Keep VPNs safe from DDoS and other attacks as remote working continues during lockdown

Bryan Hamman

JOHANNESBURG – April 29, 2020 – If cybercrime were a country, it would have the 13th highest gross domestic product (GDP) in the world, with large multi-national operations earning more than US$1 billion annually.

This is according to the recently-released 2H 2019 NETSCOUT Threat Intelligence Report, which says that this gives cybercriminals plenty of motivation to continue unleashing an onslaught of different types of attacks on the world. This includes phishing, distributed denial of service (DDoS) attacks, ransomware and many other forms of malicious malware.

And that was just last year – where are we at now that we’re four months into 2020?

“This year,” says Bryan Hamman, Regional Director at NETSCOUT, a leading provider of service assurance, security and business analytics, “cybercriminals have been given a golden opportunity to take advantage of the global COVID-19 pandemic to launch attacks on people working from home, as companies try their utmost to keep their organisations operational.

“The fact that so many white-collar workers are now working remotely has, unfortunately, opened up nefarious new routes for cybercriminal elements around the globe. Defending business continuity is of paramount importance, and employees must now rely on VPNs to access critical business applications, which makes VPN endpoints – which are often undefended - a business lifeline.”

A remote access VPN securely connects a device outside the corporate office to the network. Known as endpoints, these can include smartphones, tablets and laptops. Although VPN traffic is encrypted, vulnerabilities at the endpoints do exist.

NETSCOUT Security CTO Darren Anstee clarifies in a NETSCOUT blog, “The availability of the remote access systems that give us a route into our corporate networks is really crucial now. However, in many cases the remote access endpoints that we’re relying on are vulnerable to DDoS attack, and there are a lot of people out there who are looking to exploit this. We are seeing an increase in DDoS attacks targeting the TCP[1] and UDP[2] ports being used by various VPN solutions.”

DDoS attacks are an attempt to exhaust the resources available to a network, application, or service so that genuine users cannot gain access. Such attacks on VPN endpoints would have significant business continuity consequences.

Additionally, says Anstee, attackers are able to mix and match different DDoS vectors to maximise their chances of success, as follows:

  • Volumetric attacks saturate connectivity, filling up the pipes that connect network and resources together.
  • State exhaustion attacks target infrastructure, such as load balancers[3] and firewalls[4], congesting and overwhelming state tables[5].
  • Application layer attacks target applications at layer seven[6] with queries and authentication requests that use up resources and cause systems to come to a halt.

And so, if an attack saturates the link to a VPN endpoint or exhausts its state tables, home workers are effectively cut off from corporate resources. The question then is: how does an organisation protect itself from these insidious threats, to protect both itself as well as its business continuity during these unprecedented times?

Anstee advises that organisations need to apply best practice defences to protect VPN endpoints in the same way that customer-facing services are protected. This could include:

  • Extending current capabilities, making sure that traffic to VPN endpoints is routed through an existing suite of on-premises DDoS solutions;
  • Upgrading licences if required, to handle additional throughput;
  • Adding new defence capabilities to networks, either physically or as virtual network functions; and
  • Ensuring speed of reaction, for example via on-premises DDoS protection solutions.

Anstee says that hybrid DDoS defences, which combine localised protection with cloud-based backup, constitute the current best practice for complete protection.

In conclusion, Hamman adds, “The global pandemic is obviously having a huge impact on businesses around the world as they continue trying to operate. As South Africans phase the reality of having the lockdown lifted in a phased approach, we realise that remote working for many will be here for at least a while longer. We therefore urge companies to ensure that they have put in place the required cybersecurity measures to protect their remote workers as these unprecedented times continue for the foreseeable future.”

NETSCOUT products and solutions are distributed throughout Africa by value-added distributor, Networks Unlimited Africa.

Please contact Janco Taljaard at This email address is being protected from spambots. You need JavaScript enabled to view it. for more information.

[1] TCP (Transmission Control Protocol) is a standard that defines how to establish and maintain a network conversation through which application programs can exchange data. TCP works with the Internet Protocol (IP), which defines how computers send packets of data to each other. Together, TCP and IP are the basic rules defining the Internet.

[2] UDP (User Datagram Protocol) is part of the TCP/IP suite of protocols used for data transferring. UDP is a known as a ‘stateless’ protocol, meaning it doesn't acknowledge that the packets being sent have been received. For this reason, the UDP protocol is typically used for streaming media.

[3] A load balancer is a piece of hardware (or virtual hardware) that acts to distribute network and/or application traffic across different servers. 

[4] A firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules, typically establishing a barrier between a trusted internal network and untrusted external network.

[5] A firewall maintains a ‘state table’ of the internal structure of the firewall – it is where information is stored.

[6] For IT professionals, the seven layers refer to the Open Systems Interconnection (OSI) model, a conceptual framework that describes the functions of a networking or telecommunication system. Applications that work at Layer 7 are the ones that users interact with directly, such as web browsers and other apps such as Skype, Outlook, Office.


About Networks Unlimited Africa

Networks Unlimited Africa is a value-added distributor, offering the best and latest solutions within the converged technology, data centre, networking, and security landscapes. The company distributes best-of-breed products, including Altaro, Attivo Networks, Carbon Black, Cofense, Fortinet, F5, Hitachi Vantara, Mellanox Technologies, NETSCOUT, ProLabs, RSA, Rubrik, SevOne, Silver Peak, Tenable, Tintri and Uplogix.

Our product portfolio provides cutting edge solutions from the network edge to the data centre, and addresses key areas such as cybersecurity in the IT/OT space, hybrid cloud, datacentre and infrastructure, networking and integration, SD-WAN solutions, network performance management and application performance management, application delivery networking and load balancing, DataOps management and data management, and backup and recovery solutions. Most of our solutions are highly regarded by Gartner and will be found on their respective magic quadrants.

Since its formation in 1994, Networks Unlimited Africa has continually adapted to today's progressively competitive and evolving marketplace, and has reaped the benefits by being a leading value-added distributor (VAD) within the Sub-Saharan Africa market.  


Networks Unlimited
Janco Taljaard
+27 (0) 11 202 8400
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Vivienne Fouché
+27 (0) 82 602 1635
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