Vulnerability Note VU#338736
Adobe Flash ActionScript 3 opaqueBackground use-after-free vulnerability
Original Release date: 11 Jul 2015 | Last revised: 14 Jul 2015

Overview
Adobe Flash Player contains a vulnerability in the ActionScript 3 opaqueBackground property, which can allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable system.

Description
Adobe Flash Player versions 9.0 through version 18.0.0.204 contain a use-after-free vulnerability in the AS3 opaqueBackground class. This can allow attacker-controlled memory corruption. Exploit code for this vulnerability is publicly available.
Please see Adobe Security Bulletin APSA15-04 for more details about affected Flash versions.

Impact
An attacker can execute arbitrary code in the context of the user running Flash Player. Attacks typically involve enticing a user to visit a web site containing specially-crafted Flash content, or to open a specially-crafted Microsoft Office document.

Solution
Apply an update

This issue is addressed in Flash Player Desktop 18.0.0.209. See Adobe Security Bulletin APSB15-18 for more details. Please also consider the following workarounds:
Do not run untrusted Flash content

To defend against this and other, as yet unknown vulnerabilities, disable Flash in your browser or enable Click-to-Play features. Adobe has also provided instructions for how to uninstall Flash on Windows and Mac platforms.

Use the Microsoft Enhanced Mitigation Experience Toolkit

The Microsoft Enhanced Mitigation Experience Toolkit (EMET) can be used to help prevent exploitation of this vulnerability. In particular, Attack Surface Reduction (ASR) can be configured to help restrict Microsoft Office and Internet Explorer from loading the Flash ActiveX control.

Vendor Information (Learn More)

VendorStatusDate NotifiedDate UpdatedAdobeAffected-11 Jul 2015If you are a vendor and your product is affected, let
us know.

CVSS Metrics (Learn More)

Group
Score
Vector

Base
7.5
AV:N/AC:L/Au:N/C:P/I:P/A:P

Temporal
7.5
E:H/RL:U/RC:C

Environmental
7.5
CDP:ND/TD:ND/CR:ND/IR:ND/AR:ND

References

https://helpx.adobe.com/security/products/flash-player/apsb15-18.html
https://helpx.adobe.com/security/products/flash-player/apsa15-04.html
https://www.fireeye.com/blog/threat-research/2015/07/cve-2015-5122_-_seco.html

Adobe To Fix Another Hacking Team Zero-Day


http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/display/DisplayObject.html#opaqueBackground
http://www.microsoft.com/emet

How to Enable Click-to-Play Plugins in Every Web Browser


https://helpx.adobe.com/flash-player/kb/uninstall-flash-player-windows.html
https://helpx.adobe.com/flash-player/kb/uninstall-flash-player-mac-os.html

Credit
This document was written by Will Dormann.

Other Information

CVE IDs:
CVE-2015-5122

Date Public:
05 Jul 2015

Date First Published:
11 Jul 2015

Date Last Updated:
14 Jul 2015

Document Revision:
26

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