Daily Archives: September 18, 2018

CVE-2018-6693 (endpoint_security_for_linux_threat_prevention, endpoint_security_linux_threat_prevention)

An unprivileged user can delete arbitrary files on a Linux system running ENSLTP 10.5.1, 10.5.0, and 10.2.3 Hotfix 1246778 and earlier. By exploiting a time of check to time of use (TOCTOU) race condition during a specific scanning sequence, the unprivileged user is able to perform a privilege escalation to delete arbitrary files.

Drone Assassins, Security Shaming, and Zero-Day – Hack Naked News #189

Drone assassins are cheap, deadly, and at your local store, State Department shamed, MS-ISAC releases advisory advisory PHP vulnerabilities, a nasty piece of CSS code, a Zero-Day bug in CCTV surveillance cameras, and FreeBSD has its own TCP-queue-of-death bug! Jason Wood's expert commentary on The Effectiveness of Publicly Shaming Bad Security!

Full Show Notes: https://wiki.securityweekly.com/HNNEp... Visit http://hacknaked.tv to get all the latest episodes!

Firewalls and the Need for Speed

I was looking for resources on campus network design and found these slides (pdf) from a 2011 Network Startup Resource Center presentation. These two caught my attention:



This bothered me, so I Tweeted about it.

This started some discussion, and prompted me to see what NSRC suggests for architecture these days. You can find the latest, from April 2018, here. Here is the bottom line for their suggested architecture:






What do you think of this architecture?

My Tweet has attracted some attention from the high speed network researcher community, some of whom assume I must be a junior security apprentice who equates "firewall" with "security." Long-time blog readers will laugh at that, like I did. So what was my problem with the original recommendation, and what problems do I have (if any) with the 2018 version?

First, let's be clear that I have always differentiated between visibility and control. A firewall is a poor visibility tool, but it is a control tool. It controls inbound or outbound activity according to its ability to perform in-line traffic inspection. This inline inspection comes at a cost, which is the major concern of those responding to my Tweet.

Notice how the presentation author thinks about firewalls. In the slides above, from the 2018 version, he says "firewalls don't protect users from getting viruses" because "clicked links while browsing" and "email attachments" are "both encrypted and firewalls won't help." Therefore, "since firewalls don't really protect users from viruses, let's focus on protecting critical server assets," because "some campuses can't develop the political backing to remove firewalls for the majority of the campus."

The author is arguing that firewalls are an inbound control mechanism, and they are ill-suited for the most prevalent threat vectors for users, in his opinion: "viruses," delivered via email attachment, or "clicked links."

Mail administrators can protect users from many malicious attachments. Desktop anti-virus can protect users from many malicious downloads delivered via "clicked links." If that is your worldview, of course firewalls are not important.

His argument for firewalls protecting servers is, implicitly, that servers may offer services that should not be exposed to the Internet. Rather than disabling those services, or limiting access via identity or local address restrictions, he says a firewall can provide that inbound control.

These arguments completely miss the point that firewalls are, in my opinion, more effective as an outbound control mechanism. For example, a firewall helps restrict adversary access to his victims when they reach outbound to establish post-exploitation command and control. This relies on the firewall identifying the attempted C2 as being malicious. To the extent intruders encrypt their C2 (and sites fail to inspect it) or use covert mechanisms (e.g., C2 over Twitter), firewalls will be less effective.

The previous argument assumes admins rely on the firewall to identify and block malicious outbound activity. Admins might alternatively identify the activity themselves, and direct the firewall to block outbound activity from designated compromised assets or to designated adversary infrastructure.

As some Twitter responders said, it's possible to do some or all of this without using a stateful firewall. I'm aware of the cool tricks one can play with routing to control traffic. Ken Meyers and I wrote about some of these approaches in 2005 in my book Extrusion Detection. See chapter 5, "Layer 3 Network Access Control."

Implementing these non-firewall-based security choices requries a high degree of diligence, which requires visibility. I did not see this emphasized in the NSRC presentation. For example:


These are fine goals, but I don't equate "manageability" with visibility or security. I don't think "problems and viruses" captures the magnitude of the threat to research networks.

The core of the reaction to my original Tweet is that I don't appreciate the need for speed in research networks. I understand that. However, I can't understand the requirement for "full bandwidth, un-filtered access to the Internet." That is a recipe for disaster.

On the other hand, if you define partner specific networks, and allow essentially site-to-site connectivity with exquisite network security monitoring methods and operations, then I do not have a problem with eliminating firewalls from the architecture. I do have a problem with unrestricted access to adversary infrastructure.

I understand that security doesn't exist to serve itself. Security exists to enable an organizational mission. Security must be a partner in network architecture design. It would be better to emphasize enhance monitoring for the networks discussed above, and think carefully about enabling speed without restrictions. The NSRC resources on the science DMZ merit consideration in this case.

Convergence is the Key to Future-Proofing Security

I published a new article today on the Oracle Security blog that looks at the benefits of convergence in the security space as the IT landscape grows more disparate and distributed.

Security professionals have too many overlapping products under management and it's challenging to get quick and complete answers across hybrid, distributed environments. It's challenging to fully automate detection and response. There is too much confusion about where to get answers, not enough talent to cover the skills requirement, and significant hesitation to put the right solutions in place because there's already been so much investment.

Here's are a couple of excerpts:
Here’s the good news: Security solutions are evolving toward cloud, toward built-in intelligence via Machine Learning, and toward unified, integrated-by-design platforms. This approach eliminates the issues of product overlap because each component is designed to leverage the others. It reduces the burden related to maintaining skills because fewer skills are needed and the system is more autonomous. And, it promotes immediate and automated response as opposed to indecision. While there may not be a single platform to replace all 50 or 100 of your disparate security products today, platforms are emerging that can address core security functions while simplifying ownership and providing open integration points to seamlessly share security intelligence across functions.
 ...
 Forward-looking security platforms will leverage hybrid cloud architecture to address hybrid cloud environments. They’re autonomous systems that operate without relying on human maintenance, patching, and monitoring. They leverage risk intelligence from across the numerous available sources. And then they rationalize that data and use Machine Learning to generate better security intelligence and feed that improved intelligence back to the decision points. And they leverage built-in integration points and orchestration functionality to automate response when appropriate.
Click to read the full article: Convergence is the Key to Future-Proofing Security