Description of the security update for Skype for Business 2015 (Lync 2013): July 10, 2018

This security update resolves vulnerabilities in Microsoft Office that could allow remote code execution if a user opens a specially crafted Office file. To learn more about these vulnerabilities, see Microsoft Common Vulnerabilities and Exposures CVE-2018-8238 and Microsoft Common Vulnerabilities and Exposures CVE-2018-8311.

Note To apply this security update, see the prerequisites.

Be aware that the update in the Microsoft Download Center applies to the Microsoft Installer (.msi)-based edition of Office 2016. It doesn't apply to the Office 2016 Click-to-Run editions, such as Microsoft Office 365 Home (see Determining your Office version).

This security update contains the following improvements and fixes:

• Unread messages of a reopened chat room are indicated incorrectly when restarting Skype for Business 2015 (Lync 2013)
• Rate My Call privacy statement incorrectly redirects to Lync 2010 privacy statement
• You're prompted for Exchange credentials after switching network in a Skype for Business hybrid environment

Method 1: Microsoft Update

This update is available from Microsoft Update. When you turn on automatic updating, this update will be downloaded and installed automatically. For more information about how to get security updates automatically, see Windows Update: FAQ.

Method 2: Microsoft Update Catalog

To get the stand-alone package for this update, go to the Microsoft Update Catalog website.

Method 3: Microsoft Download Center

You can get the stand-alone update package through the Microsoft Download Center. Follow the installation instructions on the download page to install the update.

• Download security update 4022225 for the 32-bit version of Skype for Business 2015 (Lync 2013)
• Download security update 4022225 for the 64-bit version of Skype for Business 2015 (Lync 2013)

Prerequisites

Before you install this update, you must install Microsoft Office 2013 Service Pack 1 (KB2817430).

Additionally, to install this update, you must have the following updates installed.

Update	Download link
June 13, 2017, Lynchelploc update for Lync 2015 (Skype for Business) (3191937)	Download the 32-bit Lynchelploc update package now. Download the 64-bit Lynchelploc update package now.
June 9, 2015, update for Office 2013 (3054853) Note You don't have to apply update 3054853 if you applied the April 14, 2015, update (2889923) or the May 12, 2015, security update (3039779) for Lync 2013 (Skype for Business).	Download the 32-bit mso update package now. Download the 64-bit mso update package now.

Security update deployment information

For deployment information about this update, see security update deployment information: July 10, 2018.

Security update replacement information

This security update replaces previously released security update 4011179.

File hash information

File information

The English (United States) version of this software update installs files that have the attributes that are listed in the following tables. The dates and times for these files are listed in Coordinated Universal Time (UTC). The dates and times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and times may change when you perform certain operations on the files.