From 3671344cf6aee0773636b98414e0c89a56939645 Mon Sep 17 00:00:00 2001 From: Ingela Anderton Andin Date: Tue, 7 Nov 2017 18:34:34 +0100 Subject: ssl: Countermeasurements for Bleichenbacher attack Back ported for security reasons. Remove DTLS changes as DTLS is not at all working in OTP 18. --- lib/ssl/src/ssl_connection.erl | 21 +++++++++++++++++++-- lib/ssl/src/ssl_connection.hrl | 3 ++- lib/ssl/src/tls_connection.erl | 1 + 3 files changed, 22 insertions(+), 3 deletions(-) (limited to 'lib/ssl') diff --git a/lib/ssl/src/ssl_connection.erl b/lib/ssl/src/ssl_connection.erl index 0f0072ba34..4be59501e4 100644 --- a/lib/ssl/src/ssl_connection.erl +++ b/lib/ssl/src/ssl_connection.erl @@ -1157,8 +1157,25 @@ server_certify_and_key_exchange(State0, Connection) -> request_client_cert(State2, Connection). certify_client_key_exchange(#encrypted_premaster_secret{premaster_secret= EncPMS}, - #state{private_key = Key} = State, Connection) -> - PremasterSecret = ssl_handshake:premaster_secret(EncPMS, Key), + #state{private_key = Key, client_hello_version = {Major, Minor} = Version} = State, Connection) -> + + %% Countermeasure for Bleichenbacher attack always provide some kind of premaster secret + %% and fail handshake later.RFC 5246 section 7.4.7.1. + PremasterSecret = + try ssl_handshake:premaster_secret(EncPMS, Key) of + Secret when erlang:byte_size(Secret) == ?NUM_OF_PREMASTERSECRET_BYTES -> + case Secret of + <> -> %% Correct + Secret; + <> -> %% Version mismatch + <> + end; + _ -> %% erlang:byte_size(Secret) =/= ?NUM_OF_PREMASTERSECRET_BYTES + make_premaster_secret(Version, rsa) + catch + #alert{description = ?DECRYPT_ERROR} -> + make_premaster_secret(Version, rsa) + end, calculate_master_secret(PremasterSecret, State, Connection, certify, cipher); certify_client_key_exchange(#client_diffie_hellman_public{dh_public = ClientPublicDhKey}, diff --git a/lib/ssl/src/ssl_connection.hrl b/lib/ssl/src/ssl_connection.hrl index 9a58f2b8f7..e3abc7d4aa 100644 --- a/lib/ssl/src/ssl_connection.hrl +++ b/lib/ssl/src/ssl_connection.hrl @@ -54,7 +54,8 @@ session_cache :: db_handle(), session_cache_cb :: atom(), crl_db :: term(), - negotiated_version :: ssl_record:ssl_version(), + negotiated_version :: ssl_record:ssl_version() | 'undefined', + client_hello_version :: ssl_record:ssl_version() | 'undefined', client_certificate_requested = false :: boolean(), key_algorithm :: ssl_cipher:key_algo(), hashsign_algorithm = {undefined, undefined}, diff --git a/lib/ssl/src/tls_connection.erl b/lib/ssl/src/tls_connection.erl index 93716d31b8..5a70cf96dc 100644 --- a/lib/ssl/src/tls_connection.erl +++ b/lib/ssl/src/tls_connection.erl @@ -206,6 +206,7 @@ hello(Hello = #client_hello{client_version = ClientVersion, ssl_connection:hello({common_client_hello, Type, ServerHelloExt}, State#state{connection_states = ConnectionStates, negotiated_version = Version, + client_hello_version = ClientVersion, hashsign_algorithm = HashSign, session = Session, client_ecc = {EllipticCurves, EcPointFormats}, -- cgit v1.2.3 From 4ceea4abde1438bf9e4e209e1691449bfc93fa91 Mon Sep 17 00:00:00 2001 From: Ingela Anderton Andin Date: Wed, 22 Nov 2017 19:04:06 +0100 Subject: Prepare release --- lib/ssl/doc/src/notes.xml | 53 +++++++++++++++++++++++++++++++++++++++++++++++ lib/ssl/vsn.mk | 2 +- 2 files changed, 54 insertions(+), 1 deletion(-) (limited to 'lib/ssl') diff --git a/lib/ssl/doc/src/notes.xml b/lib/ssl/doc/src/notes.xml index 5b0b5ead20..9b58980359 100644 --- a/lib/ssl/doc/src/notes.xml +++ b/lib/ssl/doc/src/notes.xml @@ -27,6 +27,59 @@

This document describes the changes made to the SSL application.

+
SSL 7.3.3.0.1 + +
Fixed Bugs and Malfunctions + + +

An erlang TLS server configured with cipher suites + using rsa key exchange, may be vulnerable to an Adaptive + Chosen Ciphertext attack (AKA Bleichenbacher attack) + against RSA, which when exploited, may result in + plaintext recovery of encrypted messages and/or a + Man-in-the-middle (MiTM) attack, despite the attacker not + having gained access to the server’s private key + itself. CVE-2017-1000385 +

Exploiting this vulnerability to perform + plaintext recovery of encrypted messages will, in most + practical cases, allow an attacker to read the plaintext + only after the session has completed. Only TLS sessions + established using RSA key exchange are vulnerable to this + attack.

Exploiting this vulnerability to conduct + a MiTM attack requires the attacker to complete the + initial attack, which may require thousands of server + requests, during the handshake phase of the targeted + session within the window of the configured handshake + timeout. This attack may be conducted against any TLS + session using RSA signatures, but only if cipher suites + using RSA key exchange are also enabled on the server. + The limited window of opportunity, limitations in + bandwidth, and latency make this attack significantly + more difficult to execute.

RSA key exchange is + enabled by default although least prioritized if server + order is honored. For such a cipher suite to be chosen it + must also be supported by the client and probably the + only shared cipher suite.

Captured TLS sessions + encrypted with ephemeral cipher suites (DHE or ECDHE) are + not at risk for subsequent decryption due to this + vulnerability.

As a workaround if default cipher + suite configuration was used you can configure the server + to not use vulnerable suites with the ciphers option like + this:

{ciphers, [Suite || Suite <- + ssl:cipher_suites(), element(1,Suite) =/= rsa]}

+ that is your code will look somethingh like this:

+ ssl:listen(Port, [{ciphers, [Suite || Suite <- + ssl:cipher_suites(), element(1,S) =/= rsa]} | Options]). +

Thanks to Hanno Böck, Juraj Somorovsky and + Craig Young for reporting this vulnerability.

+

+ Own Id: OTP-14748

+ + +
+ +
SSL 7.3.3 diff --git a/lib/ssl/vsn.mk b/lib/ssl/vsn.mk index bd6ecebbd4..be207bcd61 100644 --- a/lib/ssl/vsn.mk +++ b/lib/ssl/vsn.mk @@ -1 +1 @@ -SSL_VSN = 7.3.3 +SSL_VSN = 7.3.3.0.1 -- cgit v1.2.3