Dataset from “xDedic” Marketplace Suggests Government, Corporate RDP Servers Targeted

Background

The xDedic marketplace is a predominant cybercriminal marketplace on the dark web known for hosting sales of access to compromised Remote Desktop Protocol (RDP) servers. RDP is Microsoft’s proprietary protocol that provides users with a graphical interface to connect to another computer over a network connection. System administrators frequently use RDP to control servers and PCs remotely. RDP clients are available for all of the modern operating systems (OS), including Linux, Unix, OS X, iOS, and Android. Server software exists for Windows, Unix, and OS X.

In order to gain RDP access, threat actors typically launch bruteforce attacks by systematically checking all possible RDP username and password combinations until a match is found. This primitive form of attacking requires formidable computing power with distributed resources and is most successful against short, weak passwords.

While these attacks tend to be less effective when users’ RDP login credentials include passwords that are longer and more complex, the use of large botnets can enable some attackers to effectively gain RDP access under such circumstances. Indeed, xDedic cybercriminals typically begin launching large-scale scan and bruteforce attacks to collect as much information as possible before sorting its potential value.

As RDP servers are established in order to provide remote access to office resources, they can provide an initial vector into target organizations. Once a hacker secures login credentials for RDP access, he or she effectively owns the system where the RDP server is installed. In addition to being able to launch external attacks and move laterally within networks, attackers are then able to plant malicious software, exfiltrate data, and/or manipulate network settings.

Many actors also sell the login credentials of targeted systems as commodities on underground marketplaces such as xDedic. As the exploitation of RDPs becomes more popular, numerous threat actors continue to inquire about how to properly configure their compromised RDPs to ensure that their illicit activities remain undetected.

Analysis of xDedic Dataset

Flashpoint analysts gained access via an external link to one previously-exposed xDedic dataset, which contained information belonging to over 85,000 servers. The prolific threat actor “thedarkoverlord,” notorious for targeting healthcare entities, is believed to have leveraged this dataset for at least some of their breaches. Indeed, access to open RDPs belonging to healthcare organizations could provide particularly valuable resources to threat actors. Based on Flashpoint’s analysis of the exposed xDedic marketplace data, the most exploited sector appears to be education, followed by healthcare, legal, aviation, and government. The United States, Germany, and Ukraine appear to be the most frequently-targeted countries.

Assessment

Leveraging RDPs is a convenient way to enable access to systems over the Internet, especially in corporate environments that have remote IT support staff. Utilizing RDPs, however, is an organizational risk, given that remote attackers — including the prolific threat actor “xDedic” — may be able to guess or brute force the login credentials.

Moreover, exposing RDPs to the Internet often relies on the presumed lack of a remotely-exploitable vulnerability in the RDP’s implementation. While the abuse of corporate and government RDPs is likely to continue, understanding the criminal tactics, techniques, and procedures (TTPs) listed above can help mitigate attacks from this threat vector.