1 fetchmail-SA-2006-02: TLS enforcement problem/MITM attack/password exposure
3 Topics: fetchmail cannot enforce TLS
5 Author: Matthias Andree
8 Type: secret information disclosure
9 Impact: fetchmail can expose cleartext password over unsecure link
10 fetchmail may not detect man in the middle attacks
12 Credits: Isaac Wilcox (bug report, collaboration on fix)
13 CVE Name: CVE-2006-5867
14 URL: http://fetchmail.berlios.de/fetchmail-SA-2006-02.txt
15 Project URL: http://fetchmail.berlios.de/
17 Affects: fetchmail releases <= 6.3.5
18 fetchmail release candidate 6.3.6-rc1
20 Not affected: fetchmail release candidate 6.3.6-rc2
21 fetchmail release 6.3.6
23 Corrected: 2006-11-12 fetchmail 6.3.6-rc2
29 2006-11-12 internal review draft
35 fetchmail is a software package to retrieve mail from remote POP2, POP3,
36 IMAP, ETRN or ODMR servers and forward it to local SMTP, LMTP servers or
37 message delivery agents.
39 fetchmail ships with a graphical, Python/Tkinter based configuration
40 utility named "fetchmailconf" to help the user create configuration (run
41 control) files for fetchmail.
44 2. Problem description and Impact
45 =================================
47 Fetchmail has no configuration facility to enforce TLS connections.
48 Configuring --sslproto 'tls1' does not cause connection aborts if TLS is
49 not offered or the TLS handshake fails for POP3 or IMAP.
50 Even if fetchmail is forced to validate an TLS certificate by means of
51 --sslfingerprint or --sslcertck, it may expose cleartext credentials
52 over an unencrypted connection.
54 This can cause eavesdroppers to obtain the password without fetchmail's
61 Use fetchmail --ssl --sslcertck --sslproto ssl3 (or equivalent in the
62 run control file) if your upstream offers SSLv3-wrapped service on a
69 Download and install fetchmail 6.3.6 or a newer stable release from
70 fetchmail's project site at
71 <http://developer.berlios.de/project/showfiles.php?group_id=1824>.
75 A. Copyright, License and Warranty
76 ==================================
78 (C) Copyright 2006 by Matthias Andree, <matthias.andree@gmx.de>.
81 This work is licensed under the Creative Commons
82 Attribution-NonCommercial-NoDerivs German License. To view a copy of
83 this license, visit http://creativecommons.org/licenses/by-nc-nd/2.0/de/
84 or send a letter to Creative Commons; 559 Nathan Abbott Way;
85 Stanford, California 94305; USA.
87 THIS WORK IS PROVIDED FREE OF CHARGE AND WITHOUT ANY WARRANTIES.
88 Use the information herein at your own risk.
90 END OF fetchmail-SA-2006-02.txt