For security reasons new builds of Microsoft Office for Microsoft 365 on Windows block activation of Flash, Silverlight, and Shockwave controls. Most users won't be impacted, but for some users this may cause one of the following issues.

1. Ms Silverlight Download
2. Ms Silverlight For Mac
3. Ms Silverlight For Windows

MS-ISAC ADVISORY NUMBER:

• RECOMMENDED: Use Silverlight in the 32-bit Internet Explorer process on x64 systems. Most browser plug-ins (including Silverlight, Flash, Java and almost all ActiveX controls) only work in 32-bit browsers currently.
• MS-ISAC ADVISORY NUMBER: 2016-135 DATE(S) ISSUED: OVERVIEW: A vulnerability has been discovered in Microsoft Silverlight, which could allow for remote code execution. Microsoft Silverlight is a media application for browsers on Microsoft Windows and Apple Mac OS technologies.

Ms Silverlight Download

DATE(S) ISSUED:

OVERVIEW:

A vulnerability has been discovered in Microsoft Silverlight, which could allow for remote code execution. Microsoft Silverlight is a media application for browsers on Microsoft Windows and Apple Mac OS technologies. Successful exploitation of this vulnerability could result in an attacker gaining the same privileges as the logged on user. Depending on the privileges associated with the user, an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

THREAT INTELLIGENCE:

There are currently no reports of these vulnerabilities being exploited in the wild.

SYSTEMS AFFECTED:

• Microsoft Silverlight 5 prior to version 5.1.50709.0
• Microsoft Silverlight 5 Developer Runtime prior to version 5.1.50709.0

RISK:

Government:

• Large and medium government entities: HIGH
• Small government entities: MEDIUM

Businesses:

Ms Silverlight For Mac

• Large and medium business entities: HIGH
• Small business entities: MEDIUM

Home Users:

TECHNICAL SUMMARY:

One vulnerability has been discovered in Microsoft Silverlight, which could allow for remote code execution (CVE-2016-3367). This vulnerability exists when Microsoft Silverlight improperly allows applications to access objects in memory. To exploit the vulnerability, an attacker could host a website that contains a specially crafted Silverlight application and then convince a user to visit the compromised website, typically by enticing them to click a link in an email or instant message.

Successful exploitation could result in an attacker gaining the same privileges as the logged on user. Depending on the privileges associated with the user, an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

RECOMMENDATIONS:

We recommend the following actions be taken:

Apply appropriate patches provided by Microsoft to vulnerable systems immediately after appropriate testing.
Run all software as a non-privileged user (one without administrative privileges) to diminish the effects of a successful attack.
Remind users not to visit un-trusted websites or follow links provided by unknown or un-trusted sources.
Inform and educate users regarding the threats posed by hypertext links contained in emails or attachments especially from un-trusted sources.

REFERENCES:

Ms Silverlight For Windows