CVE-2016-2166: Apache Qpid Proton python binding silently ignores request for 'amqps' if SSL/TLS not supported Mar 23 2016 02:22PM
Ken Giusti (kgiusti redhat com)

Apache Software Foundation - Security Advisory

Apache Qpid Proton python binding silently ignores request for
'amqps' if SSL/TLS not supported.

CVE-2016-2166 CVS: 5.7

Severity: Moderate


The Apache Software Foundation

Versions Affected:

Apache Qpid Proton python API starting at 0.9 up to and including
version 0.12.0.


Messaging applications using the Proton Python API to provision an
SSL/TLS encrypted TCP connection may actually instantiate a
non-encrypted connection without notice if SSL support is unavailable.
This will result in all messages being sent in the clear without the
knowledge of the user.

This issue affects those applications that use the Proton Reactor
Python API to create SSL/TLS connections. Specifically the
proton.reactor.Connector, proton.reactor.Container, and
proton.utils.BlockingConnection classes are vulnerable. These classes
can create an unencrypted connections if the "amqps://" URL prefix is

The issue only occurs if the installed Proton libraries do not support
SSL. This would be the case if the libraries were built without SSL
support or the necessary SSL libraries are not present on the system
(e.g. OpenSSL in the case of *nix).

To check whether or not the Python API provides SSL support, use the
following console command:

python -c "import proton; print('%s' % 'SSL present' if proton.SSL.present() else 'SSL NOT AVAILBLE')"

In addition, the issue can only occur if both ends of the connection
connect without SSL. This would be the case if the vulnerability is
active on both ends of the connection, or the non-affected endpoint
allows cleartext connections.


Proton release 0.12.1 resolves this issue by raising an SSLUnavailable
exception when SSL is not available and a SSL/TLS connection is
requested via the "amqps://" URL prefix.

The 0.12.1 release can be downloaded via the website:


A patch is also available:


Common Vulnerability Score information:

This issue facilitates a Man-in-the-middle attack. All communications
passing over the connection can be snooped and/or modified by a third


This issue was discovered by M. Farrellee from Red Hat.

Common Vulnerability Score information:

CVSS Base Score 5.8
Impact Subscore 4.9
Exploitability Subscore 8.6
CVSS Temporal Score 5
CVSS Environmental Score 5.7
Modified Impact Subscore 6
Overall CVSS Score 5.7

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