Category Archives: Security

Explain Cisco ETA to Me in a Way That Even My Neighbor Can Understand It

Cisco Encrypted Traffic Analytics (ETA) sounds just a little bit like magic the first time you hear about it. Cisco is basically proposing that when you turn on ETA, your network can (magically!) detect malicious traffic (ie, malware, trojans, ransomware, etc) inside encrypted flows. Further, Cisco proposes that ETA can differentiate legitimate encrypted traffic from malicious encrypted traffic.

Uhmm, how?

The immediate mental model that springs to mind is that of a web proxy that intercepts HTTP traffic. In order to intercept TLS-encrypted HTTPS traffic, there’s a complicated dance that has to happen around building a Certificate Authority, distributing the CA’s public certificate to every device that will connect through the proxy and then actually configuring the endpoints and/or network to push the HTTPS traffic to the proxy. This is often referred to as “man-in-the-middle” (MiTM) because the proxy actually breaks into the encrypted session between the client and the server. In the end, the proxy has access to the clear-text communication.

Is ETA using a similar method and breaking into the encrypted session?

In this article, I’m going to use an analogy to describe how ETA does what it does. Afterwards, you should feel more comfortable about how ETA works and not be worried about any magic taking place in your network. 🧙

Continue reading Explain Cisco ETA to Me in a Way That Even My Neighbor Can Understand It

So Your Username and Password Where in a Data Dump. Now What?

Whether it’s Dropbox, LinkedIn, MySpace, PlayStation, or whatever the latest breach happens to be, it’s almost inevitable that you will be caught up in one of these breaches and have your username, password and possibly other information exposed in a data dump. Here’s how to respond when that happens. Continue reading So Your Username and Password Where in a Data Dump. Now What?

Auto Renew Let’s Encrypt Certificates

I’m a big fan of Let’s Encrypt (free, widely trusted SSL certificates) but not a big fan of most of the client software available for requesting and renewing certificates. Unlike a typical certificate authority, Let’s Encrypt doesn’t have a webui for requesting/renewing certs; everything is driven via an automated process that is run between a Let’s Encrypt software client and the Let’s Encrypt web service.

Since the protocols that Let’s Encrypt uses are standards-based, there are many open source clients available. Being security conscious, I have a few concerns with most of the clients:

  • Complication. Many of the clients are hundreds of lines long and unnecessarily complicated. This makes the code really hard to audit and since this code is playing with my crypto key material, I do want to audit it.
  • Elevated privilege. At least one of the clients I saw required root permission. That’s a non starter.

Continue reading Auto Renew Let’s Encrypt Certificates

Getting Traffic to a Virtual Firepower Sensor

I wanted to jot down some quick notes relating to running a virtual Firepower sensor on ESXi and how to validate that all the settings are correct for getting traffic from the physical network down into the sensor.

Firepower is the name of Cisco’s (formerly Sourcefire’s) so-called Next-Gen IPS. The IPS comes in many form-factors, including beefy physical appliances, integrated into the ASA firewall, and as a discrete virtual machine.

Since the virtual machine (likely) does not sit in-line of the traffic that needs to be monitored, traffic needs to be fed into the VM via some method such as a SPAN port or a tap of some sort.

Continue reading Getting Traffic to a Virtual Firepower Sensor

BRKSEC-2010: Emerging Threats – The State of Cyber Security

Presenter: Craig Williams (@security_craig) – Sr Technical Leader / Security Outreach Manager, Cisco TALOS

I’m from Talos. We love to stop bad guys.

 
Talos by the numbers:

  • 1.1 million incoming malware samples per day
  • 1.5 billion Sender Base reputation queries per day

Talos has a serious amount of data. For serious.
Continue reading BRKSEC-2010: Emerging Threats – The State of Cyber Security

VPN Host Checker vs. AD Group Policy

This post is for anyone who administers a Juniper SSL VPN. I saw an issue in our environment recently that was created by an unexpected interaction between two different systems that were working to enforce our computer security policy. Because the way the systems were configured is pretty common and because the issue is not specifically warned against by Juniper, I’m going to share it here.

Continue reading VPN Host Checker vs. AD Group Policy