Darktrace recently detected a simulation of a state-of-the-art attack at an international airport, identifying ICS reconnaissance, lateral movement, vulnerability scanning and protocol fuzzing – a technique in which the attacker sends nonsensical commands over an ICS communication channel in order to confuse the target device, causing it to fail or reboot.
Darktrace’s Industrial Immune System detected every stage of the sophisticated attack, using AI-powered anomaly detection to identify ICS attack vectors without a list of known exploits, company assets, or firmware versions. The attacker leveraged tools at every stage of the ICS kill chain, including ICS-specific attack techniques.
Any unusual attempts to read or reprogram single coils, objects, or other data blocks were detected by Cyber AI, and Darktrace’s Cyber AI Analyst also automatically identified the activity and created summary reports detailing the key actions taken.
The attack spanned multiple days and targeted the Building Management System (BMS) and the Baggage Reclaim network, with attackers utilizing two common ICS protocols (BacNet and S7Comm) and leveraging legitimate tools (such as ICS reprogramming commands and connections through SMB service pipes) to evade traditional, signature-based security tools.
Attack details
Figure 1: Timeline of the attack
In the first stage of the attack, a new device was introduced to the network, using ARP spoofing to evade detection from traditional security tools. At 11.40am, the attacker scanned a target device and attempted to bruteforce open services. Once the target device had been hijacked, the attacker then sought to establish an external connection to the Internet. External connections should not be possible in ICS networks, but attackers often seek to bypass firewalls and network segregation rules in order to create a command and control (C2) channel.
Figure 2: Darktrace Threat Tray 15 minutes after the pentest commenced. High level model breaches have already alerted the analyst team to the attack device.
The hijacked device then began performing ICS reconnaissance using Discover and Read commands. Darktrace identified new objects and data blocks being targeted as part of this reconnaissance, and detected ICS devices targeted with unusual BacNet and Siemens S7Comm protocol commands.
Figure 3: Model alerts associated with ICS reconnaissance over BacNet. Machine learning at the ICS command level detected new and unusual BacNet objects being targeted by the attacker.
The attacker enumerated through multiple ICS devices in order to perform lateral movement throughout the ICS system. Once they had learned device settings and configurations, they used ICS Reprogram and Write commands to reconfigure machines. The attacker attempted to use known vulnerabilities to exploit the target devices, such as the use of SMB, SMBv1, HTTP, RDP, and ICS protocol fuzzing.
Figure 4: Visualization of the device enumeration performed by the attacker against multiple ICS controllers. The attacker used ICS Discover commands as part of the initial reconnaissance.
The attacker took deliberate actions to evade the airport’s cyber security stack, including making connections using ICS protocols commonly used on the network to devices which commonly use those protocols. While legacy security tools failed to pick up on this activity, Darktrace’s deep packet inspection was able to identify unusual commands used by the attacker within those ‘normal’ connections.
The attacker used ARP spoofing to slow any investigation using asset management-based security tools – including two other solutions being trialed by the airport at the time of the attack. They also used multiple devices throughout the intrusion to throw defense teams off the scent.
Darktrace’s AI technology also launched an automated investigation into the incident. The Cyber AI Analyst identified all of the attack devices and produced summary reports for each, showcasing its ability to not only save crucial time for security teams, but bridge the skills gap between IT teams and ICS engineers.
Figure 5: The Cyber AI Analyst threat tray at the end of day 1. Both devices used by the attacker have been identified.
The Cyber AI Analyst immediately began investigating after the first model breach, and continued to stitch together disparate events across the network to produce a natural language summary of the incident, including recommendations for action.
Figure 6: AIA incident summary at the end of day 2, detailing the use of SMB exploits as part of the attack chain against one of the ICS devices.
Potential ramifications
Had the attack been allowed to continue, the attackers – potentially activist groups, terrorist organizations, and organized criminals – could have caused significant operational disruption to the airport. For example, the BMS is likely to manage temperature settings, the sprinkler system, fire alarms and fire exits, lighting, and doors in and out of secure access areas. Meddling with any one of these could cause severe disruption at an airport, with significant financial and reputational effects. Similarly, access to baggage reclaim networks could be used by criminals seeking to smuggle illegal goods or steal valuable cargo.
This simulation showcases the possibilities for an advanced cyber-criminal looking to compromise integrated IT and OT networks. The majority of leading ICS ‘security’ vendors are signature-based, and fail to pick up on novel techniques and utilization of common protocols to pursue malicious ends – this is why ICS attacks have continued to hit the headlines this year.
The incident showcases the extent of Cyber AI’s detections in a real-world ICS environment, and the level of detail Darktrace can provide following an attack. As Industrial Control Systems become increasingly integrated with the wider IT network, the importance of securing these critical systems is paramount. Darktrace provides a unified security umbrella with visibility and detection across the entire digital environment.
Thanks to Darktrace analyst Oakley Cox for his insights on the above investigation.
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
David Masson
VP, Enterprise Security
David Masson is Darktrace’s Director of Enterprise Security, and has over two decades of experience working in fast moving security and intelligence environments in the UK, Canada and worldwide. With skills developed in the civilian, military and diplomatic worlds, he has been influential in the efficient and effective resolution of various unique national security issues. David is an operational solutions expert and has a solid reputation across the UK and Canada for delivery tailored to customer needs. At Darktrace, David advises strategic customers across North America and is also a regular contributor to major international and national media outlets in Canada where he is based. He holds a master’s degree from Edinburgh University.
Darktrace has been named as Microsoft UK Partner of the Year for 2024! The Microsoft Partner Awards recognize winners for their commitment to customers, impact of solutions, and exemplary use of Microsoft technologies.
Whilst the award was granted based on our innovations combining Darktrace/Email and Microsoft Defender for Office 365, our shared values go beyond technology. Darktrace stood out for the integration of our products to deliver exceptional security value to customers, as well as our investment in partnerships, marketplace and go to market. Microsoft was also impressed with our strong commitment to diversity and inclusion and our broader contribution to both the UK economy and the UK tech sector.
Microsoft Defender for Office 365 + Darktrace/Email leave attackers nowhere to hide
The email threat landscape is constantly evolving. Attacks are becoming more sophisticated, more targeted and increasing in multi-stage payload attacks. Across the Darktrace customer base in 2023 alone, we have seen a 135% increase in ‘novel social engineering attacks’, corresponding with the rise of ChatGPT, 45% of phishing emails were identified as spear phishing attempts and a 59% increase in multi-stage payload attacks.
Legacy defenses were built to address a high volume of unsophisticated attacks, but generative AI has shifted the threats towards lower quantity yet very sophisticated, high impact targeted attacks. Microsoft Defender for Office 365’s rapid innovation has outpaced the Secure Email Gateway’s rule and signature based historical data approach. Customers no longer need email gateways which duplicate workflows and add expense native to their Defender for O365 solution.
Point email solutions overlap with Microsoft in 3 key areas: detection approach, workflows, capabilities
Detection - Microsoft receives trillions threat signals daily, giving customers the broadest scope of the attack landscape. Darktrace combined with Microsoft unites business and attack centric approaches
Workflows – any Microsoft configurations are reflected automatically in Darktrace/Email. Users can keep daily workflow in Microsoft, while a traditional SEG requires duplicated workflows
Capabilities – Microsoft handles foundational elements like archiving/encryption/signature matching while Darktrace handles advanced threat security
Darktrace/Email is built to elevate, not duplicate, Microsoft email security – removing the burden of operating legacy point solutions and blocking 25% more threats. Robust account takeover protections to stop the 38% of sophisticated threats other tools miss. Customers can seamlessly correlate activity and insights across Microsoft email, DMARC and Teams to stop threats on average 13 days earlier.
Azure Marketplace
Microsoft Azure customers can access Darktrace in the Azure Marketplace to take advantage of the scalability, reliability, and agility of Azure to drive rapid IT operations and security integrations across the enterprise. Customers can leverage their Microsoft Azure Consumption Commitments (MACC), making procurement simple. As UK Partner of the Year winner, customers know they have a trusted partner with Darktrace and a proven solution to work seamlessly with Azure.
Following up on our Conversation: Detecting & Containing a LinkedIn Phishing Attack with Darktrace
25
Jun 2024
Note: Real organization, domain and user names have been modified and replaced with fictitious names to maintain anonymity.
Social media cyber-attacks
Social media is a known breeding ground for cyber criminals to easily connect with a near limitless number of people and leverage the wealth of personal information shared on these platforms to defraud the general public. Analysis suggests even the most tech savvy ‘digital natives’ are vulnerable to impersonation scams over social media, as criminals weaponize brands and trends, using the promise of greater returns to induce sensitive information sharing or fraudulent payments [1].
LinkedIn phishing
As the usage of a particular social media platform increases, cyber criminals will find ways to exploit the increasing user base, and this trend has been observed with the rise in LinkedIn scams in recent years [2]. LinkedIn is the dominant professional networking site, with a forecasted 84.1million users by 2027 [3]. This platform is data-driven, so users are encouraged to share information publicly, including personal life updates, to boost visibility and increase job prospects [4] [5]. While this helps legitimate recruiters to gain a good understanding of the user, an attacker could also leverage the same personal content to increase the sophistication and success of their social engineering attempts.
Darktrace detection of LinkedIn phishing
Darktrace detected a Software-as-a-Service (SaaS) compromise affecting a construction company, where the attack vector originated from LinkedIn (outside the monitoring of corporate security tools), but then pivoted to corporate email where a credential harvesting payload was delivered, providing the attacker with credentials to access a corporate file storage platform.
Because LinkedIn accounts are typically linked to an individual’s personal email and are most commonly accessed via the mobile application [6] on personal devices that are not monitored by security teams, it can represent an effective initial access point for attackers looking to establish an initial relationship with their target. Moreover, user behaviors to ignore unsolicited emails from new or unknown contacts are less frequently carried over to platforms like LinkedIn, where interactions with ‘weak ties’ as opposed to ‘strong ties’ are a better predictor of job mobility [7]. Had this attack been allowed to continue, the threat actor could have leveraged access to further information from the compromised business cloud account to compromise other high value accounts, exfiltrate sensitive data, or defraud the organization.
LinkedIn phishing attack details
Reconnaissance
The initial reconnaissance and social engineering occurred on LinkedIn and was thus outside the purview of corporate security tools, Darktrace included.
However, the email domain “hausconstruction[.]com” used by the attacker in subsequent communications appears to be a spoofed domain impersonating a legitimate construction company “haus[.]com”, suggesting the attacker may have also impersonated an employee of this construction company on LinkedIn. In addition to spoofing the domain, the attacker seemingly went further to register “hausconstruction.com” on a commercial web hosting platform. This is a technique used frequently not just to increase apparent legitimacy, but also to bypass traditional security tools since newly registered domains will have no prior threat intelligence, making them more likely to evade signature and rules-based detections [8]. In this instance, open-source intelligence (OSINT) sources report that the domain was created several months earlier, suggesting this may have been part of a targeted attack on construction companies.
Initial Intrusion
It was likely that during the correspondence over LinkedIn, the target user was solicited into following up over email regarding a prospective construction project, using their corporate email account. In a probable attempt to establish a precedent of bi-directional correspondence so that subsequent malicious emails would not be flagged by traditional security tools, the attacker did not initially include suspicious links, attachments or use solicitous or inducive language within their initial emails.
Figure 1: Example of bi-directional email correspondence between the target and the attacker impersonating a legitimate employee of the construction company haus.com.
Figure 2: Cyber AI Analyst investigation into one of the initial emails the target received from the attacker.
To accomplish the next stage of their attack, the attacker shared a link, hidden behind the inducing text “VIEW ALL FILES”, to a malicious file using the Hightail cloud storage service. This is also a common method employed by attackers to evade detection, as this method of file sharing does not involve attachments that can be scanned by traditional security tools, and legitimate cloud storage services are less likely to be blocked.
OSINT analysis on the malicious link link shows the file hosted on Hightail was a HTML file with the associated message “Following up on our LinkedIn conversation”. Further analysis suggests the file contained obfuscated Javascript that, once opened, would automatically redirect the user to a malicious domain impersonating a legitimate Microsoft login page for credential harvesting purposes.
Figure 3: The malicious HTML file containing obfuscated Javascript, where the highlighted string references the malicious credential harvesting domain.
Figure 4: Screenshot of fraudulent Microsoft Sign In page hosted on the malicious credential harvesting domain.
Although there was prior email correspondence with the attacker, this email was not automatically deemed safe by Darktrace and was further analyzed for unusual properties and unusual communications for the recipient and the recipient’s peer group.
Darktrace determined that:
It was unusual for this file storage solution to be referenced in communications to the user and the wider network
Textual properties of the email body suggested a high level of inducement from the sender, with a high level of focus on the phishing link.
The full link contained suspicious properties suggesting it is high risk.
Figure 5: Darktrace’s analysis of the phishing email, presenting key information about the unusual characteristics of this email, information on highlighted content, and an overview of actions that were initially applied.
Based on these anomalies, Darktrace initially moved the phishing email to the junk folder and locked the link, preventing the user from directly accessing the malicious file hosted on Hightail. However, the customer’s security team released the email, likely upon end-user request, allowing the target user to access the file and ultimately enter their credentials into that credential harvesting domain.
Figure 6: Darktrace alerts triggered by the malicious phishing email and the corresponding Autonomous Response actions.
Lateral Movement
Correspondence between the attacker and target continued for two days after the credential harvesting payload was delivered. Five days later, Darktrace detected an unusual login using multi-factor authentication (MFA) from a rare external IP and ASN that coincided with Darktrace/Email logs showing access to the credential harvesting link.
This attempt to bypass MFA, known as an Office365 Shell WCSS attack, was likely achieved by inducing the target to enter their credentials and legitimate MFA token into the fake Microsoft login page. This was then relayed to Microsoft by the attacker and used to obtain a legitimate session. The attacker then reused the legitimate token to log into Exchange Online from a different IP and registered the compromised device for MFA.
Figure 7: Screenshot within Darktrace/Email of the phishing email that was released by the security team, showing the recipient clicked the link to file storage where the malicious payload was stored.
Figure 8: Event Log showing a malicious login and MFA bypass at 17:57:16, shortly after the link was clicked. Highlighted in green is activity from the legitimate user prior to the malicious login, using Edge. Highlighted in orange and red is the malicious activity using Chrome.
The IP addresses used by the attacker appear to be part of anonymization infrastructure, but are not associated with any known indicators of compromise (IoCs) that signature-based detections would identify [9] [10].
In addition to logins being observed within half an hour of each other from multiple geographically impossible locations (San Francisco and Phoenix), the unexpected usage of Chrome browser, compared to Edge browser previously used, provided Darktrace with further evidence that this activity was unlikely to originate from the legitimate user. Although the user was a salesperson who frequently travelled for their role, Darktrace’s Self-Learning AI understood that the multiple logins from these locations was highly unusual at the user and group level, and coupled with the subsequent unexpected account modification, was a likely indicator of account compromise.
Accomplish mission
Although the email had been manually released by the security team, allowing the attack to propagate, additional layers of defense were triggered as Darktrace's Autonomous Response initiated “Disable User” actions upon detection of the multiple unusual logins and the unauthorized registration of security information.
However, the customer had configured Autonomous Response to require human confirmation, therefore no actions were taken until the security team manually approved them over two hours later. In that time, access to mail items and other SharePoint files from the unusual IP address was detected, suggesting a potential loss of confidentiality to business data.
Figure 9: Advanced Search query showing several FilePreviewed and MailItemsAccessed events from either the IPs used by the attacker, or using the software Chrome. Note some of the activity originated from Microsoft IPs which may be whitelisted by traditional security tools.
However, it appears that the attacker was able to maintain access to the compromised account, as login and mail access events from 199.231.85[.]153 continued to be observed until the afternoon of the next day.
Conclusion
This incident demonstrates the necessity of AI to security teams, with Darktrace’s ActiveAI Security Platform detecting a sophisticated phishing attack where human judgement fell short and initiated a real-time response when security teams could not physically respond as fast.
Security teams are very familiar with social engineering and impersonation attempts, but these attacks remain highly prevalent due to the widespread adoption of technologies that enable these techniques to be deployed with great sophistication and ease. In particular, the popularity of information-rich platforms like LinkedIn that are geared towards connecting with unknown people make it an attractive initial access point for malicious attackers.
In the second half of 2023 alone, over 200 thousand fake profiles were reported by members on LinkedIn [11]. Fake profiles can be highly sophisticated, use professional images, contain compelling descriptions, reference legitimate company listings and present believable credentials.
It is unrealistic to expect end users to defend themselves against such sophisticated impersonation attempts. Moreover, it is extremely difficult for human defenders to recognize every fraudulent interaction amidst a sea of fake profiles. Instead, defenders should leverage AI, which can conduct autonomous investigations without human biases and limitations. AI-driven security can ensure successful detection of fraudulent or malicious activity by learning what real users and devices look like and identifying deviations from their learned behaviors that may indicate an emerging threat.
Appendices
Darktrace Model Detections
DETECT/ Apps
SaaS / Compromise / SaaS Anomaly Following Anomalous Login
SaaS / Compromise / Unusual Login and Account Update
