Top 10 Network Vulnerabilities Inside the Network

Today's state-of-the-art network security appliances do a great job of keeping the cyber monsters from invading your business. But what do you do when the monster is actually inside the security perimeter? Unfortunately, all of the crosses, garlic, wooden stakes and silver bullets in the world have little effect on today's most nefarious cyber creatures. Here are the top 10 ways your network can be attacked from inside and what you can do to insure your business never has to perform an exorcism on your servers.

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1. USB thumb drives: Believe it or not, USB drives are actually one of, if not the most, common ways you can infect a network from inside a firewall. There are several reasons for this; they're inexpensive, small, hold a lot of data and can be used between multiple computer types. The ubiquity of thumb drives has driven hackers to develop targeted malware, such as the notorious Conficker worm, that can automatically execute upon connecting with a live USB port. What's worse is that default operating system configurations typically allow most programs (including malicious ones) to run automatically. That's the equivalent of everyone in your neighborhood having an electric garage door opener and being able to use it to open everyone else's garage doors.

What to do: Change the computer's default autorun policies. You can find information on how do that within Windows environments here.

2. Laptop and netbooks: Laptops are discreet, portable, include full operating systems, can operate using an internal battery and come with a handy Ethernet port for tapping directly into a network. What's more, a notebook may already have malicious code running in the background that is tasked to scour the network and find additional systems to infect. This notebook could belong to an internal employee or guest who's visiting and working from an open cube or office.

Beyond infected laptops compromising an internal network, it's important to think about the laptops themselves. All companies have some forms of sensitive information that absolutely cannot leave the walls of the building (salary information, medical records, home addresses, phone numbers and Social Security numbers are just a few obvious examples). It becomes very dangerous when that information is stored on an unsecured portable computer, as they are easy to walk off with. We've seen numerous, publicly disclosed instances of notebooks with sensitive data that have "gone missing." Unless the laptop employs a tough encryption algorithm, data is often easy to recover from any given file system.

What to do: Implement an encrypted file system for sensitive data. There are a number of off-the-shelf solutions out there to choose from, along with open source ones such as TrueCrypt. Control over endpoints that enter and exit the internal system is also important. Sensitive information, such as VPN, DV and Wi-Fi access should not be stored persistently on devices such as laptops or netbooks.

3. Wireless access points: Wireless APs provide immediate connectivity to any user within proximity of the network. Wireless attacks by wardrivers (people in vehicles searching for unsecured Wi-Fi networks) are common and have caused significant damage in the past. TJ Stores, owners of Marshalls and TJMaxx, was attacked using this method, and intruders penetrated the company's computer systems that process and store customer transactions including credit card, debit card, check and merchandise return transactions. It's been reported that this intrusion has cost TJ Stores more than $500 million dollars to date.

Wireless APs are naturally insecure, regardless if encryption is used or not. Protocols such as wireless encryption protocol contain known vulnerabilities that are easily compromised with attack frameworks, such as Aircrack. More robust protocols such as wireless protected access (WPA) and WPA2 are still prone to dictionary attacks if strong keys are not used.

What to do: WPA2 Enterprise using RADIUS is recommended along with an AP that is capable of performing authentication and enforcing security measures. Strong, mixed passwords should be used and changed on a fairly frequent basis. Generally, wireless APs are connected for convenience, so it is usually not necessary to have them connected to a working environment.

4. Miscellaneous USB devices: Thumb drives aren't the only USB-connected devices IT needs to be wary of. Many devices are also capable of storing data on common file systems that can be read and written to through a USB or similar connection. Since it isn't the primary function of these devices, they are often forgotten as a potential threat. The fact is, if an endpoint can read and execute data from the device, it can pose just as much of a threat as a thumb drive. These devices include digital cameras, MP3 players, printers, scanners, fax machines and even digital picture frames. In 2008, Best Buy reported that they found a virus in the Insignia picture frames they were selling at Christmas that came directly from the manufacturer.

What to do: Implement and enforce asset control and policies around what devices can enter the environment and when. And then follow that up with frequent policy reminders. In 2008, the Department of Defense developed policies and banned USB and other removable media from entering/exiting their environments.

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