Here’s Why You Don’t Want RDP on the Internet

For those of you that are unfamiliar with the HITME project, it is a set of deployed HoneyPoints that gather real-world, real-time attacker data from around the world. The sensors gather attack sources, frequency, targeting information, vulnerability patterns, exploits, malware and other crucial event data for the technical team at MSI to analyze. We frequently feed these attack signatures into our vulnerability management service to ensure that our customers are tested against the most current forms of attacks being used on the Internet.

It’s also important that we take a step back and look at our HITME data from a bird’s-eye view to find common attack patterns. This allows us to give our customers a preemptive warning in the event that we identify a significant increase in a specific threat activity. We recently analyzed  some of the data that we collected during the month of November. We found that over 47% of the observed attacks in the public data set were against the Remote Desktop Protocol (RDP)(often also known as Microsoft Terminal Services). This was more than attacks against web servers, telnet servers and FTP servers combined!

Be sure that all recommended security measures are applied to RDP systems. This should include requiring the use of RDP clients that leverage high levels of encryption. If you need any assistance verifying that you are protected against attacks against your terminal servers, feel free to contact us by sending an email to info(at)microsolved(dot)com.

This post by Adam Luck.

Terminal Services Attack Reductions Redux

Last week, we published a post about the high frequency of probes, scans and attacks against exposed Windows Terminal Services from the Internet. Many folks commented on Twitter to me about some of the things that can be done to minimize the risk of these exposures. As we indicated in the previous post, the best suggestions are to eliminate them altogether by placing Terminal Services exposures behind VPN connections or through the implementation of tokens/multi-factor authentication. 

Another idea is to implement specific firewall rules that block access to all but a specific set of IP addresses (such as the home IP address range of your admins or that of a specific jump host, etc.) This can go a long way to minimizing the frequency of interaction with the attack surfaces by random attacker tools, probes and scans. It also raises the bar slightly for more focused attackers by forcing them to target specific systems (where you can deploy increased monitoring).

In addition, a new tool for auditing the configuration of Terminal Services implementations came to our attention. This tool, called “rdp-sec-check”, was written by Portcullis Security and is available to the public. Our testing of the tool showed it to be quite useful in determining the configuration of exposed Terminal Services and in creating a path for hardening them wherever deployed. (Keep in mind, it is likely useful to harden the Terminal Services implementations internally to critical systems as well…)

Note that we particularly loved that the tool could be used REMOTELY. This makes it useful to audit multiple customer implementations, as well as to check RDP exposures during penetration testing engagements. 

Thanks to Portcullis for making this tool available. Hopefully between this tool to harden your deployments and our advice to minimize the exposures, we can all drive down some of the compromises and breaches that result from poor RDP implementations.

If you would like to create some threat metrics for what port 3389 Terminal Services exposures might look like for your organization, get in touch and we can discuss either metrics from the HITME or how to use HoneyPoint to gather such metrics for yourself

PS – Special thanks to @SecRunner for pointing out that many cloud hosting providers make Terminal Server available with default configurations when provisioning cloud systems in an ad-hoc manner. This is likely a HUGE cause for concern and may be what is keeping scans and probes for 3389/TCP so active, particularly amongst cloud-hosted HITME end points.

PSS – We also thought you might enjoy seeing a sample of the videos that show entry level attackers exactly how to crack weak passwords via Terminal Services using tools easily available on the Internet. These kinds of videos are common for low hanging fruit attack vectors. This video was randomly pulled from the Twitter stream with a search. We did not make it and are not responsible for its content. It may not be safe for work (NSFW), depending on your organization’s policies. 


Exposed Terminal Services Remains High Frequency Threat

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Quickly reviewing the HITME data gathered from our global deployment of HoneyPoint continues to show that exposed Terminal Services (RDP) on port 3389 remains a high frequency threat. In terms of general contact with the attack surface of an exposed Terminal Server connection, direct probes and attacker interaction is seen on an average approximately two times per hour. Given that metric, an organization who is using exposed Terminal Services for remote access or management/support, may be experiencing upwards of 48 attacks per day against their exposed remote access tool. In many cases, when we conduct penetration testing of organizations using Terminal Services in this manner, remote compromise of that service is found to lead to high levels of access to the organization’s data, if not complete control of their systems.

Many organizations continue to use Terminal Services without tokens or VPN technologies in play. These organizations are usually solely dependent on the security of login/password combinations (which history shows to be a critical mistake) and the overall security of the Terminal Services code (which despite a few critical issues, has a pretty fair record given its wide usage and intense scrutiny over the last decade). Clearly, deploying remote access and remote management tools is greatly preferred behind VPN implementations or other forms of access control. Additionally, upping Terminal Services authentication controls by requiring tokens or certificates is also highly suggested. Removing port 3389 exposures to the Internet will go a long way to increasing the security of organizations dependent on RDP technology.

If you would like to discuss the metrics around port 3389 attacks in more detail, drop us a line or reach out on Twitter (@microsolved). You can also see some real time metrics gathered from the HITME by following @honeypoint on Twitter. You’ll see lots of 3389 scan and probe sources in the data stream.

Thanks for reading and until next time, stay safe out there!