From 000edd9036b6aea5e6a06900ecd6c58faec665ab Mon Sep 17 00:00:00 2001 From: Eduardo Chappa Date: Thu, 18 Jun 2020 03:25:29 -0600 Subject: * Security Bug: Alpine can be configured to start a secure connection using /tls on an insecure connection. However, if the connection is PREAUTH, Alpine will not upgrade the connection to a secure connection, because a client must not issue a STARTTLS to a server that supports it in authenticated state. This makes Alpine continue to use an insecure connection with the server, exposing user data. Reported by Damian Poddebniak and Fabian Ising, from Münster University of Applied Sciences. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- imap/src/c-client/imap4r1.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'imap') diff --git a/imap/src/c-client/imap4r1.c b/imap/src/c-client/imap4r1.c index 2233da6e..4991f85e 100644 --- a/imap/src/c-client/imap4r1.c +++ b/imap/src/c-client/imap4r1.c @@ -1,7 +1,7 @@ /* * Copyright 2016-2020 Eduardo Chappa * - * Last Edited: Jan 26, 2020 Eduardo Chappa + * Last Edited: Jun 18, 2020 Eduardo Chappa * */ /* ======================================================================== @@ -891,6 +891,16 @@ MAILSTREAM *imap_open (MAILSTREAM *stream) return NIL; /* lost during greeting */ } + /* STARTTLS is not allowed in PREAUTH state */ + if (LOCAL->netstream && !strcmp (reply->key,"PREAUTH")){ + sslstart_t stls = (sslstart_t) mail_parameters (NIL,GET_SSLSTART,NIL); + if (!LOCAL->gotcapability) imap_capability (stream); + if (LOCAL->netstream + && stls && LOCAL->cap.starttls && !mb.sslflag && !mb.notlsflag && mb.tlsflag){ + mm_log("STARTTLS not allowed on PREAUTH state. Closing Connection", ERROR); + return NIL; + } + } /* if connected and not preauthenticated */ if (LOCAL->netstream && strcmp (reply->key,"PREAUTH")) { sslstart_t stls = (sslstart_t) mail_parameters (NIL,GET_SSLSTART,NIL); -- cgit v1.2.3-54-g00ecf