{"id":4209,"date":"2019-12-18T12:02:50","date_gmt":"2019-12-18T10:02:50","guid":{"rendered":"https:\/\/blog.eset.ee\/?p=4209"},"modified":"2019-12-18T12:03:14","modified_gmt":"2019-12-18T10:03:14","slug":"its-time-to-disconnect-rdp-from-the-internet","status":"publish","type":"post","link":"https:\/\/blog.eset.ee\/et\/en\/2019\/12\/18\/its-time-to-disconnect-rdp-from-the-internet\/","title":{"rendered":"It\u2019s time to disconnect RDP from the internet"},"content":{"rendered":"\n

While the BlueKeep (CVE-2019-0708<\/a>) vulnerability has not, to date, caused widespread havoc, and we will be looking at the reasons why in this post, it is still very early in its exploitation life cycle. The fact remains that many systems are still not patched, and a thoroughly wormable<\/a> version of the exploit might still be found. Because of these factors, ESET has created a free utility to check if a system is vulnerable.<\/p>\n\n\n\n

ESET BlueKeep (CVE-2019-0708) Detection Tool<\/a><\/p>\n\n\n\n

Download tool
<\/a><\/p>\n\n\n\n

Sometimes, you have to say something about things that \u201cgo without saying\u201d and it seems the best way to start this post is by mentioning just that, because this is not a subject I expected to have to write about in this day and age. Before we dive in, let\u2019s begin by looking at an old maxim.<\/p>\n\n\n\n

There is an old saying in the information security field that if an adversary has physical access to your computer then it is not your computer anymore. The reason for this is quite simple: once the attackers have their hands on a computer, they can change anything they want. Installing devices such as hardware keyloggers, removing disk drives and copying them, and otherwise deleting, altering or adding anything they want on the system all become exponentially easier when you can walk right up to the computer. This is not a particularly surprising turn of events, nor a particularly clever one. Rather, it is an unavoidable truth. For the adversaries, it\u2019s just part of their job description.<\/p>\n\n\n\n

Businesses and schools and all sorts of organizations are not blind to this, though. None of these kinds of places put their servers at the front desk in the lobby, reception area, visitor center, waiting room or other locations where the public or, conceivably, any employee, faculty, student, or staff may enter and gain physical access to them. Or, at least, no business that wants to remain in business allows this. Usually, there\u2019s some separation of the servers, whether they be in their own dedicated room, or even tucked away in some back corner that is off-limits to most personnel.<\/p>\n\n\n\n

Yet for all this common knowledge, the lessons learned about security in the physical world do not always transfer well (or correctly) into the internet world. There are a large number of servers running various versions of Microsoft Windows server operating systems that are directly connected to the internet with what amounts to little or no practical security around who can access them. And that brings us to the discussion of RDP.<\/p>\n\n\n\n

What is RDP?<\/h2>\n\n\n\n

RDP, short for Remote Desktop Protocol, allows one computer to connect to another computer over a network in order to use it remotely. In a domain, computers running a Windows Client operating system, such as Windows XP or Windows 10 come with RDP client software preinstalled as part of the operating system, which allows them to connect to other computers on the network, including the organization\u2019s server(s). A connection to a server in this case means it could<\/em> be directly to the server\u2019s operating system, or it could be to an operating system running inside a virtual machine on that server. From that connection, a person can open directories, download and upload files, and run programs, just as if they were using the keyboard and monitor connected to that server.<\/p>\n\n\n\n

RDP was invented by Citrix in 1995 and sold as part of an enhanced version of Windows NT 3.51 called WinFrame. In 1998, Microsoft added RDP to Windows NT 4.0 Terminal Server Edition<\/a>. Since then, the protocol has been a part of all versions of Microsoft\u2019s line of Windows Server operating systems, as well as being included with all non-home user editions of Windows Client operating systems since Windows XP was released in 2001. Today, common users of RDP include system administrators doing remote administration of servers from their cubicles without having to go into the server room, as well as remote workers who can connect to virtualized desktop machines inside their organization\u2019s domain.<\/p>\n\n\n\n

What do attackers do with RDP?<\/h2>\n\n\n\n

For the past couple of years, ESET has seen an increasing number of incidents where the attackers have connected remotely to a Windows Server from the internet using RDP and logged on as the computer\u2019s administrator. Once the attackers are logged into the server as administrator, they will typically perform some reconnaissance to determine what the server is used for, by whom, and when it is being used.<\/p>\n\n\n\n

Once the attackers know the kind of server they have control of, they can begin performing malicious actions. Common malicious activities we have seen include:<\/p>\n\n\n\n