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Let’s Put Down Insecure Protocols For Good


Insecure Service Protocols and Ports

Okay, we all have them… they’re everyone’s dirty little network security secrets that we try not to talk about. They’re the protocols that we don’t mention in a security audit or to other people in the industry for fear that we’ll be publicly embarrassed. Yes, I’m talking about cleartext protocols which are running rampant across many networks. They’re in place because they work, and they work well, so no one has had a reason to upgrade them. Why upgrade something if it’s working right? Wrong. These protocols need to go the way of records, 8-tracks and cassettes (many of these protocols were fittingly developed during the same era). You’re putting your business and data at serious risk by running these insecure protocols.

There are many insecure protocols that are exposing your data in cleartext, but let’s focus on the three most widely used ones: FTP, Telnet and SNMP.

FTP (File Transfer Protocol)

This is by far the most popular of the insecure protocols in use today. It’s the king of all cleartext protocols and one that needs to be smitten from your network before it’s too late. The problem with FTP is that all authentication is done in cleartext which leaves little room for the security of your data. To put things into perspective, FTP was first released in 1971, almost 45 years ago. In 1971 the price of gas was 40 cents a gallon, Disneyland had just opened and a company called FedEx was established. People, this was a long time ago. You need to migrate from FTP and start using an updated and more secure method for file transfers, such as HTTPS, SFTP or FTPS. These three protocols use encryption on the wire and during authentication to secure the transfer of files and login.


If FTP is the king of all insecure file transfer protocols then telnet is supreme ruler of all cleartext network terminal protocols. Just like FTP, telnet was one of the first protocols that allowed you to remotely administer equipment. It became the defacto standard until it was discovered that it passes authentication using cleartext.

At this point you need to hunt down all equipment that is still running telnet and replace it with SSH, which uses encryption to protect authentication and data transfer. This shouldn’t be a huge change unless your gear cannot support SSH. Many appliances or networking gear running telnet will either need the service enabled or the OS upgraded. If both of these options are not appropriate, you need to get new equipment, case closed. I know money is an issue at times, but if you’re running a 45 year old protocol on your network with the inability to update it, you need to rethink your priorities. The last thing you want is an attacker gaining control of your network via telnet. Its game over at this point.

SNMP (Simple Network Management Protocol)

This is one of those sneaky protocols that you don’t think is going to rear its ugly head and bite you, but it can!

There are multiple versions of SNMP, and you need to be particularly careful with versions 1 and 2. For those not familiar with SNMP, it’s a protocol that enables the management and monitoring of remote systems. Once again, the strings can be sent via cleartext, and if you have access to these credentials you can connect to the system and start gaining a foothold on the network, including managing, applying new configurations or gaining in-depth monitoring details of the network. In short, it a great help for attackers if they can get hold of these credentials.

Luckily version 3.0 of SNMP has enhanced security that protects you from these types of attacks. So you must review your network and make sure that SNMP v1 and v2 are not being used.

These are just three of the more popular but insecure protocols that are still in heavy use across many networks today. By performing an audit of your firewalls and systems to identify these protocols, preferably using an automated tool such as AlgoSec Firewall Analyzer, you should be able to pretty quickly create a list of these protocols in use across your network. It’s also important to proactively analyze every change to your firewall policy (again preferably with an automated tool for security change management) to make sure no one introduces insecure protocol access without proper visibility and approval.

Finally, don’t feel bad telling a vendor or client that you won’t send data using these protocols. If they’re making you use them, there’s a good chance that there are other security issues going on in their network that you should be concerned about. It’s time to get rid of these protocols. They’ve had their usefulness, but the time has come for them to be sunset for good.

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