Over the past week we have seen a considerable body of work focusing on DarkSide, the ransomware responsible for the recent gas pipeline shutdown. Many of the excellent technical write-ups will detail how it operates an affiliate model that supports others to be involved within the ransomware business model (in addition to the developers). While this may not be a new phenomenon, this model is actively deployed by many groups with great effect. Herein is the crux of the challenge: while the attention may be on DarkSide ransomware, the harsh reality is that equal concern should be placed at Ryuk, or REVIL, or Babuk, or Cuba, etc. These, and other groups and their affiliates, exploit common entry vectors and, in many cases, the tools we see being used to move within an environment are the same. While this technical paper covers DarkSide in more detail, we must stress the importance of implementing best practices in securing/monitoring your network. These additional publications can guide you in doing so:
DarkSide Ransomware: What is it?
As mentioned earlier, DarkSide is a Ransomware-as-a-Service (RaaS) that offers high returns for penetration-testers that are willing to provide access to networks and distribute/execute the ransomware. DarkSide is an example of a RaaS whereby they actively invest in development of the code, affiliates, and new features. Alongside their threat to leak data, they have a separate option for recovery companies to negotiate, are willing to engage with the media, and are willing to carry out a Distributed Denial of Service (DDoS) attack against victims. Those victims who do pay a ransom receive an alert from DarkSide on companies that are on the stock exchange who are breached, in return for their payment. Potential legal issues abound, not to mention ethical concerns, but this information could certainly provide an advantage in short selling when the news breaks.
The group behind DarkSide are also particularly active. Using MVISION Insights we can identify the prevalence of targets. This map clearly illustrates that the most targeted geography is clearly the United States (at the time of writing). Further, the sectors primarily targeted are Legal Services, Wholesale, and Manufacturing, followed by the Oil, Gas and Chemical sectors.
Coverage and Protection Advice
McAfee’s market leading EPP solution covers DarkSide ransomware with an array of early prevention and detection techniques.
Customers using MVISION Insights will find a threat-profile on this ransomware family that is updated when new and relevant information becomes available.
EARLY DETECTION
MVISION EDR includes detections on many of the behaviors used in the attack including privilege escalation, malicious PowerShell and CobaltStrike beacons, and visibility of discovery commands, command and control, and other tactics along the attack chain. We have EDR telemetry indicating early detection before the detonation of the Ransomware payload.
PREVENTION
ENS TP provides coverage against known indicators in the latest signature set. Updates on new indicators are pushed through GTI.
ENS ATP provides behavioral content focusing on proactively detecting the threat while also delivering known IoCs for both online and offline detections.
ENS ATP adds two (2) additional layers of protection thanks to JTI rules that provide attack surface reduction for generic ransomware behaviors and RealProtect (static and dynamic) with ML models targeting ransomware threats.
For the latest mitigation guidance, please review:
https://kc.mcafee.com/corporate/index?page=content&id=KB93354&locale=en_US
Technical Analysis
The RaaS platform offers the affiliate the option to build either a Windows or Unix version of the ransomware. Depending on what is needed, we observe that affiliates are using different techniques to circumvent detection, by masquerading the generated Windows binaries of DarkSide. Using several packers or signing the binary with a certificate are some of the techniques used to do so.
As peers in our industry have described, we also observed campaigns where the affiliates and their hacking crew used several ways to gain initial access to their victim’s network.
- Using valid accounts, exploit vulnerabilities on servers or RDP for initial stage
- Next, establish a beachhead in the victim’s network by using tools like Cobalt-Strike (beacons), RealVNC, RDP ported over TOR, Putty, AnyDesk and TeamViewer. TeamViewer is what we also see back in the config of the ransomware sample:
The configuration of the ransomware contains several options to enable or disable system processes, but also the above part where it states which processes should not be killed.
As mentioned before, a lot of the current Windows samples in the wild are the 1.8 version of DarkSide, others are the 2.1.2.3 version. In a chat one of the actors revealed that a V3 version will be released soon.
On March 23rd, 2021, on XSS, one of the DarkSide spokespersons announced an update of DarkSide as a PowerShell version and a major upgrade of the Linux variant:
In the current samples we observe, we do see the PowerShell component that is used to delete the Volume Shadow copies, for example.
- Once a strong foothold has been established, several tools are used by the actors to gain more privileges.
Tools observed:
- Mimikatz
- Dumping LSASS
- IE/FireFox password dumper
- Powertool64
- Empire
- Bypassing UAC
- Once enough privileges are gained, it is time to map out the network and identify the most critical systems like servers, storage, and other critical assets. A selection of the below tools was observed to have been used in several cases:
- BloodHound
- ADFind
- ADRecon
- IP scan tools
- Several Windows native tools
- PowerShell scripts
Before distributing the ransomware around the network using tools like PsExec and PowerShell, data was exfiltrated to Cloud Services that would later be used on the DarkSide Leak page for extortion purposes. Zipping the data, using Rclone or WinSCP are some of the examples observed.
While a lot of good and in-depth analyses are written by our peers, one thing worth noting is that when running DarkSide, the encryption process is fast. It is one of the areas the actors brag about on the same forum and do a comparison to convince affiliates to join their program:
DarkSide, like Babuk ransomware, has a Linux version. Both target *nix systems but in particular VMWare ESXi servers and storage/NAS. Storage/NAS is critical for many companies, but how many of you are running a virtual desktop, hosted on a ESXi server?
Darkside wrote a Linux variant that supports the encryption of ESXI server versions 5.0 – 7.1 as well as NAS technology from Synology. They state that other NAS/backup technologies will be supported soon.
In the code we clearly observe this support:
Also, the configuration of the Linux version shows it is clearly looking for Virtual Disk/memory kind of files:
Although the adversary recently claimed to vote for targets, the attacks are ongoing with packed and signed samples observed as recently as today (May 12, 2021):
Conclusion
Recently the Ransomware Task Force, a partnership McAfee is proud to be a part of, released a detailed paper on how ransomware attacks are occurring and how countermeasures should be taken. As many of us have published, presented on, and released research upon, it is time to act. Please follow the links included within this blog to apply the broader advice about applying available protection and detection in your environment against such attacks.
MITRE ATT&CK Techniques Leveraged by DarkSide:
Data Encrypted for Impact – T1486
Inhibit System Recovery – T1490
Valid Accounts – T1078
PowerShell – T1059.001
Service Execution – T1569.002
Account Manipulation – T1098
Dynamic-link Library Injection – T1055.001
Account Discovery – T1087
Bypass User Access Control – T1548.002
File Permissions Modification – T1222
System Information Discovery – T1082
Process Discovery – T1057
Screen Capture – T1113
Compile After Delivery – T1027.004
Credentials in Registry – T1552.002
Obfuscated Files or Information – T1027
Shared Modules – T1129
Windows Management Instrumentation – T1047
Exploit Public-Facing Application – T1190
Phishing – T1566
External Remote Services – T1133
Multi-hop Proxy – T1090.003
Exploitation for Privilege Escalation – T1068
Application Layer Protocol – T1071
Bypass User Account Control – T1548.002
Commonly Used Port – T1043
Compile After Delivery – T1500
Credentials from Password Stores – T1555
Credentials from Web Browsers – T1555.003
Credentials in Registry – T1214
Deobfuscate/Decode Files or Information – T1140
Disable or Modify Tools – T1562.001
Domain Account – T1087.002
Domain Groups – T1069.002
Domain Trust Discovery – T1482
Exfiltration Over Alternative Protocol – T1048
Exfiltration to Cloud Storage – T1567.002
File and Directory Discovery – T1083
Gather Victim Network Information – T1590
Ingress Tool Transfer – T1105
Linux and Mac File and Directory Permissions Modification – T1222.002
Masquerading – T1036
Process Injection – T1055
Remote System Discovery – T1018
Scheduled Task/Job – T1053
Service Stop – T1489
System Network Configuration Discovery – T1016
System Services – T1569
Taint Shared Content – T1080
Unix Shell – T1059.004
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