By: Kevin O’Connor, Director of Threat Research

Key Takeaways

• The Adlumin Threat Research team uncovered a concentrated global campaign employing sophisticated Play ransomware (also identified as PlayCrypt). The campaign is currently targeting mid- market enterprises in the finance, software, legal, and shipping and logistics industries, as well as state, local, tribal and territorial (SLTT) entities in the U.S., Australia, U.K., and Italy. The PlayCrypt ransomware group was previously linked to the City of Oakland attack in March 2023.
• Cybercriminals are directing their efforts towards the managed service providers (MSPs) of these enterprises, utilizing techniques such as remote monitoring and management (RMM) software as vectors or entry points into the targeted systems, which provides complete administrative access.
• Additional attack vectors are Fortinet firewalls with 3–5-year-old vulnerabilities (CVE-2018-13379 and CVE-2020-12812), and other compromised software in the supply chain.
• PlayCrypt ransomware’s code is highly obfuscated and shows strong resistance to typical analysis techniques. Notably, this ransomware group is the first to employ intermittent encryption – a technique that partially encrypts files in chunks of 0x100000 bytes to evade detection.
• This article examines the tactics, techniques, and procedures (TTPs) of threat actors utilizing PlayCrypt, as mapped in the MITRE ATT&CK framework, and observed during an attack and subsequent investigation by the Adlumin MDR and Incident Response Teams.

Initial Access

Last month, in the wee hours of the night, a threat actor used PlayCrypt to leverage Remote Monitoring and Management (RMM) software used by service providers to gain direct access to a customer’s environment, bypassing the majority of its defenses.

RMM software serves as the central nervous system of modern-day service providers. It gives users unfettered, privileged access to networks so operators can deliver seamless support and IT operation functions to a distributed cohort of customers.

But the PlayCrypt ransomware group can utilize the same remote access capability to wreak havoc on mid-market firms.

The ransomware debuted in June 2022 and is strongly affiliated with the Balloonfly malware group. It employs double-extortion tactics, stealing victim data before encrypting their networks.

Recently, PlayCrypt expanded its toolkit with new tools and exploits like ProxyNotShell, OWASSRF, and a Microsoft Exchange Server Remote Code Execution.

Aside from hackers using remote desktop protocol servers as a vector for network infiltration, they can also use FortiOS vulnerabilities (CVE-2018-13379 and CVE-2020-12812), and other compromised software in the supply chain.

In the incident involving PlayCrypt ransomware, Adlumin analysts believe there were at least two potential methods of intrusion. The first possibility is that the hackers gained access through compromised remote desktop software credentials. The second is that they may have exploited a vulnerability in the software itself.

Execution

Once inside the victim’s network, attackers can move quickly to deploy more exploits to gain a solid foothold on the system. These exploits include PowerShell scripts, Microsoft Server Remote Code Execution, and batch files.

Defense Evasion

When exploits have given threat actors root access, they begin creating admin-privileged accounts that can be used to disable security tools. For example, the Adlumin MDR team noticed that hackers utilized the Windows registry to shut down Windows Defender after creating a privileged account.

Adversaries can also replicate the traffic patterns of legitimate users, thereby making it complicated for network security tools to discern between malicious and normal activities.

During the defense evasion stage, threat actors can also delete signs that they are in the system to throw off cybersecurity teams.

Credential Access

To evade detection, threat actors incorporate the use of tools such as Mimikatz to extract credentials. These compromised usernames and passwords are subsequently exploited to escalate privileges, execute lateral movement across the network, and facilitate data exfiltration.

Halting The Attack

The AI-powered Adlumin Security Operations platform was successful in detecting and stopping malicious activity when PlayCrypt ransomware was used. The platform uses automated Security Orchestration Automation and Response (SOAR) actions to isolate impacted endpoints, disable suspicious accounts, reset passwords, initiate scans, and more. As a result of the detections and SOAR actions taken, the MDR team immediately received notifications and started to investigate further and take additional mitigation actions.

During the incident, the MDR team discovered and stopped data exfiltration processes through the FTP port that the hacker had initiated. The team also found malware executables hidden in temporary and system folders.

Command and control (C2) systems activity was also detected. This information allowed an analyst to gather information on the hacker’s location through IP and geolocation.

Finally, analysts found that the hacker(s) also deleted volume shadow copies to prevent the customer from restoring from backups.

Incident Response

Adlumin Incident Response (IR) team joined the investigation to take a deeper dive into the threat actor’s TTPs and examined the malware used through reverse engineering.

The IR team found that PlayCrypt ransomware’s code is highly obfuscated and shows strong resistance to typical analysis techniques. Notably, this ransomware group is the first to employ intermittent encryption – a technique that partially encrypts files in chunks of 0x100000 bytes to evade detection.

Once in a network, threat actors utilize “lolbins” binaries in the ransomware attacks. They distribute executables through Group Policy Objects, employing scheduled tasks, PsExec, or WMIC. Upon achieving full network access, they encrypt files with the “.play” extension.

Recommendations

• Adlumin recommends that customers choose MSPs with strong security records and know-how for identifying and handling data breaches.
• As for MSPs, we recommend the use of stronger credentials and the implementation of multi-factor authentication to prevent threat actors from taking advantage of RMM software.

The Adlumin Advantage

The combination of automated SOAR actions implemented by the Adlumin’s Security Operations Platform and the rapid response of the MDR and Incident Response teams successfully thwarted the attacker’s advances. Had the hacker been successful, they would have held all the customer’s sensitive data hostage through encryption, demanding a ransom.

With the threat neutralized, Adlumin strengthened its defenses, armed with valuable insights from the reversed-engineered PlayCrypt ransomware samples. The IOCs uncovered during the investigation now serve as a robust shield against future attacks, ensuring the protection of customer data and upholding their commitment to cybersecurity excellence.

By: Krystal Rennie, Director of Corporate Communications

In today’s rapidly evolving digital landscape, cyber threats can be identified around every corner, leaving the role of a threat research team to be non-negotiable. Through continuous monitoring, proactive analysis, and timely dissemination of threat intelligence, threat research teams are tasked with fortifying defenses and empowering organizations to stay one step ahead of cyber adversaries.  

In this blog post, we sit down with the Adlumin Threat Research team’s Director, Kevin O’Connor to discuss their pivotal role, shed light on Incident Response, and how the team’s insights are essential in the ongoing battle against cyberthreats. 

Kevin, please tell us more about your team’s role. 

The threat research team works to proactively identify threats that may have bypassed security controls. Another way to think about it is we look for new threats that have yet to be detected. Since they have yet to be detected, there are no rules to protect against these threats, like a specific new type of malware. The Adlumin Threat Research team looks specifically for these undetected threats so we can build defenses to identify those threats in the future.  

We’re also responsible for incident response for our customers. We work with customers when a breach has affected stored data or multiple systems and hasn’t been contained.  The team works with our customers to do complete, end-to-end incident response, identify the root cause, and eliminate the threat.  

Talk to us about the difference between investigation and incident response. 

An investigation analyzes a specific event that might have been triggered by a Managed Detection and Response (MDR) team or MDR software. An investigation looks at a particular event to see if it is malicious in nature, its disposition, and contain the threat from spreading.  

Incident response is the step that comes after an investigation, it includes a deeper dive into the events, additional analysis, potential reverse engineering, and most importantly, eradicating the threat. Then incident response determines the breach’s root cause and overall impact on the business and its assets. It focuses on discovering how the threat got into your network, how long it was there, what it did, and how it bypassed the defenses.  

What are the most common ways that attackers get in and what can customers do to protect themselves?

The most popular way attackers get in is through phishing or spear phishing emails.  

It’s the user who falls victim to these attempts and clicks the malicious link in their inbox that either leads them to a fake login site where they put in their credentials. The attacker can now access the e-mail account and associated productivity tools like OneDrive, Sharepoint and Word, where they can access files or add a malicious file. Or when users open infected attachments sent to them via email, the typical Word Document or PDF with malware is added to kick off the attack. The other half of it is being redirected to sites that then do browser-based exploitation; the attacker exploits your web connection to an accessed link to be able to put malware down on your device, I think those are the two paths within. The human interface between you and the computer results in a lot of exploitation.  

What adversary trends do you think we’ll see in the next year? 

I expect to see more examples of supply chain breaches that lead to compromise.  We saw it earlier with the MOVEit vulnerability, during SolarWinds, and even before that there’s been many examples of commercial software being used to attack the products customers. More advanced malware attackers look at supply chain compromises to enable attacks, especially widespread and against hardened targets.   

What are easy ways to quickly identify if you are being attacked vs being breached? 

It’s important to realize that most organizations are being attacked daily. Those daily attacks might be script kitties, but when we pull up any specific customer and look at their external network perimeter, we see attempts to get into any open services all the time, so the attacks are constant. 

In an attack, you’ll often see many signs of failed entry or exploitation attempts against the customer. So, if you think about an account inside of a customer, let’s say, the billing department, with access to all sorts of financial systems and billing data. And we see repeated phishing emails, maybe all using the same tactic, techniques, and procedure, to get that initial exploitation onto the victim’s machine – that might constitute an attack on your environment. 

Whereas, seeing things like excess connections from a specific host or something trying to reach back to your network is typically a sign of a breach. Other signs are actions taken on the network’s assets, like programs being installed, data being exfiltrated, or settings like security relevant logging being changed.  

What key items should be included in an Incident Response when a breach occurs? 

One of the most important parts that should be included in an Incident Response report is scope. With large-scale breaches, it can quickly reach numerous endpoints within your environment. You’ll need to know what network assets were compromised, what data was compromised, and what access the compromised users/systems have to the data. A timeline of infection and a timeline of exactly what was done, when, and how to contain it is also critical. 

Another key part of the IR report is the root cause analysis that explains how the attackers got into your system so you can close the door and lock it. Time is spent to eradicate the threat and if you don’t close that door the adversary could come back the next day and do the same thing over and over again. Plus, another attacker could also find the same door and exploit it. 

What do you enjoy most about your role?  

I enjoy finding new threats that haven’t been detected before. I love finding a new piece of malware that hasn’t been identified yet. It’s like when a scientist discovers a new animal in the wild. They found a new species of bird or beetle or whatever and get to document exactly how it works, what it does, and how it fits into the ecosystem. There’s a lot of technical investigation involved.  

For example, when we uncovered “PowerDrop,” a malicious PowerShell script that has set its sights on the U.S. aerospace industry, we discovered the malicious malware used advanced techniques to evade detection such as deception, encoding, and encryption. The malware runs remote commands against victim networks after gaining initial access, execution, and persistence into servers.

It’s a big puzzle that you put together, especially when you’re doing reverse engineering, it’s almost like an art and I enjoy it a lot.  

Incident Response and the Adlumin Advantage 

Most IR response firms use third-party tools and deploy it all over the environment to collect information and logs. A core capability of the Adlumin platform is we have insight into all the logs and events for the past three months or more for our customers, so we don’t have to deploy additional technology.  

The events are constantly being saved to a secure source, where attackers can’t really modify them. This is important because if you gather log sources after the attacker has disturbed the environment, the logs may have been poisoned. So, it’s hard to determine the truth. 

Since our agent is already collecting logs and events, even before an incident happens, a lot of the data is already safely stored and logged, which means we can cut down on incident response times and gives customers some savings while giving us an advantage in responding and catching attacks. 

To learn more about Adlumin’s Incident Response offering, download our datasheet today or contact one of our cybersecurity experts for demo.