GHSA-q66h-m87m-j2q6 Bitcoinrb Vulnerable to Command injection via RPC

• RubyGems bitcoinrb: < 1.12.0 → fixed in 1.12.0

Summary: Remote Code Execution Unsafe handling of request parameters in the RPC HTTP server results in command injection Details In lib/bitcoin/rpc/http_server.rb line 30-39, the JSON body of a POST request is parsed into `command` and `args` variables. These values are then passed to `send`, which is used to call an arbitrary class method. However, there is no validation that the provided `command` value is one of the expected RPC methods. This means that an attacker could supply a `command` value such as `system`, and then pass arbitrary system commands into the `args` parameter and achieve remote code execution. PoC 1. Start the RPC server 2. Send a request to the RPC server as so: ``` curl -X POST http://127.0.0.1:18443 -H 'Content-Type: application/json' \ -d '{"method":"eval","params":["File.write(\"/tmp/pwned\",\"owned\")"]}' ``` 3. Check the /tmp folder on the machine where the RPC server is being run. If a folder /pwned now exists, the vulnerability is confirmed. Impact This vulnerability would impact anyone running the RPC server. The impact is higher for those who are running it publicly exposed to the internet. Remediation Mitigating Factors: • The RPC server is part of the experimental SPV node feature, which is not documented and has very few users. • The SPV-related features may be removed in future releases. Resolution: • Added whitelist validation to allow only RPC methods defined in `RequestHandler`. • Fixed in version 1.12.0.