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

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.
2 of 8

ACLs Everywhere
Think of the network interface that you'd like to use as the portal for inviting criminal hackers to steal your company IP and your customer PII. Good - that's the interface that you don't want to protect with an ACL
In virtually every piece of security or routing gear, ACLs are applied individually on each interface. That makes complete sense, because you don't want to have the same rules for outward-facing interfaces and those that make up your campus network. But the differences between interfaces are not so great that you want some protected by ACLs and some left bare.
This practice of an ACL on every interface is critical for inbound ACLs - those rules that govern which addresses can send data into your network. Those are the rules that make the biggest, most immediate, difference. With that in mind, though, it's important to remember that ACLs go both ways.
(Image: Chris Titze Imaging - stock.adobe.com)

ACLs Everywhere

Think of the network interface that you'd like to use as the portal for inviting criminal hackers to steal your company IP and your customer PII. Good that's the interface that you don't want to protect with an ACL

In virtually every piece of security or routing gear, ACLs are applied individually on each interface. That makes complete sense, because you don't want to have the same rules for outward-facing interfaces and those that make up your campus network. But the differences between interfaces are not so great that you want some protected by ACLs and some left bare.

This practice of an ACL on every interface is critical for inbound ACLs those rules that govern which addresses can send data into your network. Those are the rules that make the biggest, most immediate, difference. With that in mind, though, it's important to remember that ACLs go both ways.

(Image: Chris Titze Imaging stock.adobe.com)

2 of 8
Comment  | 
Print  | 
Comments
Newest First  |  Oldest First  |  Threaded View
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......
US Turning Up the Heat on North Korea's Cyber Threat Operations
Jai Vijayan, Contributing Writer,  9/16/2019
MITRE Releases 2019 List of Top 25 Software Weaknesses
Kelly Sheridan, Staff Editor, Dark Reading,  9/17/2019
Register for Dark Reading Newsletters
White Papers
Video
Cartoon Contest
Write a Caption, Win a Starbucks Card! Click Here
Latest Comment: "He's too shy to invite me out face to face!"
Current Issue
7 Threats & Disruptive Forces Changing the Face of Cybersecurity
This Dark Reading Tech Digest gives an in-depth look at the biggest emerging threats and disruptive forces that are changing the face of cybersecurity today.
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-2019-16649
PUBLISHED: 2019-09-21
On Supermicro H11, H12, M11, X9, X10, and X11 products, a combination of encryption and authentication problems in the virtual media service allows capture of BMC credentials and data transferred over virtual media devices. Attackers can use captured credentials to connect virtual USB devices to the...
CVE-2019-16650
PUBLISHED: 2019-09-21
On Supermicro X10 and X11 products, a client's access privileges may be transferred to a different client that later has the same socket file descriptor number. In opportunistic circumstances, an attacker can simply connect to the virtual media service, and then connect virtual USB devices to the se...
CVE-2019-15138
PUBLISHED: 2019-09-20
The html-pdf package 2.2.0 for Node.js has an arbitrary file read vulnerability via an HTML file that uses XMLHttpRequest to access a file:/// URL.
CVE-2019-6145
PUBLISHED: 2019-09-20
Forcepoint VPN Client for Windows versions lower than 6.6.1 have an unquoted search path vulnerability. This enables local privilege escalation to SYSTEM user. By default, only local administrators can write executables to the vulnerable directories. Forcepoint thanks Peleg Hadar of SafeBreach Labs ...
CVE-2019-6649
PUBLISHED: 2019-09-20
F5 BIG-IP 15.0.0, 14.1.0-14.1.0.6, 14.0.0-14.0.0.5, 13.0.0-13.1.1.5, 12.1.0-12.1.4.1, 11.6.0-11.6.4, and 11.5.1-11.5.9 and Enterprise Manager 3.1.1 may expose sensitive information and allow the system configuration to be modified when using non-default ConfigSync settings.