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Dissecting the SolarWinds hack without the use of signatures

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06
Jan 2021
06
Jan 2021
This blog explains how activity related to the SolarWinds hack can be detected without the use of signatures, and why a self-learning approach is the best possible mechanism to catch this Advanced Persistent Threat.

For a high-level explanation of the SolarWinds hack, watch our video below.

The SUNBURST malware attacks against SolarWinds have heightened companies’ concerns about the risk to their digital environments. Malware installed during software updates in March 2020 has allowed advanced attackers to gain unauthorized access to files that may include customer data and intellectual property.

Darktrace does not use SolarWinds, and its operations remain unaffected by this breach. However, SolarWinds is an IT discovery tool that is used by a significant number of Darktrace customers. In what follows, we explore a set of Darktrace detections that highlight and alert security teams to the types of behaviors related to this breach.

This is not an example of a SolarWinds compromise, but examples of anomalous behaviors we can expect to see from this type of breach. These examples stress the value of self-learning Cyber AI capable of understanding the evolving normal ‘patterns of life’ within an enterprise – as opposed to a signature-based approach that looks at historical data to predict today’s threat.

As Darktrace detects device activity patterns rather than known malicious signatures, detecting use of these techniques will fall into the scope of Darktrace’s capabilities without further need for configuration. The technology automatically clusters devices into ‘peer groups’, allowing it to detect cases of an individual device behaving unusually. Using a self-learning approach is the best possible mechanism to catch an attacker who gains access into your systems using a degree of stealth so as to not trigger signature-based detection.

A number of these models may fire in combination with other models in order to make a strong detection over a time-series – and this is exactly where Darktrace’s autonomous incident triage capability, Cyber AI Analyst, plays a crucial role in investigating the alerts on behalf of security teams. Cyber AI Analyst saves critical time for security teams, and its results should be treated with a high priority during this period of vigilance.

How SolarWinds was detected with AI

We want to focus on the most sophisticated details of the hands-on intrusion that in many cases followed the initial automated attack. This post-exploitation part of the attack is much more varied and stealthy. These stages are also near-impossible to predict, as they are driven by the attacker’s intentions and goals for each individual victim at this stage – making the use of signatures, threat intelligence or static use cases virtually useless.

While the automated, initial malware execution is a critical initial step to understand, the behavior was pre-configured for the malware and included the download of further payloads and the connection to domain-generation-algorithm (DGA) based subdomains of avsvmcloud[.]com. These automated first stages of the attack have been sufficiently researched in depth by the community. This post is not aiming to add anything to these findings, but instead takes a look at the potential post-infection activities.

Malware / C2 domains

The threat-actor set the hostnames on their later-stage command and control (C2) infrastructure to match a legitimate hostname found within the victim’s environment. This allowed the adversary to blend into the environment, avoid suspicion, and evade detection. They further used C2 servers in geopolitical proximity to their victims, further circumventing static geo-based trusts lists. Darktrace is unaffected by this type of tradecraft as it does not have implicit, pre-defined trust of any geo-locations.

This would be very likely to trigger the following Darktrace Cyber AI models. The models were not specifically designed to detect SolarWinds modifications but have been in place for years – they are designed to detect the subtle but significant attacker activities occurring within an organization’s network.

  • Compromise / Agent Beacon to New Endpoint
  • Compromise / SSL Beaconing to New Endpoint
  • Compromise / HTTP Beaconing to New Endpoint*

*The implant uses SSL, but may be identified as HTTP if using a proxy.

Lateral movement using different credentials

Once the attacker gained access to the network with compromised credentials, they moved laterally using multiple different credentials. The credentials used for lateral movement were always different from those used for remote access.

This very likely would trigger the following Cyber AI models:

  • User / Multiple Uncommon New Credentials on Device
Figure 1: Example breach event log showing anomalous (new) logins from a single device, with multiple user credentials
  • User / New Admin Credentials on Client
Figure 2: Example breach event log showing anomalous admin login

Temporary file replacement and temporary task modification

The attacker used a temporary file replacement technique to remotely execute utilities: they replaced a legitimate utility with theirs, executed their payload, and then restored the legitimate original file. They similarly manipulated scheduled tasks by updating an existing legitimate task to execute their tools and then returned the scheduled task to its original configuration. They routinely removed their tools – including the removal of backdoors once legitimate remote access was achieved.

This would be very likely to trigger the following Cyber AI models:

  • Anomalous Connection / New or Uncommon Service Control
Figure 3: Example breach showing uncommon service control
  • Anomalous Connection / High Volume of New or Uncommon Service Control
Figure 4: Example breach showing 10 uncommon service controls
  • Device / AT Service Scheduled Task
Figure 5: Breach event log shows new AT service scheduled task activity
  • Device / Multiple RPC Requests for Unknown Services
Figure 6: Breach shows multiple binds to unknown RPC services
  • Device / Anomalous SMB Followed By Multiple Model Breaches
Figure 7: Breach shows unusual SMB activity, combined with slow beaconing
  • Device / Suspicious File Writes to Multiple Hidden SMB Shares
Figure 8: Breach shows device writing .bat file to temp folder on another device
  • Unusual Activity / Anomalous SMB to New or Unusual Locations
Figure 9: Breach shows new access to SAMR, combined with SMB Reads and Kerberos login failures
  • Unusual Activity / Sustained Anomalous SMB Activity
Figure 10: Breach shows significant deviation in SMB activity from device

SolarWinds breach remembered

By understanding where credentials are used and which devices talk to each other, Cyber AI has an unprecedented and dynamic understanding of business systems. This empowers it to alert security teams to enterprise changes that could indicate cyber risk in real time.

These alerts demonstrate how AI learns ‘normal’ for the unique digital environment surrounding it, and then alerts operators to deviations, including those that are directly relevant to the SUNBURST compromise. It further provides insights into how the attacker exploited those networks that did not have the appropriate visibility and detection capabilities.

On top of these alerts, Cyber AI Analyst will also be automatically correlating these detections over time to identify patterns, generating comprehensive and intuitive incident summaries and significantly reducing triage time. Reviewing Cyber AI Analyst alerts should be given high priority over the next several weeks.


INSIDE THE SOC
Darktrace cyber analysts are world-class experts in threat intelligence, threat hunting and incident response, and provide 24/7 SOC support to thousands of Darktrace customers around the globe. Inside the SOC is exclusively authored by these experts, providing analysis of cyber incidents and threat trends, based on real-world experience in the field.
AUTHOR
ABOUT ThE AUTHOR
Max Heinemeyer
Chief Product Officer

Max is a cyber security expert with over a decade of experience in the field, specializing in a wide range of areas such as Penetration Testing, Red-Teaming, SIEM and SOC consulting and hunting Advanced Persistent Threat (APT) groups. At Darktrace, Max is closely involved with Darktrace’s strategic customers & prospects. He works with the R&D team at Darktrace, shaping research into new AI innovations and their various defensive and offensive applications. Max’s insights are regularly featured in international media outlets such as the BBC, Forbes and WIRED. Max holds an MSc from the University of Duisburg-Essen and a BSc from the Cooperative State University Stuttgart in International Business Information Systems.

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Inside the SOC

Identifying the Imposter: Darktrace’s Detection of Simulated Malware vs the Real Thing

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13
Mar 2024

Distinguishing attack simulations from the real thing

In an era marked by the omnipresence of digital technologies and the relentless advancement of cyber threats, organizations face an ongoing battle to safeguard their digital environment. Although red and blue team exercises have long served as cornerstones in evaluating organizational defenses, their reliance on manual processes poses significant constraints [1]. Led by seasoned security professionals, these tests offer invaluable insights into security readiness but can be marred by their resource-intensive and infrequent testing cycles. The gaps between assessments leave organizations open to undetected vulnerabilities, compromising the true state of their security environment. In response to the ever-changing threat landscape, organizations are adopting a proactive stance towards cyber security to fortify their defenses.

At the forefront, these efforts tend to revolve around simulated attacks, a process designed to test an organization's security posture against both known and emerging threats in a safe and controlled environment [2]. These meticulously orchestrated simulations imitate the tactics, techniques, and procedures (TTPs) employed by actual adversaries and provide organizations with invaluable insights into their security resilience and vulnerabilities. By immersing themselves in simulated attack scenarios, security teams can proactively probe for vulnerabilities, adopt a more aggressive defense posture, and stay ahead of evolving cyber threats.

Distinguishing between simulated malware observations and authentic malware activities stands as a critical imperative for organizations bolstering their cyber defenses. While simulated platforms offer controlled scenarios for testing known attack patterns, Darktrace’s Self-Learning AI can detect known and unknown threats, identify zero-day threats, and previously unseen malware variants, including attack simulations. Whereas simulated platforms focus on specific known attack vectors, Darktrace DETECT™ and Darktrace RESPOND™ can identify and contain both known and unknown threats across the entire attack surface, providing unparalleled protection of the cyber estate.

Darktrace’s Coverage of Simulated Attacks

In January 2024, the Darktrace Security Operations Center (SOC) received a high volume of alerts relating to an unspecified malware strain that was affecting multiple customers across the fleet, raising concerns, and prompting the Darktrace Analyst team to swiftly investigate the multitude of incident. Initially, these activities were identified as malicious, exhibiting striking resemblance to the characteristics of Remcos, a sophisticated remote access trojan (RAT) that can be used to fully control and monitor any Windows computer from XP and onwards [3]. However, further investigation revealed that these activities were intricately linked to a simulated malware provider.

This discovery underscores a pivotal insight into Darktrace’s capabilities. To this point, leveraging advanced AI, Darktrace operates with a sophisticated framework that extends beyond conventional threat detection. By analyzing network behavior and anomalies, Darktrace not only discerns between simulated threats, such as those orchestrated by breach and attack simulation platforms and genuine malicious activities but can also autonomously respond to these threats with RESPOND. This showcases Darktrace’s advanced capabilities in effectively mitigating cyber threats.

Attack Simulation Process: Initial Access and Intrusion

Darktrace initially observed devices breaching several DETECT models relating to the hostname “new-tech-savvy[.]com”, an endpoint that was flagged as malicious by multiple open-source intelligence (OSINT) vendors [4].

In addition, multiple HTML Application (HTA) file downloads were observed from the malicious endpoint, “new-tech-savvy[.]com/5[.]hta”. HTA files are often seen as part of the UAC-0050 campaign, known for its cyber-attacks against Ukrainian targets, which tends to leverage the Remcos RAT with advanced evasion techniques [5] [6]. Such files are often critical components of a malware operation, serving as conduits for the deployment of malicious payloads onto a compromised system. Often, within the HTA file resides a VBScript which, upon execution, triggers a PowerShell script. This PowerShell script is designed to facilitate the download of a malicious payload, namely “word_update.exe”, from a remote server. Upon successful execution, “word_update.exe” is launched, invoking cmd.exe and initiating the sharing of malicious data. This process results in the execution of explorer.exe, with the malicious RemcosRAT concealed within the memory of explorer.exe. [7].

As the customers were subscribed to Darktrace’s Proactive Threat Notification (PTN) service, an Enhanced Monitoring model was breached upon detection of the malicious HTA file. Enhanced Monitoring models are high-fidelity DETECT models designed to identify activity likely to be indicative of compromise. These PTN alerts were swiftly investigated by Darktrace’s round the clock SOC team.

Following this successful detection, Darktrace RESPOND took immediate action by autonomously blocking connections to the malicious endpoint, effectively preventing additional download attempts. Similar activity may be seen in the case of a legitimate malware attack; however, in this instance, the hostname associated with the download confirmed the detected malicious activity was the result of an attack simulation.

Figure 1: The Breach Log displays the model breach, “Anomalous File/Incoming HTA File”, where a device was detected downloading the HTA file, “5.hta” from the endpoint, “new-tech-savvy[.]com”.
'
Figure 2: The Model Breach Event Log shows a device making connections to the endpoint, “new-tech-savvy[.]com”. As a result, theRESPOND model, “Antigena/Network/External Threat/Antigena File then New Outbound Block", breached and connections to this malicious endpoint were blocked.
Figure 3: The Breach Log further showcases another RESPOND model, “Antigena/Network/External Threat/Antigena Suspicious File Block", which was triggered when the device downloaded a  HTA file from the malicious endpoint, “new-tech-savvy[.]com".

In other cases, Darktrace observed SSL and HTTP connections also attributed to the same simulated malware provider, highlighting Darktrace’s capability to distinguish between legitimate and simulated malware attack activity.

Figure 4: The Model Breach “Anomalous Connection/Low and Slow Exfiltration" displays the hostname of a simulated malware provider, confirming the detected malicious activity as the result of an attack simulation.
Figure 5: The Model Breach Event Log shows the SSL connections made to an endpoint associated with the simulated malware provider.
Figure 6: Darktrace’s Advanced Search displays SSL connection logs to the endpoint of the simulated malware provider around the time the simulation activity was observed.

Upon detection of the malicious activity occurring within affected customer networks, Darktrace’s Cyber AI Analyst™ investigated and correlated the events at machine speed. Figure 8 illustrates the synopsis and additional technical information that AI Analyst generated on one customer’s environment, detailing that over 220 HTTP queries to 18 different endpoints for a single device were seen. The investigation process can also be seen in the screenshot, showcasing Darktrace’s ability to provide ‘explainable AI’ detail. AI Analyst was able to autonomously search for all HTTP connections made by the breach device and identified a single suspicious software agent making one HTTP request to the endpoint, 45.95.147[.]236.

Furthermore, the malicious endpoints, 45.95.147[.]236, previously observed in SSH attacks using brute-force or stolen credentials, and “tangible-drink.surge[.]sh”, associated with the Androxgh0st malware [8] [9] [10], were detected to have been requested by another device.

This highlights Darktrace’s ability to link and correlate seemingly separate events occurring on different devices, which could indicate a malicious attack spreading across the network.  AI Analyst was also able to identify a username associated with the simulated malware prior to the activity through Kerberos Authentication Service (AS) requests. The device in question was also tagged as a ‘Security Device’ – such tags provide human analysts with valuable context about expected device activity, and in this case, the tag corroborates with the testing activity seen. This exemplifies how Darktrace’s Cyber AI Analyst takes on the labor-intensive task of analyzing thousands of connections to hundreds of endpoints at a rapid pace, then compiling results into a single pane that provides customer security teams with the information needed to evaluate activities observed on a device.

All in all, this demonstrates how Darktrace’s Self-Learning AI is capable of offering an unparalleled level of awareness and visibility over any anomalous and potentially malicious behavior on the network, saving security teams and administrators a great deal of time.

Figure 7: Cyber AI Analyst Incident Log containing a summary of the attack simulation activity,, including relevant technical details, and the AI investigation process.

Conclusion

Simulated cyber-attacks represent the ever-present challenge of testing and validating security defenses, while the threat of legitimate compromise exemplifies the constant risk of cyber threats in today’s digital landscape. Darktrace emerges as the solution to this conflict, offering real-time detection and response capabilities that identify and mitigate simulated and authentic threats alike.

While simulations are crafted to mimic legitimate threats within predefined parameters and controlled environments, the capabilities of Darktrace DETECT transcend these limitations. Even in scenarios where intent is not malicious, Darktrace’s ability to identify anomalies and raise alerts remains unparalleled. Moreover, Darktrace’s AI Analyst and autonomous response technology, RESPOND, underscore Darktrace’s indispensable role in safeguarding organizations against emerging threats.

Credit to Priya Thapa, Cyber Analyst, Tiana Kelly, Cyber Analyst & Analyst Team Lead

Appendices

Model Breaches

Darktrace DETECT Model Breach Coverage

Anomalous File / Incoming HTA File

Anomalous Connection / Low and Slow Exfiltration

Darktrace RESPOND Model Breach Coverage

§  Antigena / Network/ External Threat/ Antigena File then New Outbound Block

Cyber AI Analyst Incidents

• Possible HTTP Command and Control

• Suspicious File Download

List of IoCs

IP Address

38.52.220[.]2 - Malicious Endpoint

46.249.58[.]40 - Malicious Endpoint

45.95.147[.]236 - Malicious Endpoint

Hostname

tangible-drink.surge[.]sh - Malicious Endpoint

new-tech-savvy[.]com - Malicious Endpoint

References

1.     https://xmcyber.com/glossary/what-are-breach-and-attack-simulations/

2.     https://www.picussecurity.com/resource/glossary/what-is-an-attack-simulation

3.     https://success.trendmicro.com/dcx/s/solution/1123281-remcos-malware-information?language=en_US&sfdcIFrameOrigin=null

4.     https://www.virustotal.com/gui/url/c145cf7010545791602e9585f447347c75e5f19a0850a24e12a89325ded88735

5.     https://www.virustotal.com/gui/url/7afd19e5696570851e6413d08b6f0c8bd42f4b5a19d1e1094e0d1eb4d2e62ce5

6.     https://thehackernews.com/2024/01/uac-0050-group-using-new-phishing.html

7.     https://www.uptycs.com/blog/remcos-rat-uac-0500-pipe-method

8.     https://www.virustotal.com/gui/ip-address/45.95.147.236/community

9.     https://www.virustotal.com/gui/domain/tangible-drink.surge.sh/community

10.  https://www.cisa.gov/news-events/cybersecurity-advisories/aa24-016a

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Priya Thapa
Cyber Analyst

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Mastering Cloud Migration: Strategies, Services, and Risks

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12
Mar 2024

What is cloud migration?

Cloud migration, in its simplest form, refers to the process of moving digital assets, such as data, applications, and IT resources, from on-premises infrastructure or legacy systems to cloud computing environments. There are various flavours of migration and utilization, but according to a survey conducted by IBM, one of the most common is the 'Hybrid' approach, with around 77% of businesses adopting a hybrid cloud approach.

There are three key components of a hybrid cloud migration model:

  1. On-Premises (On-Prem): Physical location with some amount of hardware and networking, traditionally a data centre.
  2. Public Cloud: Third-party providers like AWS, Azure, and Google, who offer multiple services such as Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS), and Software-as-a-Service (SaaS).
  3. Private Cloud: A cloud computing environment where resources are isolated for one customer.

Why does cloud migration matter for enterprises?

Cloud adoption provides many benefits to businesses, including:

  1. Scalability: Cloud environments allow enterprises to scale resources up or down based on demand, enabling them to quickly adapt to changing business requirements.
  2. Flexibility and Agility: Cloud platforms provide greater flexibility and agility, enabling enterprises to innovate and deploy new services more rapidly compared to traditional on-premises infrastructure.
  3. Cost Efficiency: Pay-as-you-go model, allowing enterprises to reduce capital expenditures on hardware and infrastructure.
  4. Enhanced Security: Cloud service providers invest heavily in security measures to protect data and infrastructure, offering advanced security features and compliance certifications.

The combination of these benefits provides significant potential for businesses to innovate and move quickly, ultimately allowing them to be flexible and adapt to changing market conditions, customer demands, and technological advancements with greater agility and efficiency.

Cloud migration strategy

There are multiple migration strategies a business can adopt, including:

  1. Rehosting (Lift-and-shift): Quickly completed but may lead to increased costs for running workloads.
  2. Refactoring (Cloud Native): Designed specifically for the cloud but requires a steep learning curve and staff training on new processes.
  3. Hybrid Cloud: Mix of on-premises and public cloud use, offering flexibility and scalability while keeping data secure on-premises. This can introduce complexities in setup and management overhead and requires ensuring security and compliance in both environments.

It is important to note that each strategy has its trade-offs and there is no single gold standard for a one size fits all cloud migration strategy. Different businesses will prioritize and leverage different benefits, for instance while some might prefer a rehosting strategy as it gets them migrated the fastest, it typically ends up also being the most costly strategy as “lift-and-shift” doesn’t take advantage of many key benefits that the cloud has to offer. Conversely, refactoring is a strategy optimized at making the most of the benefits that cloud providers have to offer, however the process of redesigning applications requires cloud expertise and based on the scale of applications that are required to be refactored this strategy might not be the quickest when it comes to moving applications from being hosted on premise to in the cloud.  

Phases of a cloud migration

At the highest level, there are four main steps in a successful migration:

  1. Discover: Identify and categorize IT assets, applications, and critical dependencies.
  2. Plan: Develop a detailed migration plan, including timelines, resource allocation, and risk management strategies.
  3. Migrate: Execute the migration plan, minimizing disruption to business operations.
  4. Optimize: Continuously optimize the cloud environment using automation, performance monitoring, and cost management tools to improve efficiency, performance, and scalability.

While it is natural to race towards the end goals of a cloud migration, most successful cloud migration strategies allocate the appropriate timelines to each phase.  

The “Discover” phase specifically is where most businesses can set themselves up for success. Having a complete understanding of assets, applications, services, and dependencies needed to migrate however is much easier said than done. Given the pace of change and how laborious of a task inventorying everything can be to manage and maintain, most mistakes at this stage will propagate and amplify through the migration journey.  

Risks and challenges of cloud migration

Though cloud migration offers a wealth of benefits, it also introduces new risks that need to be accounted for and managed effectively. Security should be considered a fundamental part of the process, not an additional measure that can be ‘bolted’ on at the end.

Let’s consider the most popular migration strategy, using a ‘Hybrid Cloud’. A recent report by the industry analyst group Forrester cited that Cloud Security Posture Management (CSPM) tools are just one facet of security, stating:

"No matter how good it is, using a CSPM solution alone will not provide you with full visibility, detection, and effective remediation capabilities for all threats. Your adversaries are also targeting operating systems, existing on-prem network infrastructure, and applications in their quest to steal valuable data".

Unpacking some of the risks here, it’s clear they fall into a range of categories, including:

  1. Security Concerns: Ensuring security across both on-premises and cloud environments, addressing potential misconfigurations and vulnerabilities.
  2. Contextual Understanding: Effective security requires a deep understanding of the organization's business processes and the context in which data and applications operate.
  3. Threat Detection and Response: Identifying and responding to threats in real-time requires advanced capabilities such as AI and anomaly detection.
  4. Platform Approach: Deploying integrated security solutions that provide end-to-end visibility, centralized management, and automated responses across hybrid infrastructure.

Since the cloud doesn’t operate in a vacuum, businesses will always have a myriad of 3rd party applications, users, endpoints, external services, and partners connecting and interacting with their cloud environments. From this perspective, being able to correlate and understand behaviors and activity both within the cloud and its surroundings becomes imperative.

It then follows that context from a business wide perspective is necessary. This has two distinct implications, the first is application or workload specific context (i.e. where do the assets, services, and functions alerted on reside within the cloud application) and the second is business wide context. Given the volume of alerts that security practitioners need to manage, findings that lack the appropriate context to fully understand and resolve the issue create additional strain on teams that are already managing a difficult challenge.  

Conclusion

With that in mind, Darktrace’s approach to security, with its existing and new advances in Cloud Detection and Response capabilities, anomaly detection across SaaS applications, and native ability to leverage many AI techniques to understand the business context within your dynamic cloud environment and on-premises infrastructure. It provides you with the integrated building blocks to provide the ‘360’ degree view required to detect and respond to threats before, during, and long after your enterprise migrates to the cloud.

References

IBM Transformation Index: State of Cloud https://www.ibm.com/blog/hybrid-cloud-use-cases/

https://www.forrester.com/report/the-top-trends-shaping-cloud-security-posture-management-cspm-in-2024/RES180379  

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About the author
Adam Stevens
Analyst Technical Director
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