Disable SSLv3 (in favor of TLS) for the RPC client and server.

TLS is subject to downgrade attacks when SSLv3 is available, and
 SSLv3 has vulnerabilities.

The popular solution is to disable SSLv3. On the web this breaks
 some tiny number of very old clients. While Bitcoin RPC shouldn't
 be exposed to the open Internet, it also shouldn't be exposed to
 really old SSL implementations, so it shouldn't be a major issue
 for us to disable SSLv3.

There is more information on the downgrade attacks and disabling
 SSLv3 at https://disablessl3.com/ .

2 files changed, 2 insertions, 2 deletions

diff --git a/src/bitcoin-cli.cpp b/src/bitcoin-cli.cpp
index 1b638e99e9..ea349b197e 100644
--- a/src/bitcoin-cli.cpp
+++ b/src/bitcoin-cli.cpp
@@ -110,7 +110,7 @@ Object CallRPC(const string& strMethod, const Array& params)
     bool fUseSSL = GetBoolArg("-rpcssl", false);
     asio::io_service io_service;
     ssl::context context(io_service, ssl::context::sslv23);
-    context.set_options(ssl::context::no_sslv2);
+    context.set_options(ssl::context::no_sslv2 | ssl::context::no_sslv3);
     asio::ssl::stream<asio::ip::tcp::socket> sslStream(io_service, context);
     SSLIOStreamDevice<asio::ip::tcp> d(sslStream, fUseSSL);
     iostreams::stream< SSLIOStreamDevice<asio::ip::tcp> > stream(d);
diff --git a/src/rpcserver.cpp b/src/rpcserver.cpp
index 90695611f2..252b0866a2 100644
--- a/src/rpcserver.cpp
+++ b/src/rpcserver.cpp
@@ -597,7 +597,7 @@ void StartRPCThreads()
 
     if (fUseSSL)
     {
-        rpc_ssl_context->set_options(ssl::context::no_sslv2);
+        rpc_ssl_context->set_options(ssl::context::no_sslv2 | ssl::context::no_sslv3);
 
         filesystem::path pathCertFile(GetArg("-rpcsslcertificatechainfile", "server.cert"));
         if (!pathCertFile.is_complete()) pathCertFile = filesystem::path(GetDataDir()) / pathCertFile;