Cisco WSA Acceptable Use and HTTPS inspection

In this and other posts we’ll discuss the Cisco Web Security Appliance. This is the blog agenda:
Part 1: Introduction
Part 2: Installing
Part 3: Deploying Proxy Services
Part 4: Policies
Part 5: Acceptable use & HTTPS Inspection
Part 6: Authentication
Part 7: Defending malware
This is the 5th part of the series
How can you enforce the Acceptable use?
Acceptable use is mostly defined by Application Visibility Control (AVC). Websites are classified by a URL lookup in the cisco database, based on the URL itself, or a dynamic scan of the website.
To configure this, click Security Services > Acceptable Use Controls
avc
AVC is enabled by default.
HTTPS Inspection (HTTPS Proxy)
It’s getting more important to decrypt HTTPS sessions to check against your policies. You can receive a lot of nasty stuff inside your HTTPS session. But there is one major drawback: the WSA shows the user a SSL certificate of the WSA appliance. In almost all circumstances this certificate wouldn’t match all requirements, so the users receive SSL certificate errors. Make sure your users are familiar with your HTTPS inspection!
How does it works? It’s pretty simple: the WSA creates the HTTPS session to the webserver and creates a new HTTPS session to the user. The responses from the webserver are checked and scanned and deliverd over the new HTTPS session to the user.
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Cisco WSA Deploying Proxy Services

In this and other posts we’ll discuss the Cisco Web Security Appliance. This is the blog agenda:
Part 1: Introduction
Part 2: Installing
Part 3: Deploying Proxy Services
Part 4: Policies
Part 5: Acceptable use & HTTPS Inspection
Part 6: Authentication
Part 7: Defending malware
This is the 3th blog in the series about the proxy configuration.
There are a two proxy modes:

  • Explicit Forward Mode
  • Transparent Mode

In Explicit Forward Mode the client does have an Proxy configuration. There is no configuration needed on the network infrastructure (routers/switches). Authentication is easy and there are three methods for providing the proxy information:

  • Automatic Proxy script
  • Enter the proxy server IP address
  • Automatic detect settings using WPAD protocol

In transparent mode, there is no configuration needed on the clients. The network infrastructure redirects the traffic (WCCP). Authentication could be an issue.
Redirection options are:

  • Web Cache control protocol (WCCP, used in Cisco ASA, ASR and Catalyst switches)
  • Policy based routing
  • Layer 4 switch
  • Layer 7 switch (like a Citrix Netscaler)

WCCP is the most used redirection option for transparant proxies. For more information about WCCP and the configuration, check this link.
PAC files
PAC files are used in Explicit Forward Mode. The PAC file link is configured on the clients’ proxy settings. If you need help with creating PAC files, check this link.
You can host the PAC file on any webserver, but hosting on the WSA is possible too. Click Security Services > PAC File Hosting¬† and upload your PAC file. It’s recommended to host the PAC file on a seperate web server.
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Cisco Web Security Appliance introduction

In this and upcoming posts we’ll discuss the Cisco Web Security Appliance. This is the blog agenda for the upcoming weeks:
Part 1: Introduction
Part 2: Installing
Part 3: Deploying Proxy Services
Part 4: Policies
Part 5: Acceptable use & HTTPS Inspection
Part 6: Authentication
Part 7: Defending malware
In this blog we’ll talk about the product introduction.
The Cisco Web Security Appliance (WSA) is an appliance for securing http, https and ftp traffic from (and to) the internet.
The WSA replaces all, or most of these devices in your network:
Firewall
Webproxy
Anti spyware
Antivirus
URL Filtering
Policy management
As you can see, it’s more than just a regular proxy server.
The internet provides a lot of websites, good websites and bad websites. There are a lot of websites which are not work related for a lot of companies. If you want to limit or block those websites for users, the WSA is the product for you. Limitation can be time based, bandwidth based, user based or category based (79 categories). Road warriors (remote users) can be protected too by Anyconnect security or Web cloud Security, also known as Scansafe.
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