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             AUSCERT External Security Bulletin Redistribution

                               ESB-2019.2448
           Cisco Jabber for Windows DLL Preloading Vulnerability
                                4 July 2019

===========================================================================

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           Cisco Jabber for Windows
Publisher:         Cisco Systems
Operating System:  Windows
Impact/Access:     Execute Arbitrary Code/Commands -- Existing Account
Resolution:        Patch/Upgrade
CVE Names:         CVE-2019-1855  

Original Bulletin: 
   https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190703-jabber-dll

- --------------------------BEGIN INCLUDED TEXT--------------------

Cisco Jabber for Windows DLL Preloading Vulnerability

Priority:        High

Advisory ID:     cisco-sa-20190703-jabber-dll

First Published: 2019 July 3 16:00 GMT

Version 1.0:     Final

Workarounds:     No workarounds available

Cisco Bug IDs:   CSCvo55994CSCvo63008

CVE-2019-1855    

CWE-264

CVSS Score:
7.3  AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H/E:X/RL:X/RC:X

Summary

  o A vulnerability in the loading mechanism of specific dynamic link libraries
    in Cisco Jabber for Windows could allow an authenticated, local attacker to
    perform a DLL preloading attack. To exploit this vulnerability, the
    attacker would need to have valid credentials on the Windows system.

    The vulnerability is due to insufficient validation of the resources loaded
    by the application at run time. An attacker could exploit this
    vulnerability by crafting a malicious DLL file and placing it in a specific
    location on the targeted system. The malicious DLL file would execute when
    the Jabber application launches. A successful exploit could allow the
    attacker to execute arbitrary code on the target machine with the
    privileges of another user's account.

    Cisco has released software updates that address this vulnerability. There
    are no workarounds that address this vulnerability.

    This advisory is available at the following link:
    https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/
    cisco-sa-20190703-jabber-dll

Affected Products

  o Vulnerable Products

    This vulnerability affects all Cisco Jabber for Windows software releases
    prior to 12.6(0).

    Products Confirmed Not Vulnerable

    Only products listed in the Vulnerable Products section of this advisory
    are known to be affected by this vulnerability.

    Cisco has confirmed that this vulnerability does not affect the following
    Cisco products:

       Jabber for Android
       Jabber for iPhone and iPad
       Jabber for Mac

Workarounds

  o There are no workarounds that address this vulnerability.

Fixed Software

  o Cisco has released free software updates that address the vulnerability
    described in this advisory. Customers may only install and expect support
    for software versions and feature sets for which they have purchased a
    license. By installing, downloading, accessing, or otherwise using such
    software upgrades, customers agree to follow the terms of the Cisco
    software license:
    https://www.cisco.com/c/en/us/products/end-user-license-agreement.html

    Additionally, customers may only download software for which they have a
    valid license, procured from Cisco directly, or through a Cisco authorized
    reseller or partner. In most cases this will be a maintenance upgrade to
    software that was previously purchased. Free security software updates do
    not entitle customers to a new software license, additional software
    feature sets, or major revision upgrades.

    When considering software upgrades, customers are advised to regularly
    consult the advisories for Cisco products, which are available from the
    Cisco Security Advisories and Alerts page , to determine exposure and a
    complete upgrade solution.

    In all cases, customers should ensure that the devices to be upgraded
    contain sufficient memory and confirm that current hardware and software
    configurations will continue to be supported properly by the new release.
    If the information is not clear, customers are advised to contact the Cisco
    Technical Assistance Center (TAC) or their contracted maintenance
    providers.

    Customers Without Service Contracts

    Customers who purchase directly from Cisco but do not hold a Cisco service
    contract and customers who make purchases through third-party vendors but
    are unsuccessful in obtaining fixed software through their point of sale
    should obtain upgrades by contacting the Cisco TAC:
    https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html

    Customers should have the product serial number available and be prepared
    to provide the URL of this advisory as evidence of entitlement to a free
    upgrade.

    Fixed Releases

    This vulnerability is fixed in Cisco Jabber for Windows 12.6(0) and later.

Exploitation and Public Announcements

  o The Cisco Product Security Incident Response Team (PSIRT) is not aware of
    any public announcements or malicious use of the vulnerability that is
    described in this advisory.

Source

  o Cisco would like to thank security researcher "wjcsharp" for reporting this
    vulnerability.

Cisco Security Vulnerability Policy

  o To learn about Cisco security vulnerability disclosure policies and
    publications, see the Security Vulnerability Policy . This document also
    contains instructions for obtaining fixed software and receiving security
    vulnerability information from Cisco.

URL

  o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/
    cisco-sa-20190703-jabber-dll

Revision History

  o +---------+---------------------------+---------+--------+---------------+
    | Version |        Description        | Section | Status |     Date      |
    +---------+---------------------------+---------+--------+---------------+
    | 1.0     | Initial public release.   | -       | Final  | 2019-July-03  |
    +---------+---------------------------+---------+--------+---------------+

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