Cisco Jabber for Windows 8.x / 9.x / 10.x / 11.0.x / 11.1.x XMPP Connection MitM STARTTLS Downgrade (cisco-sa-20151224-jab)

Medium Nessus Plugin ID 87954


The version of Cisco Jabber for Windows installed on the remote host is affected by a man-in-the-middle STARTTLS downgrade vulnerability.


The version of Cisco Jabber for Windows installed on the remote host is 8.x, 9.x, 10.x, 11.0.x, or 11.1.x prior to 11.5. It is, therefore, affected by man-in-the-middle STARTTLS downgrade vulnerability due to improper checks to ensure the Extensible Messaging and Presence Protocol (XMPP) connection is established with Transport Layer Security (TLS). A man-in-the-middle attacker can exploit this to avoid TLS negotiation, resulting in the client establishing a cleartext XMPP connection.


Upgrade to Cisco Jabber for Windows version 11.5 or later.

See Also

Plugin Details

Severity: Medium

ID: 87954

File Name: cisco_jabber_client_CSCuw87419.nasl

Version: $Revision: 1.3 $

Type: local

Agent: windows

Family: Windows

Published: 2016/01/15

Modified: 2016/04/28

Dependencies: 72727

Risk Information

Risk Factor: Medium


Base Score: 4.3

Temporal Score: 3.6

Vector: CVSS2#AV:N/AC:M/Au:N/C:P/I:N/A:N

Temporal Vector: CVSS2#E:F/RL:OF/RC:ND

Vulnerability Information

CPE: cpe:/a:cisco:jabber

Required KB Items: SMB/Cisco Jabber for Windows/Installed

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 2015/12/22

Vulnerability Publication Date: 2015/12/24

Reference Information

CVE: CVE-2015-6409

OSVDB: 132275

CISCO-SA: cisco-sa-19990111-ios-syslog

IAVB: 2016-B-0009