Background on Stuxnet

The story of Stuxnet, the first cyber weapon in history. Focus is on the manipulation of machinery at Natanz, with detailed explanations of machine configuration and operation. A few takeaways for myself after watching: The Stuxnet software impacted the Iranian nuclear program by damaging the project budget. Instead of blowing up the centrifuges, they increased […]

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Enforcing Enterprise Security Controls in Kubernetes using Calico Enterprise

Hybrid cloud infrastructures run critical business resources and are subject to some of the strictest network security controls. Irrespective of the industry and resource types, these controls broadly fall into three categories.

1. Segmenting environments (Dev, Staging, Prod)
2. Enforcing zones (DMZ, Trusted, etc.)
3. Compliance requirements (GDPR, PCI DSS)

Workloads (pods) running on Kubernetes are ephemeral in nature, and IP-based controls are no longer effective. The challenge is to enforce the organizational security controls on the workloads and Kubernetes nodes themselves. Customers need the following capabilities:

• Ability to implement security controls both globally and on a per-app basis: Global controls help enforce segmentation across the cluster, and work well when the workloads are classified into different environments and/or zones using labels. As long as the labels are in place, these controls will work for any new workloads.
• Generate alerts if security controls are tampered with: Anyone with valid permissions can make changes to the controls. There is a possibility that these controls can be modified without proper authorization or even with a malicious intent to bypass the security. Hence, it is important to monitor changes to the policies.
• Produce an audit log showing changes to security controls over time: This is Continue reading

How to Simplify and Accelerate Network Segmentation 

Network segmentation—splitting a network into subnetworks or segments—is widely accepted to be a powerful and effective method for improving cybersecurity within the data center. Yet even though it’s acknowledged to be an essential component of network security hygiene, organizations have frequently avoided putting segmentation into practice.  

Why? Because historically network segmentation has been complex, disruptive, and time-consuming to implement, requiring extensive changes to the physical network and/or network addresses. The potential impact of taking applications offline for network changes means that many organizations decide to forego this industry-wide best practice. Teams that do forge ahead often face months- or years-long effort to create security zones by re–architecting the network, relocating equipment, and re-assigning IP addresses.  

It doesn’t have to be that way. Today there’s an elegant solution that greatly simplifies and accelerates network segmentation: VMware NSX Service-defined Firewall. Purpose–built to protect east-west traffic, VMware Service-defined Firewall enables segmentation without any disruptive physical network or address changes. 

Attackers Love Flat Networks  

To back up a step, let’s examine why network segmentation  Continue reading

Eliminate East-West Traffic Hair-Pinning

A firewall is a firewall, right? While on the surface that assumption may appear to be correct, a closer look reveals that there are critical differences between a traditional, appliance-based firewall that protects your network perimeter and a distributed, scale-out internal firewall that protects east-west traffic within your data center.  

It’s true that both types of firewalls monitor network traffic, detect threats, and block malicious activity. However, appliance-based firewalls are designed to monitor north-south traffic, which has different volumes and characteristics than east-west traffic. Traditional north-south firewalls were never designed to be used interchangeably to protect both north-south and east-west traffic.  

Figure 1: Data center traffic patterns

While it might appear to be the right choice, provisioning appliance-based firewalls for east-west traffic monitoring is not only expensive, it’s highly ineffective in delivering the level of control and performance required to protect growing numbers of dynamic workloads.  

Creating Traffic Jams During Volume Spikes     

One of the most common drawbacks of using appliance-based firewalls as internal firewalls is the need to hairpin east-west traffic to and Continue reading

Protecting Remote Desktops at Scale with Cloudflare Access

Early last year, before any of us knew that so many people would be working remotely in 2020, we announced that Cloudflare Access, Cloudflare’s Zero Trust authentication solution, would begin protecting the Remote Desktop Protocol (RDP). To protect RDP, customers would deploy Argo Tunnel to create an encrypted connection between their RDP server and our edge - effectively locking down RDP resources from the public Internet. Once locked down with Tunnel, customers could use Cloudflare Access to create identity-driven rules enforcing who could login to their resources.

Setting Tunnel up initially required installing the Cloudflare daemon, cloudflared, on each RDP server. However, as the adoption of remote work increased we learned that installing and provisioning a new daemon on every server in a network was a tall order for customers managing large fleets of servers.

What should have been a simple, elegant VPN replacement became a deployment headache. As organizations helped tens of thousands of users switch to remote work, no one had the bandwidth to deploy tens of thousands of daemons.

Message received: today we are announcing Argo Tunnel RDP Bastion mode, a simpler way to protect RDP connections at scale. ? By functioning as a Continue reading

Network-layer DDoS attack trends for Q2 2020

In the first quarter of 2020, within a matter of weeks, our way of life shifted. We’ve become reliant on online services more than ever. Employees that can are working from home, students of all ages and grades are taking classes online, and we’ve redefined what it means to stay connected. The more the public is dependent on staying connected, the larger the potential reward for attackers to cause chaos and disrupt our way of life. It is therefore no surprise that in Q1 2020 (January 1, 2020 to March 31, 2020) we reported an increase in the number of attacks—especially after various government authority mandates to stay indoors—shelter-in-place went into effect in the second half of March.

In Q2 2020 (April 1, 2020 to June 30, 2020), this trend of increasing DDoS attacks continued and even accelerated:

• The number of L3/4 DDoS attacks observed over our network doubled compared to that in the first three months of the year.
• The scale of the largest L3/4 DDoS attacks increased significantly. In fact, we observed some of the largest attacks ever recorded over our network.
• We observed more attack vectors being deployed and attacks were more geographically distributed.

The number Continue reading

The NSX-T Gateway Firewall Secures Physical Servers

To date, our blog series on securing physical servers with NSX Data Center has covered the use of bare metal agents installed in a physical server. In this scenario, NSX bare metal agents provide management and enforcement of security policy for the physical server. For a quick recap of how NSX Data Center secures physical server traffic, please review our first and second blogs in this multi-part series. In this article, we will discuss the use of one of the NSX-T Gateway services of an NSX Edge Node. Specifically, the NSX-T Gateway Firewall secures physical servers.

What’s The NSX-T Edge?

The NSX-T Edge is a feature-rich L3-L7 gateway.  A brief review of some NSX-T Edge services:

• Via Tier-0 Gateway, routing between the logical and the physical using dynamic routing protocols (eBGP and iBGP) as well as static routing
• Via Tier-1 Gateway, routing between logical network segments, or from logical network segments to uplink to the Tier-0 Gateway
• Routing for IPv4 and IPv6 addresses
• Load Balancing via NSX-T Edge, which offers high-availability service for applications and distribution of network traffic load
• Network Address Translation (NAT), available on tier-0 and tier-1 gateways
• To manage IP addresses, the configuration of DNS (Domain Continue reading

Mirai Botnet Exploit Weaponized to Attack IoT Devices via F5 Appliances

Smart use of available resources.

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Worth Reading: How CEOs think

Robert Graham wrote a great article explaining why CEOs don’t care much about cybersecurity or any other non-core infrastructure (including networking, unless you happen to be working for a service provider). It’s a must-read if you want to understand the **** you have to deal with in enterprise environments.

OMG, Not Again: New Mobile Internet Protocol Vulnerabilities

Every now and then a security researcher “discovers” a tunneling protocol designed to be used over a protected transport core and “declares it vulnerable” assuming the attacker can connect to that transport network… even though the protocol was purposefully designed that way, and everyone with a bit of clue knew the whole story years ago (and/or it’s even documented in the RFC).

It was MPLS decades ago, then VXLAN a few years ago, and now someone “found” a “high-impact vulnerability” in GPRS Tunnel Protocol. Recommended countermeasures: whitelist-based IP filtering. Yeah, it’s amazing what a wonderful new tool they found.

Unfortunately (for the rest of us), common sense never generated headlines on Hacker News (or anywhere else).

Announcing the Tigera – Nutanix Partnership

Today we are pleased to announce our partnership with Nutanix, creators of the industry’s most popular hyper-converged infrastructure (HCI) technology. HCI combines datacenter hardware using locally-attached storage resources with intelligent software to create flexible building blocks that replace legacy infrastructure consisting of separate servers, storage networks, and storage arrays.

Networking and securing microservices running Kubernetes and securely accessing external resources can be challenging, often requiring the use of overlay networks and NATs. At scale, this becomes extremely complex. Cloud-native enterprises seeking a consistent container networking experience across multiple cloud environments have adopted Calico, the de facto standard in open-source Kubernetes networking technologies.

Nutanix is now offering Calico as a component of Karbon, Nutanix’s enterprise Kubernetes management solution that enables turnkey provisioning, operations, and lifecycle management of Kubernetes. With this integration, Karbon users can now take advantage of simplified Kubernetes networking and production-grade network security based on Calico’s native tooling, providing scalable throughput that meets the performance demands of Karbon users.

“Karbon, now with Calico embedded, gives our customers significantly more powerful networking and network security capabilities while preserving the simplicity of provisioning and operating a Kubernetes cluster,” said Greg Muscarella, VP of Products at Nutanix. “Calico eliminates Continue reading

Phased Approach to Securing a Data Center

In the fight against relentless cyberattacks, organizations have long relied on traditional perimeter firewalls to protect sensitive workloads and information in the data center. But today, in the era of distributed applications and hybrid cloud environments, we know that perimeter defenses are not enough to stop cybercriminals.  

To improve security postures inside corporate networks — which means protecting against both bad actors who penetrate perimeter defenses and malicious insiders — organizations must monitor, detect, and block hostile east-west (internal) traffic using internal firewalls.  

To date, network and security professionals have generally viewed securing east-west traffic as too complex, expensive, and time-consuming for their brownfield, and even greenfield, data centers. At VMware, we agree with that perception: it’s certainly true for organizations trying to detect and prevent the lateral movement of attackers by employing traditional, appliance-based perimeter firewalls as internal firewalls.  

There’s a Better Way to Secure the Data Center 

Instead of awkwardly forcing appliance-based firewalls to serve as internal firewalls, organizations should employ a distributed, scale-out internal firewall specifically Continue reading

How CEOs think

flowtrackd: DDoS Protection with Unidirectional TCP Flow Tracking

Magic Transit is Cloudflare’s L3 DDoS Scrubbing service for protecting network infrastructure. As part of our ongoing investment in Magic Transit and our DDoS protection capabilities, we’re excited to talk about a new piece of software helping to protect Magic Transit customers: flowtrackd. flowrackd is a software-defined DDoS protection system that significantly improves our ability to automatically detect and mitigate even the most complex TCP-based DDoS attacks. If you are a Magic Transit customer, this feature will be enabled by default at no additional cost on July 29, 2020.

TCP-Based DDoS Attacks

In the first quarter of 2020, one out of every two L3/4 DDoS attacks Cloudflare mitigated was an ACK Flood, and over 66% of all L3/4 attacks were TCP based. Most types of DDoS attacks can be mitigated by finding unique characteristics that are present in all attack packets and using that to distinguish ‘good’ packets from the ‘bad’ ones. This is called "stateless" mitigation, because any packet that has these unique characteristics can simply be dropped without remembering any information (or "state") about the other packets that came before it. However, when attack packets have no unique characteristics, then "stateful" mitigation is required, because whether a Continue reading

In defense of open debate

Zero Trust and the Cookie Metaphor

In old presentations on network security (watch this space; I’m working on a new security course for Ignition in the next six months or so), I would use a pair of chocolate chip cookies as an illustration for network security. In the old days, I’d opine, network security was like a cookie that was baked to be crunchy on the outside and gooey on the inside. Now-a-days, however, I’d say network security needs to be more like a store-bought cookie—crunchy all the way through. I always used this illustration to make a point about defense-in-depth. You cannot assume the thin crunchy security layer at the edge of your network—generally in the form of stateful packet filters and the like (okay, firewalls, but let’s leave the appliance world behind for a moment)—is what you really need.

There are such things as insider attacks, after all. Further, once someone breaks through the thin crunchy layer at the edge, you really don’t want them being able to move laterally through your network.

The United States National Institute of Standards and Technology (NIST) has released a draft paper describing Zero Trust Architecture, which addresses many of the same concerns as the cookie that’s crunchy Continue reading

From Micro-segmentation to Internal Firewalling

The Evolution of VMware NSX Service-defined Firewall

Today, many people take micro-segmentation for granted. It’s incredible to recall that just a few years ago, VMware introduced micro-segmentation to support the concept of Zero Trust — a security model that does not automatically trust entities within the security perimeter. Fast forward to the present, and many people have embraced that concept and made it their own. Meanwhile, VMware has extended its solution for micro-segmentation into a full-blown internal firewall. Let’s step back in time and see how VMware progressed from the initial micro-segmentation use case to today’s powerful Service-defined Firewall, deployed by thousands of organizations.

Pioneering the Market for Micro-segmentation

Back in 2013, VMware pioneered micro-segmentation with the release of VMware NSX, the VMware network virtualization and security platform, which propelled VMware into the world of software-defined network and security virtualization. This initial release enabled customers to run a complete Layer 2-Layer 4 stack in software. The guiding philosophy was to make world-class security easy to operationalize.

Some customers used NSX for network segmentation: they created virtual security zones in software where they had previously used hardware. Other customers adopted NSX for micro-segmentation: they were now able to provide Continue reading

No Humans Involved: Mitigating a 754 Million PPS DDoS Attack Automatically

On June 21, Cloudflare automatically mitigated a highly volumetric DDoS attack that peaked at 754 million packets per second. The attack was part of an organized four day campaign starting on June 18 and ending on June 21: attack traffic was sent from over 316,000 IP addresses towards a single Cloudflare IP address that was mostly used for websites on our Free plan. No downtime or service degradation was reported during the attack, and no charges accrued to customers due to our unmetered mitigation guarantee.

The attack was detected and handled automatically by Gatebot, our global DDoS detection and mitigation system without any manual intervention by our teams. Notably, because our automated systems were able to mitigate the attack without issue, no alerts or pages were sent to our on-call teams and no humans were involved at all.

During those four days, the attack utilized a combination of three attack vectors over the TCP protocol: SYN floods, ACK floods and SYN-ACK floods. The attack campaign sustained for multiple hours at rates exceeding 400-600 million packets per second Continue reading

The Hedge Pdocast Episode 43: Ivan Pepelnjak and Trusting Routing Protocols

Can you really trust what a routing protocol tells you about how to reach a given destination? Ivan Pepelnjak joins Nick Russo and Russ White to provide a longer version of the tempting one-word answer: no! Join us as we discuss a wide range of issues including third-party next-hops, BGP communities, and the RPKI.

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Sandboxing in Linux with zero lines of code

Modern Linux operating systems provide many tools to run code more securely. There are namespaces (the basic building blocks for containers), Linux Security Modules, Integrity Measurement Architecture etc.

In this post we will review Linux seccomp and learn how to sandbox any (even a proprietary) application without writing a single line of code.

Tux by Iwan Gabovitch, GPL
Sandbox, Simplified Pixabay License

Linux system calls

System calls (syscalls) is a well-defined interface between userspace applications and the operating system (OS) kernel. On modern operating systems most applications provide only application-specific logic as code. Applications do not, and most of the time cannot, directly access low-level hardware or networking, when they need to store data or send something over the wire. Instead they use system calls to ask the OS kernel to do specific hardware and networking tasks on their behalf:

Apart from providing a generic high level way for applications to interact with the low level hardware, the system call architecture allows the OS kernel to manage available resources between applications as well as enforce policies, like application permissions, networking access control lists etc.

Linux seccomp

Linux seccomp is yet another syscall on Linux, but it is a bit Continue reading