John Marrett

John is Stack8's Director of Managed Services. John specializes in network and security, by developing innovative solutions for our clients and providing them with ongoing support.

Recent Posts

Networking Segmentation for Security using VRF

Posted by John Marrett on Apr 7, 2016 9:08:56 AM

Many organisations today face a challenge in securing enterprise networks that were designed prior to internal segmentation and security becoming a primary concern. It is very difficult to retrofit security into a network design, especially when you want to avoid changing server configurations, minimize downtime and impact, maintain performance within existing network segments, and progressively phase in security rules. In this blog post, we'll discuss an approach we have developed and used for both new network deployments, as well as, retrofits. 

THE PROBLEM

Retrofitting security into a network design while avoiding server configuration changes, downtime and performance issues.

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Topics: Security, Network & Security Insights, How to(s)

CVE-2015-7547, glibc vulnerability; its impact on Cisco products and our mitigation solutions

Posted by John Marrett on Feb 19, 2016 12:16:06 PM

 

 

The Vulnerability 

On Tuesday, February 16th, Google's security team announced a significant vulnerability in glibc . The vulnerability relates to the handling of DNS packets, and many Cisco systems are vulnerable to it if an attacker can cause an affected device to perform a DNS lookup against an attacker-controlled DNS server. As many services (ssh, some web servers, mail servers) do perform these requests in an externally controllable fashion, the risk and exposure of this vulnerability are extremely significant.

Cisco released their advisory for this issue on the 18th. Because of the extensive use of Linux in newer switching and routing products, UC servers, and security and management appliances, the potential scope of the issue is vast. Cisco is presently still in the process of qualifying products to determine if and how they are affected.

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Topics: Security, Network & Security Insights, Network

Cisco CVE-2016-1287 Network Vulnerability and our Mitigation Solution

Posted by John Marrett on Feb 11, 2016 11:37:47 AM


CISCO CVE-2016-1287 VULNERABILITY PROBLEM

Yesterday Cisco released an out of band patch for an ASA vulnerability (CVE-2016-1287) that permits remote code execution for any ASA device enabled for IKE / IPSec.
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160210-asa-ike

You can validate if your configuration is affected using the following command:

show run crypto map | include interface

The Cisco advisory indicates that there is no way to mitigate this threat. There are a large number of  vulnerable ASA firmware versions that have not and will not receive fixes. Customers should be aware of the difficulty in migrating from 8.2 to newer versions because of the complete restructuring of NAT rules.

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Topics: Security, Network & Security Insights, Cisco Release Notes and Product Reviews, Network

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