Detecting Log4j exploits via Zeek when Java downloads Java

Detecting Log4j exploits via Zeek when Java downloads Java

We have published an initial blog on the Log4j exploit and a followup blog with a second detection method for detecting the first stage of exploits occurring over LDAP.  Today, we will discuss a third detection method, this one focused on the... Read more »

Detecting Log4j via Zeek & LDAP traffic

We recently discussed some methods for detecting the Log4j exploit, and we’ve now developed another method that everyone running Zeek® or a Corelight sensor can use. Our new approach is based on the rarity of legitimate downloads of Java via LDAP.... Read more »

Simplifying detection of Log4Shell

Simplifying detection of Log4Shell

Security workers across the world have been busy since last Friday dealing with CVE-2021-44228, the log4j 0-day known as Log4Shell, that is already being heavily exploited across the Internet. Given the huge number of systems that embed the... Read more »

Getting the most out of your NIDS

Network Intrusion Detection Systems (NIDS) are widely deployed by the most sophisticated blue teams in the world. For well-funded organizations, there is little question about the value of NIDS, but adoption is not uniform across the entire... Read more »

Zeek in its sweet spot: Detecting F5’s Big-IP CVE10 (CVE-2020-5902)

Having a CVE 10 unauthenticated Remote Code Execution vulnerability on a central load balancing device? That’s bad… Read more »

DNS over TLS and DNS over HTTPS

In this post, we’ll explore DNS over TLS (DoT) and DNS over HTTPS (DoH).  Read more »

Using Corelight to monitor and identify exploited VPNs

Network and security infrastructure, such as routers, switches, firewalls, virtual private network concentrators, and other equipment, are designed to provide a stable and secure communications experience for client and server computers and their... Read more »

Examining aspects of encrypted traffic through Zeek logs

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 »

Network security monitoring is dead, and encryption killed it.

This post is part of a multi-part series on encryption and network security monitoring. This post covers a brief history of encryption on the web and investigates the security analysis challenges that have developed as a result. I’ve been hearing... Read more »

Securing the Corelight Sensor

Have you ever considered how security tools can be a source of risk? They process untrusted data 24/7, have access to sensitive flows, and (like everything on the Internet) can be exploited if not patched regularly.   Read more »


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