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Category Archives for "Security"

“Skyfall attack” was attention seeking

After the Meltdown/Spectre attacks, somebody created a website promising related "Skyfall/Solace" attacks. They revealed today that it was a "hoax".

It was a bad hoax. It wasn't a clever troll, parody, or commentary. It was childish behavior seeking attention.

For all you hate naming of security vulnerabilities, Meltdown/Spectre was important enough to deserve a name. Sure, from an infosec perspective, it was minor, we just patch and move on. But from an operating-system and CPU design perspective, these things where huge.

Page table isolation to fix Meltdown is a fundamental redesign of the operating system. What you learned in college about how Solaris, Windows, Linux, and BSD were designed is now out-of-date. It's on the same scale of change as address space randomization.

The same is true of Spectre. It changes what capabilities are given to JavaScript (buffers and high resolution timers). It dramatically increases the paranoia we have of running untrusted code from the Internet. We've been cleansing JavaScript of things like buffer-overflows and type confusion errors, now we have to cleanse it of branch prediction issues.

Moreover, not only do we need to change software, we need to change the CPU. No, we won't get rid of branch-prediction Continue reading

Web Cache Deception Attack revisited

In April, we wrote about Web Cache Deception attacks, and how our customers can avoid them using origin configuration.

Read that blog post to learn about how to configure your website, and for those who are not able to do that, how to disable caching for certain URIs to prevent this type of attacks. Since our previous blog post, we have looked for but have not seen any large scale attacks like this in the wild.

Today, we have released a tool to help our customers make sure only assets that should be cached are being cached.

A brief re-introduction to Web Cache Deception attack

Recall that the Web Cache Deception attack happens when an attacker tricks a user into clicking a link in the format of http://www.example.com/newsfeed/foo.jpg, when http://www.example.com/newsfeed is the location of a dynamic script that returns different content for different users. For some website configurations (default in Apache but not in nginx), this would invoke /newsfeed with PATH_INFO set to /foo.jpg. If http://www.example.com/newsfeed/foo.jpg does not return the proper Cache-Control headers to tell a web cache not to cache the content, web caches may decide to cache Continue reading

VMware NSX for vSphere 6.4 Eases Operations, Improves Application Security with Context

Summary: Generally available today, VMware NSX for vSphere 6.4 raises the bar for application security and planning, and introduces context-aware micro-segmentation

For those working in security, thinking and talking about the cyber threats in the world is a constant, a necessary evil. So, for a moment, let’s summon a better time to our memory. Remember when breaches didn’t keep us up at night? The threat of a breach didn’t hang over our heads with an associated cost of millions of dollars and the privacy of our users. In fact, it did, but they weren’t frequent or public enough to cause the awakening that they do today. We put up a wall at the perimeter to keep the bad guys out, and prayed.

OK, back to modern times. Today, we know the story is much different, for better and for worse. Breaches are more prevalent, but our defenses are more sophisticated and more importantly, they’re continuously evolving (just like the breaches). One major piece of this newer defense picture is micro-segmentation. With micro-segmentation, security policies traditionally only enforced at the perimeter are now brought down to the application. Micro-segmentation has gained massive traction and entered the mainstream, with most cloud Continue reading

Introducing Cloudflare Access: Like BeyondCorp, But You Don’t Have To Be A Google Employee To Use It

Introducing Cloudflare Access: Like BeyondCorp, But You Don’t Have To Be A Google Employee To Use It

Tell me if this sounds familiar: any connection from inside the corporate network is trusted and any connection from the outside is not. This is the security strategy used by most enterprises today. The problem is that once the firewall, or gateway, or VPN server creating this perimeter is breached, the attacker gets immediate, easy and trusted access to everything.

Introducing Cloudflare Access: Like BeyondCorp, But You Don’t Have To Be A Google Employee To Use It CC BY-SA 2.0 image by William Warby

There’s a second problem with the traditional security perimeter model. It either requires employees to be on the corporate network (i.e. physically in the office) or using a VPN, which slows down work because every page load makes extra round trips to the VPN server. After all this hassle, users on the VPN are still highly susceptible to phishing, man-in-the-middle and SQL injection attacks.

A few years ago, Google pioneered a solution for their own employees called BeyondCorp. Instead of keeping their internal applications on the intranet, they made them accessible on the internet. There became no concept of in or outside the network. The network wasn’t some fortified citadel, everything was on the internet, and no connections were trusted. Everyone had to prove they are who they say they are.

Continue reading

AT&T’s Rupesh Chokshi on NFV/SDN-enabled Business Networking

Rupesh Chokshi AT&T has been aggressively transforming its core network with software-defined networking (SDN) and network function virtualization (NFV), gaining the ability to offer on-site infrastructure to enterprises in an innovative, simplified, and easy to consume model. The resulting platform, AT&T FlexWareSM, provides best-in-class, virtualized network functions to businesses across the entire spectrum of the market. From... Read more →

The Overoptimization Meltdown

In simple terms Meltdown and Spectre are simple vulnerabilities to understand. Imagine a gang of thieves waiting for a stage coach carrying a month’s worth of payroll.

There are two roads the coach could take, and a fork, or a branch, where the driver decides which one to take. The driver could take either one. What is the solution? Station robbers along both sides of the branch, and wait to see which one the driver chooses. When you know, pull the resources from one branch to the other, so you can effectively rob the stage. This is much the same as a modern processor handling a branch—the user could have put anything into some field, or retreived anything from a database, that might cause the software to run one of two sets of instructions. There is no way for the processor to know, so it runs both of them.

To run both sets of instructions, the processor will pull in the contents of specific memory locations, and begin exexuting code across these memory locations. Some of these memory locations might not be pieces of memory the currently running software is supposed to be able to access, but this is not Continue reading

Can IPv4 Networks Be Compromised via IPv6?

The Fox-IT International Blog recently published an article on how IPv4 networks can be compromised via IPv6. The attack vector relies on the default IPv6 configuration in the Windows operating system to spoof DNS replies by acting as a malicious DNS server to redirect traffic to an attacker-specified endpoint. The Windows Proxy Auto Discovery (WPAD) feature can also be exploited in order to relay credentials and authenticate to various services within the network, using a tool called called mitm6 created by Fox-IT.

Fox-IT is recommending that IPv6 is disabled when it is not being used, as disabling Proxy Auto Detection. This of course means that Windows-based hosts are unable to switch preference to IPv6 when it is available (which all versions since Windows Vista will do), and that IPv6 would need to be explicitly re-enabled on hosts.

The article makes some important points, but IPv4 and IPv6 are fundamentally incompatible on a wire level and it needs to be understood they can’t communicate with each other except through translation devices. There are a number of known issues (including this one) with the security of automatic configuration mechanisms running on Local Area Networks, both under IPv6 and IPv4, but these require physical access to Continue reading