core's RPC interface does use + authentication, it does not use encryption, so your login credentials + are sent as clear text that can be read by anyone on your network + path. Additionally, the RPC interface has not been hardened to + withstand arbitrary Internet traffic, so changing the above settings + to expose it to the Internet (even using something like a Tor hidden + service) could expose you to unconsidered vulnerabilities. See + `bitcoind -help` for more information about these settings and other + settings described in this document. + + Related, if you use Bitcoin Core inside a Docker container, you may + need to expose the RPC port to the host system. The default way to + do this in Docker also exposes the port to the public Internet. + Instead, expose it only on the host system's localhost, for example: + `-p 127.0.0.1:8332:8332` + +- **Secure authentication:** By default, Bitcoin Core generates unique + login credentials each time it restarts and puts them into a file + readable only by the user that started Bitcoin Core, allowing any of + that user's RPC clients with read access to the file to login + automatically. The file is `.cookie` in the Bitcoin Core + configuration directory, and using these credentials is the preferred + RPC authentication method. If you need to generate static login + credentials for your programs, you can use the script in the + `share/rpcauth` directory in the Bitcoin Core source tree. As a final + fallback, you can directly use manually-chosen `rpcuser` and + `rpcpassword` configuration parameters---but you must ensure that you + choose a strong and unique passphrase (and still don't use insecure + networks, as mentioned above). + +- **Secure string handling:** The RPC interface does not guarantee any + escaping of data beyond what's necessary to encode it as JSON, + although it does usually provide serialized data using a hex + representation of the bytes. If you use RPC data in your programs or + provide its data to other programs, you must ensure any problem + strings are properly escaped. For example, multiple websites have + been manipulated because they displayed decoded hex strings that + included HTML `<script>` tags. For this reason, and other + non-security reasons, it is recommended to display all serialized data + in hex form only. + ## RPC consistency guarantees State that can be queried via RPCs is guaranteed to be at least up-to-date with |