Bug 1216057 (CVE-2015-3420) - CVE-2015-3420 dovecot: SSL/TLS handshake failures leading to a crash of the login process.
Summary: CVE-2015-3420 dovecot: SSL/TLS handshake failures leading to a crash of the l...
Alias: CVE-2015-3420
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
Depends On: 1216059
Blocks: Embargoed1216058
TreeView+ depends on / blocked
Reported: 2015-04-28 12:26 UTC by Martin Prpič
Modified: 2021-02-17 05:21 UTC (History)
3 users (show)

Fixed In Version: dovecot 2.2.17
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2015-04-29 15:28:40 UTC

Attachments (Terms of Use)

Description Martin Prpič 2015-04-28 12:26:24 UTC
A flaw was found in the way Dovecot handled SSL handshake failures. A remote attacker could use this flaw to crash the imap-login
and pop3-login processes.

Note that only Dovecot installations accepting SSL/TLS connections that have SSLv3 disabled are vulnerable.

Additional details:


Upstream patch:


Comment 1 Martin Prpič 2015-04-28 12:28:41 UTC
Created dovecot tracking bugs for this issue:

Affects: fedora-all [bug 1216059]

Comment 2 Stefan Cornelius 2015-04-29 15:18:05 UTC
Steps to reproduce, taken from http://dovecot.org/pipermail/dovecot/2015-April/100618.html:

Add to config: ssl_protocols = !SSLv2 !SSLv3
Run: openssl s_client -ssl3 -connect localhost:995

It looks like the following commit introduced the described behaviour (not confirmed):

Our RHEL versions do not have this change. Fedora has this in the source, but I still was not able to trigger a crash. It's possible that our OpenSSL versions handle this situation more gracefully, but I didn't investigate that.

Comment 3 Stefan Cornelius 2015-04-29 15:28:40 UTC

This issue did not affect the versions of dovecot as shipped with Red Hat Enterprise Linux 5, 6, and 7.

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