Security | Threat Detection | Cyberattacks | DevSecOps | Compliance

Episode 7 - Practical AI for Zeek, MITRE, and Security Docs

In Episode 7 of Corelight DefeNDRs, join me, Richard Bejtlich, as I sit down with Dr. Keith Jones, Corelight's principal security researcher, to discuss the practical applications of AI in enhancing network security. We delve into how large language models (LLMs) can assist in cleaning up documentation and generating Zeek scripts, sharing insights from our extensive experience in incident response and coding. Keith reveals the challenges and successes he has encountered using LLMs to streamline processes, including their role in analyzing MITRE techniques.

Episode 6 - Detecting DNS Covert Channels in the Wild (Part 2)

In Episode 6 of Corelight DefeNDRs, we delve deeper into the fascinating world of DNS covert channels with Vern Paxson, our chief scientist and co-founder. Continuing from our previous discussion, Vern shares his insights on techniques developed to detect these stealthy channels utilized by intruders to evade security measures. We explore the innovative approach of leveraging time series analysis of DNS lookups, how to distinguish benign traffic from potential threats, and the real-world implications of our findings across significant datasets.

Episode 5 - Detecting DNS Covert Channels in the Wild (Part 1)

In Episode 5 of Corelight Defenders, I, Richard Bejtlich, engage with Corelight's co-founder and chief scientist, Vern Paxson, to delve into the intricate world of DNS covert channels. We explore how adversaries exploit DNS lookups to silently communicate within tightly controlled enterprise environments. Vern explains various methods attackers may use, from encoding data in seemingly benign domain names to manipulating the timing of requests. Our discussion highlights the challenges of detecting these covert channels, especially in the presence of network monitoring.

Inside the mind of a cybersecurity threat hunter part 3: hunting for adversaries moving inside your network

Welcome back to our threat hunting series with Corelight and CrowdStrike. In our previous posts, we armed you with techniques to spot adversaries during Initial Access and how they establish Persistence to maintain their foothold. Now, we're diving into the shadowy dance of Defense Evasion and Lateral Movement.

Detecting CVE-2025-20393 exploitation: catching UAT-9686 on Cisco appliances

CVE-2025-20393 is a CVSS 10.0 Remote Code Execution (RCE) flaw in Cisco Secure Email Gateways currently being actively exploited by China-nexus groups. A recent advisory from Cisco Talos details how an actor dubbed “UAT-9686” is leveraging this vulnerability to target Cisco Secure Email Gateways (ESA) and Secure Email and Web Managers (SMA). The attack allows threat actors to execute arbitrary commands with root privileges and deploy persistence mechanisms.

Episode 4 - Staying Curious: Lessons from 25 Years in Cybersecurity

In Episode 4 of Corelight Defenders, I sit down with Angela Loomis, Corelight's Director of Technical Account Management, to explore her remarkable 25-year journey in cybersecurity. Angela shares her unconventional entry into the field, starting from a background in television production to becoming a leader in security strategy. We delve into the importance of curiosity in cybersecurity, discussing how diverse experiences enrich the profession, and whether formal education might dampen that curiosity.

How to detect React2Shell attacks using network-based threat hunting

How do you find React2Shell vulnerabilities or detect React2Shell attacks in real environments? In this video, Corelight cloud security researcher David Burkett walks through how to threat hunt React2Shell by focusing on post-exploitation behavior at the network level. Instead of relying on exploit signatures, the approach uses application baselining and network traffic analysis to identify abnormal behavior.

How to React(.js) to React2Shell and detecting behaviors to catch the Next(.js) big RCE

Critical vulnerabilities in React Server Components (CVE-2025-55182) and Next.js (CVE-2025-66478) enable unauthenticated remote code execution in default configurations. The flaw resides in the "Flight" protocol used for server-side rendering, making it a sought after target for adversaries looking to bypass standard controls. While the public discourse is currently cluttered with unreliable exploits, we need to ground our defense in verifiable network evidence.

Episode 3 - Network Visibility in the Cloud: Why Network Traffic Analysis Remains Critical

Richard Bejtlich discusses cloud security from a network-centric perspective with Corelight's cloud security researcher, David Burkett. They explore why monitoring network traffic remains essential in cloud environments, despite the presence of native security features offered by cloud providers. David highlights common threats such as container compromises, coin miners, and supply chain attacks, emphasizing the value of traffic visibility for detecting unusual behaviors and breaches.

Episode 2 - Inside the Black Hat NOC: Defending a hostile conference network

Richard Bejtlich talks with Corelight Principal Technical Marketing Engineer Mark Overholser about what it takes to run the Black Hat Network Operations Center and keep a “hostile” training network safe. They walk through how partners like Corelight, Cisco, Palo Alto Networks, Arista, and Lumen build and monitor the conference network, how the team tells lab traffic from real infections, and why misconfigured self hosted services still show up in surprising ways.