Corelight Bright Ideas Blog: NDR & Threat Hunting Blog

PrintNightmare, SMB3 encryption, and your network

By Corelight Labs Team – July 7, 2021

CVE-2021-1675, also tracked in CVE-2021-34527, is a remote code execution vulnerability that targets the Windows Print Spooler service. In a nutshell, there is a Distributed Computing Environment / Remote Procedure Call (DCE/RPC) that allows... Read more »

Introducing the C2 Collection and RDP inferences

By Vince Stoffer – May 17, 2021

We’re excited to announce that the Command and Control (C2) Collection is now available with today’s launch of version 21 of the Corelight software. One of the most important ways that defenders can quickly identify and contain a security incident... Read more »

Small, fast and easy. Pick any three.

By Seth Hall – November 17, 2020

Zeek has been the darling of security defenders looking to get deep visibility into network traffic. Over the last two decades, Zeek has become a household name – widely used by enterprise organizations, educational institutions and government... Read more »

Network Security Monitoring data: Types I, II, and III

By Richard Bejtlich – July 7, 2020

Some critics claim that ever growing encryption renders network security monitoring useless. This opinion is based on a dated understanding of the types and values of data collected and analyzed by computer incident response teams (CIRTs) that... Read more »

Analyzing encrypted RDP connections

By Anthony Kasza – May 12, 2020

Microsoft’s Remote Desktop Protocol (RDP) is used to remotely administer systems within Windows environments. RDP is everywhere Windows is and is useful for conducting remote work. Just like every other remote administration tool, RDP can be used... Read more »

Detecting OpenBSD CVE-2019-19521 SSH exploit attempts

By Anthony Kasza – December 5, 2019

On December 4, Qualys released a security advisory for an authentication bypass vulnerability in OpenBSD, CVE-2019-19521. The vulnerability affects multiple services in OpenBSD including smtpd, sshd, ldapd, and radiusd. This immediately caught our... Read more »

Light in the darkness: New Corelight Encrypted Traffic Collection

By Vince Stoffer – November 19, 2019

This week’s launch of version 18 of our software features the Encrypted Traffic Collection, our first collection of a series of detections and data enrichments created by the Corelight research team. This collection focuses on SSH, SSL/TLS... Read more »

Investigating the effects of TLS 1.3 on Corelight logs, part 2

By Richard Bejtlich – June 2, 2019

Introduction Welcome to part 2 of my three-part series on TLS. In the previous article I briefly introduced TLS, and showed how Corelight would produce logs for a clear-text HTTP session. In this article I will perform the same transaction using TLS... Read more »

How Zeek can provide insights despite encrypted communications

By Anthony Kasza – May 6, 2019

Overview Encrypted communications are ubiquitous. While encryption provides confidentiality, it cannot prevent all means of traffic analysis. Certain protocols, such as SSH and TLS, ensure contents are not directly readable by monitoring systems.... Read more »

Examining aspects of encrypted traffic through Zeek logs

By Richard Bejtlich – February 18, 2019

In my last post I introduced the idea that analysis of encrypted HTTP traffic requires different analytical models. If you wish to preserve the encryption (and not inspect it via a middlebox), you have to abandon direct inspection of HTTP payloads... Read more »