Today, we are thrilled to announce a preview release of the next version of the Enhanced Mitigation Experience Toolkit, better known as EMET. You can download EMET 5.0 Technical Preview here. This Technical Preview introduces new features and enhancements that we expect to be key components of the final EMET 5.0 release. We are releasing this technical preview to gather customer feedback about the new features and enhancements. Your feedback will affect the final EMET 5.0 technical implementation. We encourage you to download this Technical Preview, try it out in a test environment, and let us know how you would like these features and enhancements to show up in the final version. If you are in San Francisco, California, for the RSA Conference USA 2014, please join us at the Microsoft booth (number 3005) for a demo of EMET 5.0 Technical Preview and give us feedback directly in person. Several members of the EMET team will be demonstrating at the Microsoft booth for the entire Conference.
As mentioned, this Technical Preview release implements new features to disrupt and block the attacks that we have detected and analyzed over the past several months. The techniques used in these attacks have inspired us with new mitigation ideas to disrupt exploitation and raise the cost to write reliable exploits. The EMET 5.0 Technical Preview also implements additional defensive mechanisms to reduce exposure from attacks.
The two new features introduced in EMET 5.0 Technical Preview are the Attack Surface Reduction (ASR) and the Export Address Table Filtering Plus (EAF+). Similar to what we have done with EMET 3.5 Technical Preview, where we introduced a new set of mitigations to counter Return Oriented Programming (ROP), we are introducing these two new mitigations and ask for your feedback on how they can be improved. Of course, they are a “work in progress.” Our goal is to have them polished for the final version of EMET 5.0.
Let’s see in detail what these two new mitigations do, and the reasoning that led us to their implementation.
Attack Surface Reduction
In mid-2013, we published a Fix it solution to disable the Oracle Java plug-in in Internet Explorer. We received a lot of positive feedback and a number of suggestions on how we could improve the Fix it. The most recurring suggestion we received was to allow the Oracle Java plug-in on intranet websites, which commonly run Line-of-Business applications written in Java, while blocking it on Internet Zone websites. In addition to that Java-related customer feedback, we have also seen a number of exploits targeting the Adobe Flash Player plug-in. For example, the RSA breach was enabled by an Adobe Flash Player exploit embedded inside a Microsoft Excel file and a number of targeted attacks have been carried out by Adobe Flash Player exploits embedded in Microsoft Word documents, as described by Citizen Lab. We decided to design a new feature that can be used to mitigate similar situations and to help to reduce the attack surface of applications. We call this feature Attack Surface Reduction (ASR), and it can be used as a mechanism to block the usage of a specific modules or plug-ins within an application. For example, you can configure EMET to prevent Microsoft Word from loading the Adobe Flash Player plug-in, or, with the support of security zones, you can use EMET to prevent Internet Explorer from loading the Java plug-in on an Internet Zone website while continuing to allow Java on Intranet Zone websites.
The example below shows ASR in action, preventing Microsoft Word from launching an Adobe Flash Player file embedded in the document. By default, EMET 5.0 Technical Preview comes pre-configured to block certain plug-ins from being loaded by Internet Explorer, Microsoft Word and Microsoft Excel. The feature is fully configurable by changing two registry keys that list the names of the plug-ins to block, and, if supported, the security zones that allow exceptions. For more details on how to configure ASR please refer to the EMET 5.0 Technical Preview user guide.
We also added new capabilities to the existing Export Address Table Filtering (EAF). EAF+ consolidates protection of lower-level modules and prevents certain exploitation techniques used to build dynamic ROP gadgets in memory from export tables. EAF+ can be enabled through the “Mitigation Settings” ribbon. When EAF+ is enabled, it will add the following additional safeguards over-and-above the existing EAF checks:
Add protection for KERNELBASE exports in addition to the existing NTDLL.DLL and KERNEL32.DLL
Perform additional integrity checks on stack registers and stack limits when export tables are read from certain lower-level modules
Prevent memory read operations on protected export tables when they originate from suspicious modules that may reveal memory corruption bugs used as “read primitives” for memory probing
For example, the third protection mechanism in the list above mitigates the exploitation technique developed in Adobe Flash Player used in some recent Internet Explorer exploits (CVE-2013-3163 and CVE-2014-0322), where the attacker attempted to build ROP gadgets by scanning the memory and parsing DLL exports using ActionScript code. Exploits for these vulnerabilities are already blocked by other EMET mitigations. EAF+ provides another way to disrupt and defeat advanced attacks. The screenshot below shows the exploit for CVE-2014-0322 in action on Internet Explorer protected by EMET 5.0 Technical Preview with only EAF+ enabled.
This Technical Preview enables the “Deep Hooks” mitigation setting. We have been working with third-party software vendors whose products do not run properly with Deep Hooks enabled. We believe these vendors have resolved the application compatibility issues that previously existed with Deep Hooks enabled. We enable Deep Hooks in the Technical Preview to evaluate the possibility of having this setting turned on by default in the final EMET 5.0 release because it has proven to be effective against certain advanced exploits using ROP gadgets with lower level APIs. We have also introduced some additional hardening to protect EMET’s configuration when loaded in memory, and fixed several application compatibility issues including a common one that involves Adobe Reader and the “MemProt” mitigation.
We’d like to thank Spencer J. McIntyre from SecureState, Jared DeMott from Bromium Labs, along with Peleus Uhley and Ashutosh Mehra from the Adobe Security team for their collaboration on the EMET 5.0 Technical Preview.
We are excited for this Technical Preview and we hope that the additions are as valuable for our customers as they are for us. We invite you to install and give EMET 5.0 Technical Preview a try; we look forward to hearing your feedback and suggestions on how to enhance the new features that we have introduced. We would also welcome any suggestions for additional new features you’d like to see included in the final version of EMET 5.0. We greatly value the feedback we receive, and we want to build a product that not only provides additional protection to systems but is also easy to use and configure. We then invite you all to download EMET 5.0 Technical Preview and drop us a line!
The EMET Team