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February 17, 2021

Compromised 2FA: Preventing Microsoft Account Takeovers

Discover how Darktrace's Microsoft 365 connector detected and investigated a 2FA-compromised Microsoft account takeover. Learn these preventative measures!
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.
Written by
Max Heinemeyer
Global Field CISO
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17
Feb 2021

What is Two-factor authentication (2FA)?

2FA is now relied upon by almost a third of businesses. It requires a user to present more than one method of identification when logging into an account. This prevents cyber-criminals from simply using password credentials to hack a system; instead, extra security layers, such as biometrics (inherence), personal information (knowledge), or a code sent to your phone or email (possession), are required to gain access to an account.

What happens when 2FA has been compromised?

Darktrace recently observed this exact scenario when a Microsoft 365 account was hijacked and the attacker temporarily changed the authentication settings so that the SMS codes were sent to their phone. The attack attempted to blend into the user activity and remain undetected. However, Darktrace was able to identify the account compromise from subtle anomalies in the user’s behavior, including suspicious logins, unusual email rule creations, and file deletions.

There has been a sharp increase in these SaaS-based attacks, which comes as no surprise as companies increasingly rely on SaaS platforms to conduct their remote business. Microsoft 365 is now used regularly across organizations for email, user management, file storage and sharing. This phenomenon has widened the attack surface and provides great opportunities for cyber-criminals. SaaS platforms are often siloed, and security teams tend to lack visibility over them and struggle to correlate events across these multiple platforms.

Darktrace Cyber AI protects the entire SaaS environment, providing full coverage over Microsoft 365 and Azure platforms. In this case, the customer was using the Microsoft 365 module. Despite the attack bypassing all other security tools, it was identified by Darktrace’s Microsoft 365 connector and investigated by Cyber AI Analyst – the world’s first AI investigation technology, which automatically triages, interprets, and reports on the full scope of security incidents.

How a Microsoft account was compromised through 2FA

An account belonging to a user on the financial team of a company with around 10,000 Microsoft 365 users was recently compromised. The initial infection most likely happened because the employee had clicked on a malicious link in a phishing email.

Figure 1: A timeline of the attack

Darktrace began detecting suspicious logins into the Microsoft 365 account from unusual locations in the US and Ghana. These logins successfully passed the multi-factor authentication (MFA) security, as the attacker had subtly manipulated the user’s details, modifying the registered phone number so the authentication text message went directly to them.

Figure 2: Darktrace’s dedicated SaaS console surfaces unusual activity across Microsoft 365

2FA can be compromised using several tactics. It may be hacked via a SIM swapping attack or through the use of a malicious OAuth application. An attacker could even resort to a phishing or social-engineering attack, and work in real time to use the one-time password at the same time as the victim enters it on the phishing page.

Following the unusual logins, Darktrace observed that the attacker had changed email rules for the compromised user’s account, as well as several shared inboxes, including one related to credit control.

During this time, the attacker was seen accessing multiple emails in the compromised user’s inbox. The attacker may have been scouring the inbox for sensitive data, or familiarizing themselves with the user’s normal activity and writing style, enabling them to craft believable phishing emails impersonating the account owner. The attacker also deleted multiple emails for that user in an attempt to cover their tracks.

While the rest of the organization’s security stack was blind to this threat, Darktrace’s Microsoft 365 connector detected the anomalous behavior and launched an automated investigation with Cyber AI Analyst. The security team then responded, before the attacker was able to fully exploit some of the critical shared mailboxes.

Had the hacker been able to continue, they would have been able to access intellectual property (IP) and sensitive financial data about the organization and its customers. This could have served as ammunition for future fraudulent payment requests, which have been known to cost organizations tens of thousands of dollars.

Cyber AI Analyst investigates 2FA threat

Trained on hundreds of expert cyber analysts, Cyber AI Analyst conducts autonomous investigations on the full range of threats – including SaaS account compromise. In this case, it stitched together the anomalous login and user behavior and generated a natural language summary of the incident, ready for review. A human analyst would have taken an average of three hours to do this. Yet Cyber AI Analyst did it in a matter of seconds, delivering a 92% time saving.

Figure 3: A demonstration of how Cyber AI Analyst reports on unusual logins and file access

Concluding thoughts

The dynamic workforce is more dispersed than ever, relying on SaaS applications and sprawling IT systems to host valuable data. In this digitally globalized world, cyber security must also be ubiquitous, providing full visibility across the digital environment.

This cyber-attack was targeted and sophisticated. The attack had used compromised credentials so no bruteforce activity was seen prior to the successful logins. Furthermore, the attacker passed the two-factor authentication, as well as covering their tracks through deleted emails and blending into legitimate user activity.

Darktrace AI, however, detected the subtle anomalies in the user’s behavior and thus identified that there was an unwanted presence in the environment. Darktrace is able to cover attacks in cloud and SaaS across the entire attack lifecycle – from an initial spear phishing email to full account takeover – even when other security methods, such as 2FA, have been compromised. In these attacks, early detection and response is key. There could have been significant financial and reputational repercussions had Darktrace not detected the attack.

Thanks to Darktrace analyst Brianna Leddy for her insights on the above threat find.

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.
Written by
Max Heinemeyer
Global Field CISO

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July 3, 2025

Top Eight Threats to SaaS Security and How to Combat Them

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The latest on the identity security landscape

Following the mass adoption of remote and hybrid working patterns, more critical data than ever resides in cloud applications – from Salesforce and Google Workspace, to Box, Dropbox, and Microsoft 365.

On average, a single organization uses 130 different Software-as-a-Service (SaaS) applications, and 45% of organizations reported experiencing a cybersecurity incident through a SaaS application in the last year.

As SaaS applications look set to remain an integral part of the digital estate, organizations are being forced to rethink how they protect their users and data in this area.

What is SaaS security?

SaaS security is the protection of cloud applications. It includes securing the apps themselves as well as the user identities that engage with them.

Below are the top eight threats that target SaaS security and user identities.

1.  Account Takeover (ATO)

Attackers gain unauthorized access to a user’s SaaS or cloud account by stealing credentials through phishing, brute-force attacks, or credential stuffing. Once inside, they can exfiltrate data, send malicious emails, or escalate privileges to maintain persistent access.

2. Privilege escalation

Cybercriminals exploit misconfigurations, weak access controls, or vulnerabilities to increase their access privileges within a SaaS or cloud environment. Gaining admin or superuser rights allows attackers to disable security settings, create new accounts, or move laterally across the organization.

3. Lateral movement

Once inside a network or SaaS platform, attackers move between accounts, applications, and cloud workloads to expand their foot- hold. Compromised OAuth tokens, session hijacking, or exploited API connections can enable adversaries to escalate access and exfiltrate sensitive data.

4. Multi-Factor Authentication (MFA) bypass and session hijacking

Threat actors bypass MFA through SIM swapping, push bombing, or exploiting session cookies. By stealing an active authentication session, they can access SaaS environments without needing the original credentials or MFA approval.

5. OAuth token abuse

Attackers exploit OAuth authentication mechanisms by stealing or abusing tokens that grant persistent access to SaaS applications. This allows them to maintain access even if the original user resets their password, making detection and mitigation difficult.

6. Insider threats

Malicious or negligent insiders misuse their legitimate access to SaaS applications or cloud platforms to leak data, alter configurations, or assist external attackers. Over-provisioned accounts and poor access control policies make it easier for insiders to exploit SaaS environments.

7. Application Programming Interface (API)-based attacks

SaaS applications rely on APIs for integration and automation, but attackers exploit insecure endpoints, excessive permissions, and unmonitored API calls to gain unauthorized access. API abuse can lead to data exfiltration, privilege escalation, and service disruption.

8. Business Email Compromise (BEC) via SaaS

Adversaries compromise SaaS-based email platforms (e.g., Microsoft 365 and Google Workspace) to send phishing emails, conduct invoice fraud, or steal sensitive communications. BEC attacks often involve financial fraud or data theft by impersonating executives or suppliers.

BEC heavily uses social engineering techniques, tailoring messages for a specific audience and context. And with the growing use of generative AI by threat actors, BEC is becoming even harder to detect. By adding ingenuity and machine speed, generative AI tools give threat actors the ability to create more personalized, targeted, and convincing attacks at scale.

Protecting against these SaaS threats

Traditionally, security leaders relied on tools that were focused on the attack, reliant on threat intelligence, and confined to a single area of the digital estate.

However, these tools have limitations, and often prove inadequate for contemporary situations, environments, and threats. For example, they may lack advanced threat detection, have limited visibility and scope, and struggle to integrate with other tools and infrastructure, especially cloud platforms.

AI-powered SaaS security stays ahead of the threat landscape

New, more effective approaches involve AI-powered defense solutions that understand the digital business, reveal subtle deviations that indicate cyber-threats, and action autonomous, targeted responses.

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Carlos Gray
Senior Product Marketing Manager, Email

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July 2, 2025

Pre-CVE Threat Detection: 10 Examples Identifying Malicious Activity Prior to Public Disclosure of a Vulnerability

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Vulnerabilities are weaknesses in a system that can be exploited by malicious actors to gain unauthorized access or to disrupt normal operations. Common Vulnerabilities and Exposures (or CVEs) are a list of publicly disclosed cybersecurity vulnerabilities that can be tracked and mitigated by the security community.

When a vulnerability is discovered, the standard practice is to report it to the vendor or the responsible organization, allowing them to develop and distribute a patch or fix before the details are made public. This is known as responsible disclosure.

With a record-breaking 40,000 CVEs reported for 2024 and a predicted higher number for 2025 by the Forum for Incident Response and Security Teams (FIRST) [1], anomaly-detection is essential for identifying these potential risks. The gap between exploitation of a zero-day and disclosure of the vulnerability can sometimes be considerable, and retroactively attempting to identify successful exploitation on your network can be challenging, particularly if taking a signature-based approach.

Detecting threats without relying on CVE disclosure

Abnormal behaviors in networks or systems, such as unusual login patterns or data transfers, can indicate attempted cyber-attacks, insider threats, or compromised systems. Since Darktrace does not rely on rules or signatures, it can detect malicious activity that is anomalous even without full context of the specific device or asset in question.

For example, during the Fortinet exploitation late last year, the Darktrace Threat Research team were investigating a different Fortinet vulnerability, namely CVE 2024-23113, for exploitation when Mandiant released a security advisory around CVE 2024-47575, which aligned closely with Darktrace’s findings.

Retrospective analysis like this is used by Darktrace’s threat researchers to better understand detections across the threat landscape and to add additional context.

Below are ten examples from the past year where Darktrace detected malicious activity days or even weeks before a vulnerability was publicly disclosed.

ten examples from the past year where Darktrace detected malicious activity days or even weeks before a vulnerability was publicly disclosed.

Trends in pre-cve exploitation

Often, the disclosure of an exploited vulnerability can be off the back of an incident response investigation related to a compromise by an advanced threat actor using a zero-day. Once the vulnerability is registered and publicly disclosed as having been exploited, it can kick off a race between the attacker and defender: attack vs patch.

Nation-state actors, highly skilled with significant resources, are known to use a range of capabilities to achieve their target, including zero-day use. Often, pre-CVE activity is “low and slow”, last for months with high operational security. After CVE disclosure, the barriers to entry lower, allowing less skilled and less resourced attackers, like some ransomware gangs, to exploit the vulnerability and cause harm. This is why two distinct types of activity are often seen: pre and post disclosure of an exploited vulnerability.

Darktrace saw this consistent story line play out during several of the Fortinet and PAN OS threat actor campaigns highlighted above last year, where nation-state actors were seen exploiting vulnerabilities first, followed by ransomware gangs impacting organizations [2].

The same applies with the recent SAP Netweaver exploitations being tied to a China based threat actor earlier this spring with subsequent ransomware incidents being observed [3].

Autonomous Response

Anomaly-based detection offers the benefit of identifying malicious activity even before a CVE is disclosed; however, security teams still need to quickly contain and isolate the activity.

For example, during the Ivanti chaining exploitation in the early part of 2025, a customer had Darktrace’s Autonomous Response capability enabled on their network. As a result, Darktrace was able to contain the compromise and shut down any ongoing suspicious connectivity by blocking internal connections and enforcing a “pattern of life” on the affected device.

This pre-CVE detection and response by Darktrace occurred 11 days before any public disclosure, demonstrating the value of an anomaly-based approach.

In some cases, customers have even reported that Darktrace stopped malicious exploitation of devices several days before a public disclosure of a vulnerability.

For example, During the ConnectWise exploitation, a customer informed the team that Darktrace had detected malicious software being installed via remote access. Upon further investigation, four servers were found to be impacted, while Autonomous Response had blocked outbound connections and enforced patterns of life on impacted devices.

Conclusion

By continuously analyzing behavioral patterns, systems can spot unusual activities and patterns from users, systems, and networks to detect anomalies that could signify a security breach.

Through ongoing monitoring and learning from these behaviors, anomaly-based security systems can detect threats that traditional signature-based solutions might miss, while also providing detailed insights into threat tactics, techniques, and procedures (TTPs). This type of behavioral intelligence supports pre-CVE detection, allows for a more adaptive security posture, and enables systems to evolve with the ever-changing threat landscape.

Credit to Nathaniel Jones (VP, Security & AI Strategy, Field CISO), Emma Fougler (Global Threat Research Operations Lead), Ryan Traill (Analyst Content Lead)

References and further reading:

  1. https://www.first.org/blog/20250607-Vulnerability-Forecast-for-2025
  2. https://cloud.google.com/blog/topics/threat-intelligence/fortimanager-zero-day-exploitation-cve-2024-47575
  3. https://thehackernews.com/2025/05/china-linked-hackers-exploit-sap-and.html

Related Darktrace blogs:

*Self-reported by customer, confirmed afterwards.

**Updated January 2024 blog now reflects current findings

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