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Why a Zero-Day Attack Doesn’t Mean There’s Nothing You Can Do

BY Rob McLeod

July 8, 2021 | 2 MINS READ

Cybersecurity Strategy


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Originally posted in VMware June 24, 2021

Zero-day attack — these three words can strike fear into CISOs and their organizations.

Simply defined, a zero-day attack is an attack that exploits a software vulnerability that is not known to the vendor or its users. Because the vulnerability is not known to the vendor, there is no patch to repair it. Since the vulnerability is not known to the software’s users, no specific protective actions are taken.

A threat actor equipped with a zero-day exploit is presented with a land of opportunity, which is one reason why these weapons are so highly valued in the cybercrime community and why the attacks can lead to business-disrupting events. Unfortunately, 2021 is on a record-setting pace. Businesses and other organizations need to pay special attention to zero-day threats.

However, as previously defined, a zero-day attack cannot be prevented (e.g., by patching). So what can organizations do?

Recently, VMware Carbon Black and eSentire teamed up to answer this question in an easy-to-understand report and an engaging 30-minute round table both of which draw upon direct observations and the latest cybersecurity research. The shared insights include:

Using the notorious ProxyLogon zero-day episode as an example (see timeline below), the report demonstrates that quickly detecting post-compromise activity (e.g., reconnaissance and domain discovery, persistence through processes, web shells, credential dumping, C2, etc.) is the key to withstanding a zero-day attack.

The round table, featuring threat intelligence experts from both teams, provides additional commentary that touches on:


Detecting and Responding to Zero-Day Attacks: Protecting yourself when patching is not an option

Download the full report

It’s important for IT and security professionals to start the conversation with executives to raise awareness of the business risks associated with zero-day attacks. We must stop assuming there’s nothing that can be done to manage the risk of zero-day attacks. Armed with these insights, organizations can learn how to spot the signs of post-compromise activity; whether a threat actor employs a zero-day exploit or leverages some other vector.

Rob McLeod
Rob McLeod Vice President, Threat Response Unit

As Vice President of eSentire's Threat Response Unit, Rob McLeod is responsible for leading the full lifecycle of Threat Intelligence, Threat Detection, and Threat Research functions at eSentire, including the development of novel machine learning threat detection capabilities. His mission is to bring innovative, differentiated security capabilities to market to protect and defend organizations to manage risk against business-impacting threats.

Rob is a results-focused leader with a passion for data analytics and more than 15 years of experience overseeing diverse business initiatives to bring technical innovation to the highly competitive cybersecurity and telecommunications marketplace.

Rob holds a Bachelor of Applied Computing in Distributed Computing and Communications Systems Technology from the University of Guelph and a Diploma in Wireless and Telecommunications Technology from Humber College.

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