The Rise of Internet Access Brokers

The Rise of Internet Access Brokers

Researchers from BlackBerry Research & Intelligence Team recently discovered three separate threat groups using the same IT infrastructure maintained by a threat actor dubbed as Zebra2104, which the researchers believe to be an Initial Access Broker.

What Is an Initial Access Broker?

As the name denotes, an Initial Access Broker either buys or sells goods or assets for others. In this case, what is being bought or sold for others is the initial access to the victim’s network.

Once an Initial Access Broker has access to an organization’s network, the broker then advertises this initial access to prospective buyers in the underground forums on the dark web. Initial Access Brokers typically sell access to the victim’s network to the highest bidder on underground forums. The winning bidder then deploys ransomware or other malicious software (malware) to steal or snoop the victim’s critical data.

Initial Access Broker is the first kill chain of many cyberattacks, including ransomware attacks. Initial access to victims’ networks comes in different forms. These include access to vulnerable and internet exposed remote desktop protocol (RDP) and virtual private network (VPN).

VPN, in principle, establishes a protected network connection when using public networks. In the past few years, a number of vulnerabilities have been discovered in many VPN products. RDP, short for remote desktop protocol, is a network communications protocol developed by Microsoft, allowing a computer user to remotely connect to another computer.

In the blog post "Data science for cybersecurity: A probabilistic time series model for detecting RDP inbound brute force attacks", Microsoft Defender Security Research Team said that computers with RDP exposed to the internet are an attractive target for attackers as they offer attackers a simple and effective way to gain access to a network. According to Microsoft Defender Security Research Team, brute-forcing RDP doesn’t need a high level of expertise or the use of exploits.

“RDP connections almost always take place at port 3389, and attackers can assume that this is the port in use and target it to carry out man-in-the-middle attempts, amongst other attacks,” Digital Shadows researchers said in the blog post “Initial Access Brokers In Q3 2021”.

Digital Shadows researchers reported that during the third quarter of 2021, RDP and VPN continued to be the access of choice for Initial Access Brokers. During the third quarter of 2021, the average price for VPN was $1869, while the average price for RDP was $1902. According to Digital Shadows researchers, RDP and VPN were also the most popular access of choice for Initial Access Brokers Q1 and Q2 2021.

“This [popularity of RDP and VPN] is likely due to a combination of the increased use of both technologies as a result of the COVID-19 pandemic and the opportunities afforded to an actor purchasing a VPN or RDP access,” Digital Shadows researchers said.

Digital Shadows researchers added that the VPN-RDP combination – referring to access type that uses VPN access to a victim’s RDP dedicated server – was significantly more expensive in Q3 than the last quarter. “It’s realistically possible that this access type [VPN-RDP] may represent a more secure method of gaining access to targeted networks, and as a result, become more desirable for interested actors,” Digital Shadows researchers said.

Digital Shadows researchers reported that Initial Access Brokers are advertising various accesses to RAMP (Ransom Anon Mark Place), a recently relaunched Russian-language cybercriminal forum.

Zebra2104

In the blog post "Hunter Becomes Hunted: Zebra2104 Hides a Herd of Malware", BlackBerry researchers said they uncovered a connection between the criminal activities of three distinct threat groups, MountLocker, Phobos, and StrongPity. “While it might seem implausible for criminal groups to be sharing resources, we found these groups [MountLocker, Phobos, and StrongPity] had a connection that is enabled by a fourth; a threat actor we have dubbed Zebra2104, which we believe to be an Initial Access Broker (IAB),” BlackBerry researchers said.

MountLocker is a ransomware group that has been active since July of 2020. Phobos is another ransomware group that was first seen in early 2019. Phobos has been victimizing small-to-medium-sized organizations across a variety of industries. StrongPity, also known as Promethium, is an espionage group that has been active since at least 2012.

According to BlackBerry researchers, a single domain led them down a path where they uncovered multiple ransomware attacks by MountLocker, Phobos, and a command-and-control (C2) of StrongPity. “The path also revealed what we believe to be the infrastructure of an IAB: Zebra2104,” BlackBerry researchers said.

Cybersecurity Best Practices

Cybercrime groups nowadays mimic multinational organizations’ business models. Similar to multinational organizations, cybercrime groups establish partnerships and alliances with other organizations, in this case, with Initial Access Brokers.

Considering that RDP and VPN are the popular initial accesses, it’s important to guard these two gateways. Here are some of the best practices to guard RDP and VPN:

• Keep operating systems and VPN up to date. For instance, in the past, Microsoft included in its updates patches to known vulnerabilities of RDP. VPN vendors, meanwhile, have released patches to known vulnerabilities to their VPN products.
• Use strong passwords for RDP and VPN.
• Use multi-factor authentication (MFA) for RDP and VPN to add an extra layer of protection in addition to a mere password.
• Practice network segmentation. In network segmentation, your organization’s network is subdivided into subnetworks. Organizations that use VPN access to RDP dedicated server benefit by separating this subnetwork from the other critical subnetworks. In a segmented network, criminals who have already compromised an internet-exposed VPN-RDP will be prevented from escalating their malicious activities to other critical subnetworks.