Adobe Secure Software Engineering Team (ASSET) Blog

Today we released Security Bulletin APSB12-08 along with corresponding updates for Adobe Reader and Acrobat. We’d like to highlight a few changes we are making with today’s releases.

Rendering Flash (SWF) Content in Adobe Reader and Acrobat 9.5.1

First off, starting with the Adobe Reader and Acrobat 9.5.1 updates, Adobe Reader and Acrobat 9.x on Windows and Macintosh will use the Adobe Flash Player plugin version installed on the user’s system (rather than the Authplay component that ships with Adobe Reader and Acrobat) to render any Flash (SWF) content contained in PDF files. We added an Application Programming Interface (API) to both Adobe Reader/Acrobat and Flash Player to allow Adobe Reader/Acrobat to communicate directly with a Netscape Plugin Application Programming Interface (NPAPI) version of Flash Player installed on the user’s system. From a security perspective, this means that Adobe Reader/Acrobat 9.x users will no longer have to update Adobe Reader/Acrobat each time we make available an update for Flash Player. This will be particularly beneficial to customers in managed environments because fewer updates help reduce the overhead for IT administration.

If Adobe Reader or Acrobat 9.5.1 is installed on a system that does not have the NPAPI version of Flash Player installed and the user opens a PDF file that includes Flash (SWF) content, a dialog will prompt the user to download and install the latest Flash Player. (Browsers such as Firefox, Opera and Safari use the NPAPI version of Flash Player as opposed to the ActiveX version of Flash Player used by Internet Explorer. Chrome uses a bundled version of Flash Player, even if there is an NPAPI version of Flash Player installed on the system.)

We are currently working on integrating the same API into Adobe Reader and Acrobat X, and will follow up with another blog post once this functionality is available in version X.

Rendering 3D Content in PDF Files

We also changed the default behavior in Adobe Reader and Acrobat 9.5.1 to disable the rendering of 3D content. Since the majority of consumers do not typically open PDF files that include 3D content and 3D content in untrusted documents has been a previous vector of attack we have disabled this functionality by default starting with version 9.5.1. Users have the option to enable 3D content, but a Yellow Message Bar will flag potentially harmful documents in the event that untrusted documents attempt to render 3D content. IT administrators in managed environments will also have the option of turning this behavior off for trusted documents.

More information on the two changes to content rendering described above is available in the Adobe Reader and Acrobat 9.5.1 release notes.

Further Alignment of the Adobe Reader/Acrobat Update Cycle with Microsoft’s Model

In June 2009, we shipped our first quarterly security update for Adobe Reader and Acrobat. Since then, we have come a long way in putting mitigations into place that make Adobe Reader and Acrobat a less attractive attack target. Sandboxing Adobe Reader and Acrobat X, in particular, has led to greater than expected results. Attackers have indicated through their target selection thus far that the extra effort required to attack version X is not currently worth it. Additionally, we have seen a lower volume of vulnerability reports overall against Adobe Reader and Adobe Acrobat. Given the shift in the threat landscape and the lower volume of vulnerability reports, we have revisited the decision to follow a strict quarterly release cycle.

After three years of shipping a security update once a quarter and announcing the date of the next update the same day we ship the current update, we are making a change. We are shifting to a model that more closely aligns with the familiar “Microsoft Patch Tuesday” cadence. We will continue to publish a prenotification three business days before we release a security update to Adobe Reader and Acrobat. We will continue to publish security updates on the second Tuesday of the month. We will continue to be flexible and respond “out of cycle” to urgent needs such as a zero-day attack. What we are discontinuing is the quarterly cadence and the pre-announcement of the next scheduled release date in the security bulletin for the previous release. We will publish updates to Adobe Reader and Acrobat as needed throughout the year to best address customer requirements and keep all of our users safe.

A Note on the Update Priority Ratings in APSB12-08

Finally, in today’s Security Bulletin, we rated Adobe Reader and Acrobat 9.5.1 for Windows as a “Priority 1″ update, while Adobe Reader and Acrobat X (10.1.2) was rated a “Priority 2″ update. This was an interesting decision, and we thought we would provide some background information: Although there are no exploits in the wild targeting any of the vulnerabilities addressed in Adobe Reader 9.5.1, Adobe Reader 9.x continues to be a target for attackers, so, for users who can not update to Adobe Reader X, we feel that urgently updating Adobe Reader 9.x remains a must to stay ahead of potential attacks.

Since the release of Adobe Reader X, Protected Mode mitigations (or the Protected View mitigations in Adobe Acrobat X version 10.1 and later) continue to be the best way to block potentially malicious behavior in PDF files. Therefore, a “Priority 2″ designation is appropriate for the Adobe Reader X and Acrobat X 10.1.2 updates. Adobe Reader and Acrobat for Macintosh and Linux have not historically been a target of attacks, and therefore are also assigned a “Priority 2.”

How urgently do I need to apply this update? That’s the most common question we get from customers in managed environments when we release a security bulletin. Our current severity ratings do a good job of objectively describing the worst-case scenario involved with a security issue, but they do not necessarily tell a customer all they need to know about the risk and priority of a particular security update. All critical security updates are not created equal. For example, if a Flash Player issue is being exploited in the wild, the update to resolve the vulnerability deserves a much higher priority than, say, a patch for a critical vulnerability in Photoshop. After all, Flash Player is a browser-based plugin with hundreds of millions of customers. Photoshop, on the other hand, has a much smaller customer base and would require significant social engineering to successfully exploit the product. So we started to wonder, how can we communicate the priority of our security updates more effectively?

We want to be as simple and direct as possible about the real-world risk associated with the vulnerabilities addressed in any given security update, and we decided that adopting a separate priority ranking scheme was the best way to accomplish this. Here is the priority scheme we are planning to use to rank security updates in the future:

We’re going to base our priority ranking on historical attack patterns for the relevant product, the type of vulnerability, the platform(s) affected, and any potential mitigations that may be in place. This is a new system, so we may find that adjustments will need to be made. We also believe that continuing to use the current severity ratings makes sense, since this information has been helpful to many customers, so you can expect to see both ratings being used in future security bulletins.

We look forward to your feedback. Our goal is to help our customers in managed environments prioritize updates, so we’ll see if this new priority ranking scheme works to accomplish that! As we have been emphasizing a lot recently, the majority of attacks we are seeing are exploiting software installations that are not up-to-date with the latest security updates, so as always we recommend that users keep their software installations updated with the latest version of Adobe software.