New style of attack can slip past firewalls, prevention systems

Researchers say the ability to deliver this new class of malicious exploits through Port 80 Web traffic ramps up the threat posed by advanced evasion techniques.

Researchers at Stonesoft, the Finnish security company that announced last year the discovery of a new class of evasion techniques for malicious exploits, say they have identified a new set of advanced evasion techniques that can be delivered to a network via port 80 HTTP traffic.

The finding means that AETs can pass undetected by firewalls, which ramps up the threat posed by exploits using the techniques, said Brian Vosburgh, security solutions architect for Stonesoft.

“It’s not necessarily unexpected,” Vosburgh said of the new vector. “It expands the reach of AETs. It becomes a firewall issue, not just an intrusion prevention system issue.”


Related stories:

Emerging cyber threat: Evasion techniques that combine to conquer

Security vendors slow to respond to new evasion techniques


Vosburgh said the company has reported 163 new AETs to the Finnish Computer Emergency Response Team.

Advanced evasion techniques are combinations of simple evasion techniques that can be used to get around standard security tools, such as intrusion detection and prevention systems, that might detect a stand-alone trick. Because they can use multiple combinations of simpler components, there are hundreds of thousands — if not millions — of potential AETs. The value of identifying a few hundred possible technique combinations lies in raising the profile of the threat, Vosburgh said.

“It’s about driving industry to address traffic normalization,” he said.

The company says what is needed to counter this class of threats is better normalization of TCP/IP traffic by network defenses to strip away the evasive tricks and expose the exploits. Progress should be possible through upgrades of current products without requiring wholesale replacement of the security infrastructure.

Evasion techniques have been around for quite a while, and the company began researching the subject in 2009 as part of an effort to see how well its own products identified and responded to them. Stonesoft found that some combinations of techniques were able to slip through undetected and identified 23 AETs last year that tools from other companies also did not detect. It identified another 124 early this year.

The techniques manipulate TCP/IP protocols that underlie the Internet and other IP networks, using tricks such as packet fragmentation and TCP segmentation. Breaking up an exploit and putting it into packet fragments, for instance, can confuse intrusion prevention systems. But the packets will be reassembled by the host device being attacked.

The same types of tricks also can be used with the HTTP and HTTPS protocols, Stonesoft says.

Industry response to the new class of threats has been muted somewhat because, a year after the initial announcement, there still are no verified cases of threats in the wild using AETs. CERT-FI, Finland’s Computer Emergency Response Team, has coordinated the release of vulnerabilities found by Stonesoft to IPS vendors, some of which have begun efforts to block and report the attacks.

Vosburgh said the industry is beginning to pay attention to the issue.

“I don’t want to give the impression that the industry has made great strides in protecting against AETs,” he said. “It hasn’t, and there is still a lot of work that needs to be done around inspection, detection and traffic normalization. However, in the past year, we’ve crossed a major hurdle, which has been getting the network security community to understand just how serious and dangerous AETs are.”

Testing labs and research facilities are beginning to incorporate AETs into testing methodologies and criteria, Vosburgh said, and vendors have started thinking about protection against them.

“In sum, the vendor community is at a point of ‘Hey, we get it. We’re taking it seriously’,” he said.

 

X
This website uses cookies to enhance user experience and to analyze performance and traffic on our website. We also share information about your use of our site with our social media, advertising and analytics partners. Learn More / Do Not Sell My Personal Information
Accept Cookies
X
Cookie Preferences Cookie List

Do Not Sell My Personal Information

When you visit our website, we store cookies on your browser to collect information. The information collected might relate to you, your preferences or your device, and is mostly used to make the site work as you expect it to and to provide a more personalized web experience. However, you can choose not to allow certain types of cookies, which may impact your experience of the site and the services we are able to offer. Click on the different category headings to find out more and change our default settings according to your preference. You cannot opt-out of our First Party Strictly Necessary Cookies as they are deployed in order to ensure the proper functioning of our website (such as prompting the cookie banner and remembering your settings, to log into your account, to redirect you when you log out, etc.). For more information about the First and Third Party Cookies used please follow this link.

Allow All Cookies

Manage Consent Preferences

Strictly Necessary Cookies - Always Active

We do not allow you to opt-out of our certain cookies, as they are necessary to ensure the proper functioning of our website (such as prompting our cookie banner and remembering your privacy choices) and/or to monitor site performance. These cookies are not used in a way that constitutes a “sale” of your data under the CCPA. You can set your browser to block or alert you about these cookies, but some parts of the site will not work as intended if you do so. You can usually find these settings in the Options or Preferences menu of your browser. Visit www.allaboutcookies.org to learn more.

Sale of Personal Data, Targeting & Social Media Cookies

Under the California Consumer Privacy Act, you have the right to opt-out of the sale of your personal information to third parties. These cookies collect information for analytics and to personalize your experience with targeted ads. You may exercise your right to opt out of the sale of personal information by using this toggle switch. If you opt out we will not be able to offer you personalised ads and will not hand over your personal information to any third parties. Additionally, you may contact our legal department for further clarification about your rights as a California consumer by using this Exercise My Rights link

If you have enabled privacy controls on your browser (such as a plugin), we have to take that as a valid request to opt-out. Therefore we would not be able to track your activity through the web. This may affect our ability to personalize ads according to your preferences.

Targeting cookies may be set through our site by our advertising partners. They may be used by those companies to build a profile of your interests and show you relevant adverts on other sites. They do not store directly personal information, but are based on uniquely identifying your browser and internet device. If you do not allow these cookies, you will experience less targeted advertising.

Social media cookies are set by a range of social media services that we have added to the site to enable you to share our content with your friends and networks. They are capable of tracking your browser across other sites and building up a profile of your interests. This may impact the content and messages you see on other websites you visit. If you do not allow these cookies you may not be able to use or see these sharing tools.

If you want to opt out of all of our lead reports and lists, please submit a privacy request at our Do Not Sell page.

Save Settings
Cookie Preferences Cookie List

Cookie List

A cookie is a small piece of data (text file) that a website – when visited by a user – asks your browser to store on your device in order to remember information about you, such as your language preference or login information. Those cookies are set by us and called first-party cookies. We also use third-party cookies – which are cookies from a domain different than the domain of the website you are visiting – for our advertising and marketing efforts. More specifically, we use cookies and other tracking technologies for the following purposes:

Strictly Necessary Cookies

We do not allow you to opt-out of our certain cookies, as they are necessary to ensure the proper functioning of our website (such as prompting our cookie banner and remembering your privacy choices) and/or to monitor site performance. These cookies are not used in a way that constitutes a “sale” of your data under the CCPA. You can set your browser to block or alert you about these cookies, but some parts of the site will not work as intended if you do so. You can usually find these settings in the Options or Preferences menu of your browser. Visit www.allaboutcookies.org to learn more.

Functional Cookies

We do not allow you to opt-out of our certain cookies, as they are necessary to ensure the proper functioning of our website (such as prompting our cookie banner and remembering your privacy choices) and/or to monitor site performance. These cookies are not used in a way that constitutes a “sale” of your data under the CCPA. You can set your browser to block or alert you about these cookies, but some parts of the site will not work as intended if you do so. You can usually find these settings in the Options or Preferences menu of your browser. Visit www.allaboutcookies.org to learn more.

Performance Cookies

We do not allow you to opt-out of our certain cookies, as they are necessary to ensure the proper functioning of our website (such as prompting our cookie banner and remembering your privacy choices) and/or to monitor site performance. These cookies are not used in a way that constitutes a “sale” of your data under the CCPA. You can set your browser to block or alert you about these cookies, but some parts of the site will not work as intended if you do so. You can usually find these settings in the Options or Preferences menu of your browser. Visit www.allaboutcookies.org to learn more.

Sale of Personal Data

We also use cookies to personalize your experience on our websites, including by determining the most relevant content and advertisements to show you, and to monitor site traffic and performance, so that we may improve our websites and your experience. You may opt out of our use of such cookies (and the associated “sale” of your Personal Information) by using this toggle switch. You will still see some advertising, regardless of your selection. Because we do not track you across different devices, browsers and GEMG properties, your selection will take effect only on this browser, this device and this website.

Social Media Cookies

We also use cookies to personalize your experience on our websites, including by determining the most relevant content and advertisements to show you, and to monitor site traffic and performance, so that we may improve our websites and your experience. You may opt out of our use of such cookies (and the associated “sale” of your Personal Information) by using this toggle switch. You will still see some advertising, regardless of your selection. Because we do not track you across different devices, browsers and GEMG properties, your selection will take effect only on this browser, this device and this website.

Targeting Cookies

We also use cookies to personalize your experience on our websites, including by determining the most relevant content and advertisements to show you, and to monitor site traffic and performance, so that we may improve our websites and your experience. You may opt out of our use of such cookies (and the associated “sale” of your Personal Information) by using this toggle switch. You will still see some advertising, regardless of your selection. Because we do not track you across different devices, browsers and GEMG properties, your selection will take effect only on this browser, this device and this website.