Attacks/Breaches

2/23/2014
11:20 PM
Connect Directly
Google+
Twitter
RSS
E-Mail
50%
50%

Researchers Bypass Protections In Microsoft's EMET Security Tool

Bromium Labs researchers create exploit that the Enhanced Mitigation Experience Toolkit (EMET) 4.1 can't detect

RSA CONFERENCE 2014 -- San Francisco -- Microsoft's free Enhanced Mitigation Experience Toolkit (EMET) 4.1 aimed at mitigating zero-day exploits can be cheated by attackers to sneak malware past it, researchers have found.

RSA Conference 2014
Click here for more articles about the RSA Conference.

Bromium Labs, led by security researcher Jared DeMott, was able to successfully bypass several key defenses in Microsoft's EMET, mainly taking advantage of the inherent weakness of its reliance on known vectors of return-oriented programming (ROP) exploitation attack methods. "Any tool trying to block or prevent an exploit based on something that's known is always going to have that problem as an architecture," says Rahul Kashyap, chief security architect and head of security research at Bromium.

"There will always be some code you don't know about, like we demonstrate" in our research, says Kashyap, who is also the founder of Bromium. Bromium was able to bypass EMET's stack pivot protection and EAF (Export Address Table Filtering), which the researchers disabled.

Even so, the Bromium team says it would take a determined attacker building customized payloads to cheat EMET as they were able to do in their research. "EMET is a great tool; I would recommend it to people. It takes a lot of effort to be able to bypass everything available in it," Kashyap says. "We were able to craft an exploit to bypass EMET."

And there may even be more weaknesses in the tool, he says, if the researchers had dug "even deeper."

EMET's goal is to raise the bar and cost of exploitation for the attackers: "So the question really is not can EMET be bypassed. Rather, does EMET sufficiently raise the cost of exploitation? The answer to that is likely dependent upon the value of the data being protected. For organizations with data of significant value, we submit that EMET does not sufficiently stop customized exploits," Mott wrote in his paper.

Bromium alerted Microsoft with details of its research and recommended that EMET set virtual memory protection by default, come up with a new EAF protection approach, and expand return-oriented programming mitigations to 64-bit code. Kashyap says he expects Microsoft to address the issues in the next version of EMET.

Jonathan Ness, principal security development manager for Microsoft Trustworthy Computing, said EMET 4.1 has a setting that can prevent such bypasses. "Microsoft collaborated with Bromium on their latest research to ensure continued protection for our customers. The Enhanced Mitigation Experience Toolkit (EMET) 4.1 contains a setting to address this issue and help customers with their ongoing defense-in-depth strategies," he says.

Meanwhile, Mott says that even with the fixes Bromium recommends in its report for EMET, cheating the tool still could occur.

"But even with those fixes, many of the weaknesses are generic in nature and unlikely to be sufficiently addressed by userland protection technologies like EMET. EMET does not protect against kernel vulnerabilities, or help against non-exploit attacks such as Java sandbox escapes. Other similar technologies like Anti-Exploit and Core Force suffer from the same generic problem: mitigations that run on an even playing field with malicious code will/can be bypassed given sufficient attacker interest," Mott wrote in his report, which was published today. "To counter such attacks, we believe that an approach that does not rely on exploitation payload based vectors is needed. As demonstrated, exploit payloads continue to evolve."

[One of the three finalist entries for Microsoft's first-ever BlueHat Prize for building new security defense technologies is now part of the software giant's free Enhanced Mitigation Experience Toolkit (EMET). See Microsoft Adds BlueHat Prize Finalist's Technology To Its Free Toolkit .]

This isn't the first time researchers have been able to sneak malware past EMET: Three other researches previously demonstrated bypasses of earlier versions of the tool. Mott presented his findings here today at the B Sides conference. His paper is available for download via this link.

Have a comment on this story? Please click "Add Your Comment" below. If you'd like to contact Dark Reading's editors directly, send us a message. Kelly Jackson Higgins is Executive Editor at DarkReading.com. She is an award-winning veteran technology and business journalist with more than two decades of experience in reporting and editing for various publications, including Network Computing, Secure Enterprise ... View Full Bio

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
Crowdsourced vs. Traditional Pen Testing
Alex Haynes, Chief Information Security Officer, CDL,  3/19/2019
BEC Scammer Pleads Guilty
Dark Reading Staff 3/20/2019
Register for Dark Reading Newsletters
White Papers
Video
Cartoon Contest
Write a Caption, Win a Starbucks Card! Click Here
Latest Comment: Well, at least it isn't Mobby Dick!
Current Issue
5 Emerging Cyber Threats to Watch for in 2019
Online attackers are constantly developing new, innovative ways to break into the enterprise. This Dark Reading Tech Digest gives an in-depth look at five emerging attack trends and exploits your security team should look out for, along with helpful recommendations on how you can prevent your organization from falling victim.
Flash Poll
The State of Cyber Security Incident Response
The State of Cyber Security Incident Response
Organizations are responding to new threats with new processes for detecting and mitigating them. Here's a look at how the discipline of incident response is evolving.
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2016-10743
PUBLISHED: 2019-03-23
hostapd before 2.6 does not prevent use of the low-quality PRNG that is reached by an os_random() function call.
CVE-2019-9947
PUBLISHED: 2019-03-23
An issue was discovered in urllib2 in Python 2.x through 2.7.16 and urllib in Python 3.x through 3.7.2. CRLF injection is possible if the attacker controls a url parameter, as demonstrated by the first argument to urllib.request.urlopen with \r\n (specifically in the query string or PATH_INFO) follo...
CVE-2019-9948
PUBLISHED: 2019-03-23
urllib in Python 2.x through 2.7.16 supports the local_file: scheme, which makes it easier for remote attackers to bypass protection mechanisms that blacklist file: URIs, as demonstrated by triggering a urllib.urlopen('local_file:///etc/passwd') call.
CVE-2019-9945
PUBLISHED: 2019-03-23
SoftNAS Cloud 4.2.0 and 4.2.1 allows remote command execution. The NGINX default configuration file has a check to verify the status of a user cookie. If not set, a user is redirected to the login page. An arbitrary value can be provided for this cookie to access the web interface without valid user...
CVE-2019-9942
PUBLISHED: 2019-03-23
A sandbox information disclosure exists in Twig before 1.38.0 and 2.x before 2.7.0 because, under some circumstances, it is possible to call the __toString() method on an object even if not allowed by the security policy in place.