Arch Linux: ASA-201410-13 High: ejabberd Encryption Circumvention

The package ejabberd before version 14.07-2 allows clients to connect with an unencrypted connection even if starttls_required is set.

Arch Linux Security Advisory ASA-201410-13
=========================================
Severity: High
Date    : 2014-10-27
CVE-ID  : CVE-2014-8760
Package : ejabberd
Type    : circumvention of encryption
Remote  : No
Link    : https://wiki.archlinux.org/title/CVE-2014

Summary
======
The package ejabberd before version 14.07-2 allows clients to connect
with an unencrypted connection even if starttls_required is set.

Resolution
=========
Upgrade to 14.07-2.

# pacman -Syu "ejabberd>=14.07-2"

The problems have been fixed upstream [0] but no release version is
available yet.

Workaround
=========
Disable compression ('zlib' in c2s configuration) and find affected
users with:

# ejabberdctl connected_users_info | grep 'c2s_compressed\s'

You may kick affected user sessions and they should be able to reconnect
with encryption and without compression.

Description
==========
It was discovered that ejabberd does not enforce the starttls_required
setting when compression is used, which causes clients to unexpectedly
establish connections without encryption.

Impact
=====
A local user can unexpectedly connect without any encryption and send
sensitive information in plaintext to the server even if encryption was
set as required.

References
=========
[0] https://github.com/processone/ejabberd/commit/7bdc115
https://www.cve.org/CVERecord?id=CVE-2014-8760
https://bugs.archlinux.org/task/42541