Security Mistakes That Leave You Vulnerable To Compromise #4: Internet Access For Servers


Can your internal servers reach the Internet?  File servers, database servers and others that potentially store valuable information are often allowed access to the Internet, but there’s no good reason they should.  The ability to do so just gives your attackers an easy way to steal your data. If an attacker gains access to a server, he can simply send the stolen data right out of your network.

By blocking Internet access for your servers, you block that escape path and force the attacker to move the data somewhere else, leaving a trail of information that will give away his presence.  The attacker will need to copy data to other workstations in order to steal it. This will give you an opportunity to detect the data transfer and take appropriate action.  In addition, if you log Internet attempts from your servers, those log entries will be an indicator that something is amiss in your network.

If you have servers that need to communicate with the Internet, such as mail or web servers, they belong in a DMZ.

If you need Internet access to download software updates or patches, download them to an administrator’s workstation, and install from there.

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Nick Kelly

Cybersecurity Engineer, Cisco

Nick has over 20 years of experience in Security Operations and Security Sales. He is an avid student of cybersecurity and regularly engages with the Infosec community at events like BSides, RVASec, Derbycon and more. The son of an FBI forensics director, Nick holds a B.S. in Criminal Justice and is one of Cisco’s Fire Jumper Elite members. When he’s not working, he writes cyberpunk and punches aliens on his Playstation.


Virgilio “BONG” dela Cruz Jr.

CCDP, CCNA V, CCNP, Cisco IPS Express Security for AM/EE
Field Solutions Architect, Tech Data

Virgilio “Bong” has sixteen years of professional experience in IT industry from academe, technical and customer support, pre-sales, post sales, project management, training and enablement. He has worked in Cisco Technical Assistance Center (TAC) as a member of the WAN and LAN Switching team. Bong now works for Tech Data as the Field Solutions Architect with a focus on Cisco Security and holds a few Cisco certifications including Fire Jumper Elite.


John Cavanaugh

CCIE #1066, CCDE #20070002, CCAr
Chief Technology Officer, Practice Lead Security Services, NetCraftsmen

John is our CTO and the practice lead for a talented team of consultants focused on designing and delivering scalable and secure infrastructure solutions to customers across multiple industry verticals and technologies. Previously he has held several positions including Executive Director/Chief Architect for Global Network Services at JPMorgan Chase. In that capacity, he led a team managing network architecture and services.  Prior to his role at JPMorgan Chase, John was a Distinguished Engineer at Cisco working across a number of verticals including Higher Education, Finance, Retail, Government, and Health Care.

He is an expert in working with groups to identify business needs, and align technology strategies to enable business strategies, building in agility and scalability to allow for future changes. John is experienced in the architecture and design of highly available, secure, network infrastructure and data centers, and has worked on projects worldwide. He has worked in both the business and regulatory environments for the design and deployment of complex IT infrastructures.