Vulnerability Note VU#519137

Adobe Shockwave player installs Xtras without prompting

Original Release date: 17 Dec 2012 | Last revised: 24 Jul 2014

Overview

Adobe Shockwave Player installs Xtras that are signed by Adobe or Macromedia without prompting, which can allow an attacker to target vulnerabilities in older Xtras.

Description

Adobe Macromedia Shockwave Player is software that plays active web content developed in Macromedia and Adobe Director. Shockwave Player is available as an ActiveX control for Internet Explorer and as a plug-in for other web browsers. Shockwave is also available in "Full" and "Slim" installers. The "Slim" installer provides fewer Xtras.

When a Shockwave movie attempts to use an Xtra, it will download and install it as necessary. If the Xtra is signed by Adobe or Macromedia, it will be installed automatically without any user interaction. Because the location from which Shockwave downloads the Xtra is stored in the Shockwave movie itself, this can allow an attacker to host old, vulnerable Xtras that can be installed and exploited automatically when a Shockwave movie is played.

Impact

By convincing a user to view a specially crafted Shockwave content (e.g., a web page or an HTML email message or attachment), an attacker may be able to execute arbitrary code with the privileges of the user.

Solution

We are currently unaware of a practical solution to this problem. Please consider the following workarounds:

Limit access to Director files

Restricting the handling of untrusted Director content may help mitigate this vulnerability. See Securing Your Web Browser for more information. Consider using the NoScript extension to whitelist web sites that can run Shockwave Player in Mozilla browsers such as Firefox. See the NoScript FAQ for more information.

Disable the Shockwave Player ActiveX control in Internet Explorer

The Shockwave Player ActiveX control can be disabled in Internet Explorer by setting the kill bit for the following CLSIDs:

    {166B1BCA-3F9C-11CF-8075-444553540000}
    {233C1507-6A77-46A4-9443-F871F945D258}
More information about how to set the kill bit is available in Microsoft Support Document 240797.Alternatively, the following text can be saved as a .REG file and imported to set the kill bit for this control:
    Windows Registry Editor Version 5.00

    [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\{166B1BCA-3F9C-11CF-8075-444553540000}]
    "Compatibility Flags"=dword:00000400
    [HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Internet Explorer\ActiveX Compatibility\{166B1BCA-3F9C-11CF-8075-444553540000}]
    "Compatibility Flags"=dword:00000400

    [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\{233C1507-6A77-46A4-9443-F871F945D258}]
    "Compatibility Flags"=dword:00000400
    [HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Internet Explorer\ActiveX Compatibility\{233C1507-6A77-46A4-9443-F871F945D258}]
    "Compatibility Flags"=dword:00000400
Use the Microsoft Enhanced Mitigation Experience Toolkit

The Microsoft Enhanced Mitigation Experience Toolkit (EMET) can be used to help prevent exploitation of this vulnerability. CERT/CC has created a video tutorial for setting up EMET 3.0 on Windows 7. Note that platforms that do not support ASLR, such as Windows XP and Windows Server 2003, will not receive the same level of protection that modern Windows platforms will.

Enable DEP in Microsoft Windows

Consider enabling Data Execution Prevention (DEP) in supported versions of Windows. DEP should not be treated as a complete workaround, but it can mitigate the execution of attacker-supplied code in some cases. Microsoft has published detailed technical information about DEP in Security Research & Defense blog posts "Understanding DEP as a mitigation technology" part 1 and part 2. DEP should be used in conjunction with the application of patches or other mitigations described in this document.

Note that when relying on DEP for exploit mitigation, it is important to use a system that supports Address Space Layout Randomization (ASLR) as well. ASLR is not supported by Windows XP or Windows Server 2003 or earlier. ASLR was introduced with Microsoft Windows Vista and Windows Server 2008. Please see the Microsoft SRD blog entry: On the effectiveness of DEP and ASLR for more details.

Use the "Full" Shockwave installer instead of the "Slim" one

In order for an attacker to install an older, vulnerable Xtra on a system with Shockwave, that Xtra must not already be present on the system. If you must have Shockwave installed, using the "Full" installer will cause more Xtras to be present, limiting the choices that an attacker may be able to leverage to exploit. For example, the "Slim" installer for Shockwave does not provide the Flash Xtra. An attacker could target this installation configuration by hosting an arbitrary version of the Flash Xtra that would be automatically installed and exploited upon viewing a malicious Shockwave movie. Note that as long as VU#323161 is valid, this workaround may not be effective in protecting against Flash vulnerabilities.

Vendor Information (Learn More)

VendorStatusDate NotifiedDate Updated
AdobeAffected27 Oct 201017 Dec 2012
If you are a vendor and your product is affected, let us know.

CVSS Metrics (Learn More)

Group Score Vector
Base 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N
Temporal 3.7 E:POC/RL:W/RC:C
Environmental 3.2 CDP:L/TD:M/CR:ND/IR:ND/AR:ND

References

Credit

This vulnerability was reported by Will Dormann of the CERT/CC.

This document was written by Will Dormann.

Other Information

  • CVE IDs: CVE-2012-6271
  • Date Public: 17 Dec 2012
  • Date First Published: 17 Dec 2012
  • Date Last Updated: 24 Jul 2014
  • Document Revision: 24

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