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September 6, 2023

The Rise of the Lumma Info-Stealer | Malware-as-a-Service

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06
Sep 2023
The emergence of Lumma Stealer, an information stealer that has recently been observed across the Darktrace fleet. Learn more about this new threat!

What are Malware-as-a-Service information stealers?

The Malware-as-a-Service (MaaS) model continues provide would-be threat actors with an inexpensive and relatively straightforward way to carry out sophisticated cyber attacks and achieve their nefarious goals. One common type of MaaS are information stealers that specialize in gathering and exfiltrating sensitive data, such as login credentials and bank details, from affected devices, potentially resulting in significant financial losses for organizations and individuals alike.

What is Lumma Information Stealer?

One such information stealer, dubbed “Lumma”, has been advertised and sold on numerous dark web forums since 2022. Lumma stealer primarily targets cryptocurrency wallets, browser extensions and two-factor authentication (2FA), before ultimately stealing sensitive information from compromised machines. The number of sightings of this malware being distributed on dark web forums is on the rise [1], and thus far, more than a dozen command-and-control (C2) servers have been observed in the wild.

Between January and April 2023, Darktrace observed and investigated multiple instances of Lumma stealer activity across the customer base. Thanks to its anomaly-based approach to threat detection, Darktrace is able to successfully identify and provide visibility over activity associated with such info-stealers, from C2 activity through to the eventual exfiltration of sensitive data.

Lumma Stealer Background

Lumma stealer, previously known as LummaC2, is a subscription-based information stealer that has been observed in the wild since 2022. It is believed to have been developed by the threat actor “Shamel”, under the the alias “Lumma”. The info-stealer has been advertised on dark web forums and also a channel on the Telegram messenger server, which boasts over a thousand subscribers as of May 2023 [2], and is also available on Lumma’s official seller page for as little as USD 250 (Figure 1).

LummaC2’s official seller website
Figure 1: LummaC2’s official seller website [3].

Research on the Russian Market selling stolen credentials has shown that Lumma stealer has been an emerging since early 2023, and joins the list of info stealers that have been on the rise, including Vidar and Racoon [1].

Similar to other info-stealers, Lumma is able to obtain system and installed program data from compromised devices, alongside sensitive information such as cookies, usernames and passwords, credit card numbers, connection history, and cryptocurrency wallet data.

Between January and April 2023, Darktrace has observed Lumma malware activity across multiple customer deployments mostly in the EMEA region, but also in the US. This included data exfiltration to external endpoints related to the Lumma malware. It is likely that this activity resulted from the download of trojanized software files or users falling victim to malicious emails containing Lumma payloads.

Lumma Attack Details and Darktrace Coverage

Typically, Lumma has been distributed disguised as cracked or fake popular software like VLC or ChatGPT. Recently though, threat actors have also delivered the malware through emails containing payloads in the form of attachments or links impersonating well-known companies. For example, in February 2023, a streamer in South Korea was targeted with a spear-phishing email in which the sender impersonated the video game company Bandai Namco [4].

Lumma is known to target Windows operating systems from Windows 7 to 11 and at least 10 different browsers including Google Chrome, Microsoft Edge, and Mozilla Firefox [5]. It has also been observed targeting crypto wallets like Binance and Ethereum, as well as crypto wallet and 2FA browser extensions like Metamask and Authenticator respectively [6]. Data from applications such as AnyDesk or KeePass can also be exfiltrated by the malware [7].

An infection with Lumma can lead to the user's information being abused for fraud, for example, using stolen credentials to hijack bank accounts, which in turn could result in significant financial losses.

Once the targeted data is obtained, it is exfiltrated to a C2 server, as Darktrace has observed on multiple customer environments affected with Lumma stealer. Darktrace identified multiple infected devices exfiltrating data via HTTP POST requests to known Lumma C2 servers. During these connections, Darktrace commonly observed the URI “/c2sock” and the user agent “TeslaBrowser/5.5”.

In one instance, Darktrace detected a device using the “TeslaBrowser/5.5” user agent, which it recognized as a new user agent for this device, whilst making a HTTP post request to an unusual IP address, 82.117.255[.]127 (Figure 3). Darktrace’s Self-Learning AI understood that this represented a deviation from expected behavior for this device and brought it to the attention of the customer’s security team.

Device Event Log on the Darktrace Threat Visualizer showing activity from a device infected with Lumma stealer and the models it breached.
Figure 2: Device Event Log on the Darktrace Threat Visualizer showing activity from a device infected with Lumma stealer and the models it breached.

Further investigation revealed that accessing the IP address using a web browser and changing the the URI to “/login”, would take a user to a Russian Lumma control panel access page (Figure 4)

 One of Lumma stealer’s C2 servers accessed via a web browser in a secured environment.
Figure 3: One of Lumma stealer’s C2 servers accessed via a web browser in a secured environment.

A deep dive into the packet captures (PCAP) of the HTTP POST requests taken from one device also confirmed that browser data, including Google Chrome history files, system information in the form of a System.txt file, and other program data such as AnyDesk configuration files were being exfiltrated from the customer’s network(Figures 5 and 6).

HTTP objects observed during Lumma Stealer POSTing of data to another one of its  C2 servers.
Figure 4: HTTP objects observed during Lumma Stealer POSTing of data to another one of its  C2 servers.
PCAP of HTTP stream showing the different types of data being exfiltrated.
Figure 5: PCAP of HTTP stream showing the different types of data being exfiltrated.

Additionally, on one particular device, Darktrace observed malicious external connections related to other malware strains, like Laplas Clipper, Raccoon Stealer, Vidar, RedLine info-stealers and trojans, around the same time as the Lumma C2 connections. These info-stealers are commonly marketed as MaaS and can be bought and used for a relatively inexpensive price by even the most inexperienced threat actors. It is also likely that the developers of these info-stealers have been making efforts to integrate their strains into the activities of traffer teams [8], organized cybercrime groups who specialize in credential theft with the use of info-stealers.

Conclusion

Mirroring the general emergence and rise of information stealers across the cyber threat landscape, Lumma stealer continues to represent a significant concern to orgaizations and individuals alike.

Moreover, as yet another example of MaaS, Lumma is readily available for threat actors to launch their attacks, regardless of their level of expertise, meaning the number of incidents is only likely to rise. As such, it is essential for organizations to have security measures in place that are able to recognize unusual behavior that may be indicative of an info-stealer compromise, while not relying on a static list of indicators of compromise (IoCs).

Darktrace's anomaly-based detection enabled it to uncover the presence of Lumma across multiple customer environments across different regions and industries. From the detection of unusual connections to C2 infrastructure to the ultimate exfiltration of customer data, Darktrace provided affected customers full visibility over Lumma infections, allowing them to identify compromised devices and take action to prevent further data loss and reduce the risk of incurring significant financial losses.

Insights from Darktrace’s First 6: Half-year threat report for 2024

First 6: half year threat report darktrace screenshot

Darktrace’s First 6: Half-Year Threat Report 2024 highlights the latest attack trends and key threats observed by the Darktrace Threat Research team in the first six months of 2024.

  • Focuses on anomaly detection and behavioral analysis to identify threats
  • Maps mitigated cases to known, publicly attributed threats for deeper context
  • Offers guidance on improving security posture to defend against persistent threats

Appendices

Credit to: Emily Megan Lim, Cyber Security Analyst, Signe Zaharka, Senior Cyber Security Analyst

Darktrace DETECT Models

·      Anomalous Connection / New User Agent to IP Without Hostname  

·      Device / New User Agent and New IP

·      Device / New User Agent

·      Anomalous Connection / Posting HTTP to IP Without Hostname

Cyber AI Analyst Incidents

·      Possible HTTP Command and Control

·      Possible HTTP Command and Control to Multiple Endpoints

List of IoCs

IoC - Type - Description + Confidence

144.76.173[.]247

IP address

Lumma C2 Infrastructure

45.9.74[.]78

IP address

Lumma C2 Infrastructure

77.73.134[.]68

IP address

Lumma C2 Infrastructure

82.117.255[.]127

IP address

Lumma C2 Infrastructure

82.117.255[.]80

IP address

Lumma C2 Infrastructure

82.118.23[.]50

IP address

Lumma C2 Infrastructure

/c2sock

URI

Lumma C2 POST Request

TeslaBrowser/5.5

User agent

Lumma C2 POST Request

MITRE ATT&CK Mapping

Tactic: Command and Control -

Technique: T1071.001 – Web Protocols

References

[1] https://www.kelacyber.com/wp-content/uploads/2023/05/KELA_Research_Infostealers_2023_full-report.pdf

[2] https://www.bleepingcomputer.com/news/security/the-new-info-stealing-malware-operations-to-watch-out-for/

[3] https://blog.cyble.com/2023/01/06/lummac2-stealer-a-potent-threat-to-crypto-users/

[4] https://medium.com/s2wblog/lumma-stealer-targets-youtubers-via-spear-phishing-email-ade740d486f7

[5] https://socradar.io/malware-analysis-lummac2-stealer/

[6] https://outpost24.com/blog/everything-you-need-to-know-lummac2-stealer

[7] https://asec.ahnlab.com/en/50594/

[8] https://blog.sekoia.io/bluefox-information-stealer-traffer-maas/

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.
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Emily Megan Lim
Cyber Analyst
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November 28, 2024

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Cloud

Cloud security: addressing common CISO challenges with advanced solutions

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Cloud adoption is a cornerstone of modern business with its unmatched potential for scalability, cost efficiency, flexibility, and net-zero targets around sustainability. However, as organizations migrate more workloads, applications, and sensitive data to the cloud it introduces more complex challenges for CISO’s. Let’s dive into the most pressing issues keeping them up at night—and how Darktrace / CLOUD provides a solution for each.

1. Misconfigurations: The Silent Saboteur

Misconfigurations remain the leading cause of cloud-based data breaches. In 2023 alone over 80%  of data breaches involved data stored in the cloud.1  Think open storage buckets or overly permissive permissions; seemingly minor errors that are easily missed and can snowball into major disasters. The fallout of breaches can be costly—both financially and reputationally.

How Darktrace / CLOUD Helps:

Darktrace / CLOUD continuously monitors your cloud asset configurations, learning your environment and using these insights to flag potential misconfigurations. New scans are triggered when changes take place, then grouped and prioritised intelligently, giving you an evolving and prioritised view of vulnerabilities, best practice and mitigation strategies.

2. Hybrid Environments: The Migration Maze

Many organizations are migrating to the cloud, but hybrid setups (where workloads span both on-premises and cloud environments) create unique challenges and visibility gaps which significantly increase complexity. More traditional and most cloud native security tooling struggles to provide adequate monitoring for these setups.

How Darktrace / CLOUD Helps:

Provides the ability to monitor runtime activity for both on-premises and cloud workloads within the same user interface. By leveraging the right AI solution across this diverse data set, we understand the behaviour of your on-premises workloads and how they interact with cloud systems, spotting unusual connectivity or data flow activity during and after the migration process.

This unified visibility enables proactive detection of anomalies, ensures seamless monitoring across hybrid environments, and provides actionable insights to mitigate risks during and after the migration process.

3. Securing Productivity Suites: The Last Mile

Cloud productivity suites like Microsoft 365 (M365) are essential for modern businesses and are often the first step for an organization on a journey to Infrastructure as a Service (IaaS) or Platform as a Service (PaaS) use cases. They also represent a prime target for attackers. Consider a scenario where an attacker gains access to an M365 account, and proceeds to; access sensitive emails, downloading files from SharePoint, and impersonating the user to send phishing emails to internal employees and external partners. Without a system to detect these behaviours, the attack may go unnoticed until significant damage is done.

How Darktrace helps:

Darktrace’s Active AI platform integrates with M365 and establishes an understanding of normal business activity, enabling the detection of abnormalities across its suite including Email, SharePoint and Teams. By identifying subtle deviations in behaviour, such as:

   •    Unusual file accesses

   •    Anomalous login attempts from unexpected locations or devices.

   •    Suspicious email forwarding rules created by compromised accounts.

Darktrace’s Autonomous Response can act precisely to block malicious actions, by disabling compromised accounts and containing threats before they escalate. Precise actions also ensure that critical business operations are maintained even when a response is triggered.  

4. Agent Fatigue: The Visibility Struggle

To secure cloud environments, visibility is critical. If you don’t know what’s there, how can you secure it? Many solutions require agents to be deployed on every server, workload, and endpoint. But managing and deploying agents across sprawling hybrid environments can be both complex and time-consuming when following change controls, and especially as cloud resources scale dynamically.

How Darktrace / CLOUD Helps:

Darktrace reduces or eliminates the need for widespread agent deployment. Its agentless by default, integrating directly with cloud environments and providing instant visibility without the operational headache. Darktrace ensures coverage with minimal friction. By intelligently graphing the relationships between assets and logically grouping your deployed Cloud resources, you are equipped with real-time visibility to quickly understand and protect your environment.

So why Darktrace / CLOUD?

Darktrace’s Self-Learning AI redefines cloud security by adapting to your unique environment, detecting threats as they emerge, and responding in real-time. From spotting misconfigurations to protecting productivity suites and securing hybrid environments. Darktrace / CLOUD simplifies cloud security challenges without adding operational burdens.

From Chaos to Clarity

Cloud security doesn’t have to be a game of endless whack-a-mole. With Darktrace / CLOUD, CISOs can achieve the visibility, control, and proactive protection they need to navigate today’s complex cloud ecosystems confidently.

[1] https://hbr.org/2024/02/why-data-breaches-spiked-in-2023

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About the author
Adam Stevens
Director of Product, Cloud Security

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November 27, 2024

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Inside the SOC

Behind the veil: Darktrace's detection of VPN exploitation in SaaS environments

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Introduction

In today’s digital landscape, Software-as-a-Service (SaaS) platforms have become indispensable for businesses, offering unparalleled flexibly, scalability, and accessibly across locations. However, this convenience comes with a significant caveat - an expanded attack surface that cyber criminals are increasingly exploiting. In 2023, 96.7% of organizations reported security incidents involving at least one SaaS application [1].

Virtual private networks (VPNs) play a crucial role in SaaS security, acting as gateways for secure remote access and safeguarding sensitive data and systems when properly configured. However, vulnerabilities in VPNs can create openings for attacks to exploit, allowing them to infiltrate SaaS environments, compromise data, and disrupt business operations. Notably, in early 2024, the Darktrace Threat Research team investigated the exploitation of zero-day vulnerabilities in Ivanti Connect Secure VPNs, which would allow threat actors to gain access to sensitive systems and execute remote code.

More recently, in August, Darktrace identified a SaaS compromise where a threat actor logged into a customer’s VPN from an unusual IP address, following an initial email compromise. The attacker then used a separate VPN to create a new email rule designed to obfuscate the phishing campaign they would later launch.

Attack Overview

The initial attack vector in this case appeared to be through the customer’s email environment. A trusted external contact received a malicious email from another mutual contact who had been compromised and forwarded it to several of the organization’s employees, believing it to be legitimate. Attackers often send malicious emails from compromised accounts to their past contacts, leveraging the trust associated with familiar email addresses. In this case, that trust caused an external victim to unknowingly propagate the attack further. Unfortunately, an internal user then interacted with a malicious payload included in the reply section of the forwarded email.

Later the same day, Darktrace / IDENTITY detected unusual login attempts from the IP 5.62.57[.]7, which had never been accessed by other SaaS users before. There were two failed attempts prior to the successful logins, with the error messages “Authentication failed due to flow token expired” and “This occurred due to 'Keep me signed in' interrupt when the user was signing in.” These failed attempts indicate that the threat actor may have been attempting to gain unauthorized access using stolen credentials or exploiting session management vulnerabilities. Furthermore, there was no attempt to use multi-factor authentication (MFA) during the successful login, suggesting that the threat actor had compromised the account’s credentials.

Following this, Darktrace detected the now compromised account creating a new email rule named “.” – a telltale sign of a malicious actor attempting to hide behind an ambiguous or generic rule name.

The email rule itself was designed to archive incoming emails and mark them as read, effectively hiding them from the user’s immediate view. By moving emails to the “Archive” folder, which is not frequently checked by end users, the attacker can conceal malicious communications and avoid detection. The settings also prevent any automatic deletion of the rules or forced overrides, indicating a cautious approach to maintaining control over the mailbox without raising suspicion. This technique allows the attacker to manipulate email visibility while maintaining a façade of normality in the compromised account.

Email Rule:

  • AlwaysDeleteOutlookRulesBlob: False
  • Force: False
  • MoveToFolder: Archive
  • Name: .
  • MarkAsRead: True
  • StopProcessingRules: True

Darktrace further identified that this email rule had been created from another IP address, 95.142.124[.]42, this time located in Canada. Open-source intelligence (OSINT) sources indicated this endpoint may have been malicious [2].

Given that this new email rule was created just three minutes after the initial login from a different IP in a different country, Darktrace recognized a geographic inconsistency. By analyzing the timing and rarity of the involved IP addresses, Darktrace identified the likelihood of malicious activity rather than legitimate user behavior, prompting further investigation.

Figure 1: The compromised SaaS account making anomalous login attempts from an unusual IP address in the US, followed by the creation of a new email rule from another VPN IP in Canada.

Just one minute later, Darktrace observed the attacker sending a large number of phishing emails to both internal and external recipients.

Figure 2: The compromised SaaS user account sending a high volume of outbound emails to new recipients or containing suspicious content.

Darktrace / EMAIL detected a significant spike in inbound emails for the compromised account, likely indicating replies to phishing emails.

Figure 3: The figure demonstrates the spike in inbound emails detected for the compromised account, including phishing-related replies.

Furthermore, Darktrace identified that these phishing emails contained a malicious DocSend link. While docsend[.]com is generally recognized as a legitimate file-sharing service belonging to Dropbox, it can be vulnerable to exploitation for hosting malicious content. In this instance, the DocSend domain in question, ‘hxxps://docsend[.]com/view/h9t85su8njxtugmq’, was flagged as malicious by various OSINT vendors [3][4].

Figure 4: Phishing emails detected containing a malicious DocSend link.

In this case, Darktrace Autonomous Response was not in active mode in the customer’s environment, which allowed the compromise to escalate until their security team intervened based on Darktrace’s alerts. Had Autonomous Response been enabled during the incident, it could have quickly mitigated the threat by disabling users and inbox rules, as suggested by Darktrace as actions that could be manually applied, exhibiting unusual behavior within the customer’s SaaS environment.

Figure 5: Suggested Autonomous Response actions for this incident that required human confirmation.

Despite this, Darktrace’s Managed Threat Detection service promptly alerted the Security Operations Center (SOC) team about the compromise, allowing them to conduct a thorough investigation and inform the customer before any further damage could take place.

Conclusion

This incident highlights the role of Darktrace in enhancing cyber security through its advanced AI capabilities. By detecting the initial phishing email and tracking the threat actor's actions across the SaaS environment, Darktrace effectively identified the threat and brought it to the attention of the customer’s security team.

Darktrace’s proactive monitoring was crucial in recognizing the unusual behavior of the compromised account. Darktrace / IDENTITY detected unauthorized access attempts from rare IP addresses, revealing the attacker’s use of a VPN to hide their location.

Correlating these anomalies allowed Darktrace to prompt immediate investigation, showcasing its ability to identify malicious activities that traditional security tools might miss. By leveraging AI-driven insights, organizations can strengthen their defense posture and prevent further exploitation of compromised accounts.

Credit to Priya Thapa (Cyber Analyst), Ben Atkins (Senior Model Developer) and Ryan Traill (Analyst Content Lead)

Appendices

Real-time Detection Models

  • SaaS / Compromise / Unusual Login and New Email Rule
  • SaaS / Compromise / High Priority New Email Rule
  • SaaS / Compromise / New Email Rule and Unusual Email Activity
  • SaaS / Compromise / Unusual Login and Outbound Email Spam
  • SaaS / Compliance / Anomalous New Email Rule
  • SaaS / Compromise / Suspicious Login and Suspicious Outbound Email(s)
  • SaaS / Email Nexus / Possible Outbound Email Spam

Autonomous Response Models

  • Antigena / SaaS / Antigena Email Rule Block
  • Antigena / SaaS / Antigena Enhanced Monitoring from SaaS User Block
  • Antigena / SaaS / Antigena Suspicious SaaS Activity Block

MITRE ATT&CK Mapping

Technique Name Tactic ID Sub-Technique of

  • Cloud Accounts. DEFENSE EVASION, PERSISTENCE, PRIVILEGE ESCALATION, INITIAL ACCESS T1078.004 T1078
  • Compromise Accounts RESOURCE DEVELOPMENT T1586
  • Email Accounts RESOURCE DEVELOPMENT T1586.002 T1586
  • Internal Spearphishing LATERAL MOVEMENT T1534 -
  • Outlook Rules PERSISTENCE T1137.005 T1137
  • Phishing INITIAL ACCESS T1566 -

Indicators of Compromise (IoCs)

IoC – Type – Description

5.62.57[.]7 – Unusual Login Source

95.142.124[.]42– IP – Unusual Source for Email Rule

hxxps://docsend[.]com/view/h9t85su8njxtugmq - Domain - Phishing Link

References

[1] https://wing.security/wp-content/uploads/2024/02/2024-State-of-SaaS-Report-Wing-Security.pdf

[2] https://www.virustotal.com/gui/ip-address/95.142.124.42

[3] https://urlscan.io/result/0caf3eee-9275-4cda-a28f-6d3c6c3c1039/

[4] https://www.virustotal.com/gui/url/8631f8004ee000b3f74461e5060e6972759c8d38ea8c359d85da9014101daddb

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About the author
Priya Thapa
Cyber Analyst
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