Dark Reading is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them.Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

Attacks/Breaches

1/30/2019
11:30 AM
50%
50%

Access Control Lists: 6 Key Principles to Keep in Mind

Build them carefully and maintain them rigorously, and ACLs will remain a productive piece of your security infrastructure for generations of hardware to come.
Previous
1 of 8
Next

In an industry of constant, rapid change, an old-school security tool remains an effective piece of an overall security. Access Control Lists (ACLs) that specify precise rules for destinations and protocols allowed or forbidden, are the foundation of firewalls. And while firewalls have advanced to use analysis of packet contents and behavior, ACLs have not gone away.

There are a number of reasons why ACLs endure. The first, and most important, is that they work. ACLs are straight-forward, conceptually simple ways to limit traffic to and from known (or suspected) malicious addresses and to clear traffic to and from addresses known to be acceptable. Next, they play well with others. As Twitter user Frank Barton (@fbarton) wrote in response to a question about ACLs, "…much less cpu intensive than stateful and deep-packet. But…like Ogres, and onions…use layers. If you can block traffic at ACL, then pass remaining to “NGFW” [next-generation firewall] the fw [firewall] has less traffic to inspect."

As with all security measures, though, how an ACL is deployed will have a major impact on its effectiveness. Of course, precisely how the ACL is programmed will vary from manufacturer to manufacturer, and component to component, but there are key considerations that are true regardless of which device is hosting the ACL. Let's take a look at the principles to keep in mind to make ACLs an effective (and efficient) part of the overall security infrastructure.

(Image: photon_photo — stock.adobe.com)

 

Curtis Franklin Jr. is Senior Editor at Dark Reading. In this role he focuses on product and technology coverage for the publication. In addition he works on audio and video programming for Dark Reading and contributes to activities at Interop ITX, Black Hat, INsecurity, and ... View Full Bio

Previous
1 of 8
Next
Comment  | 
Print  | 
More Insights
Comments
Threaded  |  Newest First  |  Oldest First
paul.dittrich
50%
50%
paul.dittrich,
User Rank: Strategist
1/30/2019 | 3:40:31 PM
Harnessing the power of ACLs
I could not agree more strongly with every point in your column.

It may be fashionable to claim there is no longer a network perimeter but I still strongly favor using the border router as a "garbage filter".

The BOGONs list? - Drop them all.  Invalid TCP flag combinations - Drop.  No Telnet in your environment?  No FTP?  No RDP?  - Block them all at the border router.

As mentioned in the post, the NGFW should take care of the deep packet inspection for only the traffic you potentially want inside your network.  That firewall should see very little traffic except for the known IPs, ports and protocols which are candidates to be allowed all the way in.

And an outbound ACL (a.k.a. egress filtering) is a very powerful weapon against data exfiltration and many types of malware.  You may still have a Trojan but if it can't phone home......
Florida Town Pays $600K to Ransomware Operators
Curtis Franklin Jr., Senior Editor at Dark Reading,  6/20/2019
Pledges to Not Pay Ransomware Hit Reality
Robert Lemos, Contributing Writer,  6/21/2019
Register for Dark Reading Newsletters
White Papers
Video
Cartoon
Current Issue
Building and Managing an IT Security Operations Program
As cyber threats grow, many organizations are building security operations centers (SOCs) to improve their defenses. In this Tech Digest you will learn tips on how to get the most out of a SOC in your organization - and what to do if you can't afford to build one.
Flash Poll
The State of IT Operations and Cybersecurity Operations
The State of IT Operations and Cybersecurity Operations
Your enterprise's cyber risk may depend upon the relationship between the IT team and the security team. Heres some insight on what's working and what isn't in the data center.
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2019-12960
PUBLISHED: 2019-06-25
LiveZilla Server before 8.0.1.1 is vulnerable to SQL Injection in functions.internal.build.inc.php via the parameter p_dt_s_d.
CVE-2019-12961
PUBLISHED: 2019-06-25
LiveZilla Server before 8.0.1.1 is vulnerable to CSV Injection in the Export Function.
CVE-2019-12962
PUBLISHED: 2019-06-25
LiveZilla Server before 8.0.1.1 is vulnerable to XSS in mobile/index.php via the Accept-Language HTTP header.
CVE-2019-12963
PUBLISHED: 2019-06-25
LiveZilla Server before 8.0.1.1 is vulnerable to XSS in the chat.php Create Ticket Action.
CVE-2019-12964
PUBLISHED: 2019-06-25
LiveZilla Server before 8.0.1.1 is vulnerable to XSS in the ticket.php Subject.