Top 5 Security Threats in Microsoft 365

WME Article - Top 5 Security Threats in Microsoft 365

Microsoft 365 is a powerful suite of cloud-based productivity and collaboration tools that can help businesses of all sizes save time and money. However, like any cloud-based solution, Microsoft 365 is not immune to security threats. In this blog post, we will discuss five of the most common security threats to Microsoft 365. We will also provide tips on how to protect yourself from these threats.

Let’s dive in.

The most significant security risks within Microsoft 365

1. Vulnerabilities in Multi-Factor Authentication (MFA)

Multi-factor authentication (MFA) is a vital security measure that safeguards user accounts by requiring multiple forms of identification.

Microsoft recognizes the significance of MFA and has integrated it into all editions of Microsoft 365. By combining factors such as passwords, biometrics, or hardware tokens, MFA aims to ensure that only authorized individuals can access sensitive information and resources.

The Threat Actor Conundrum: Circumventing MFA Controls

Despite the implementation of MFA across Microsoft 365, threat actors have exhibited a disconcerting ability to circumvent these security controls. These malicious individuals employ various tactics to compromise user accounts and gain unauthorized access to valuable data. By exploiting vulnerabilities in user behavior, social engineering techniques, or technical weaknesses in the authentication process, threat actors can successfully bypass MFA.

For example, in 2020, a group of threat actors used malware to steal the MFA tokens of users at a large technology company. The attackers were then able to use these tokens to gain unauthorized access to the company’s systems.

Legacy Authentication Protocols and MFA Limitations

One significant avenue for MFA circumvention lies in the utilization of legacy authentication protocols, such as IMAP/POP3.

These protocols were developed at a time when the concept of MFA was not prevalent. Consequently, they lack built-in support for MFA, creating a vulnerability that threat actors eagerly exploit.

By utilizing these outdated protocols, attackers can bypass MFA, gaining access to user accounts without encountering any additional authentication measures.

The Importance of Restricting Legacy Authentication

To address the vulnerabilities posed by legacy authentication protocols, it is imperative to restrict their usage. Organizations and individuals should proactively disable or limit the use of IMAP/POP3 protocols to minimize the risk of MFA circumvention.

By adopting modern authentication protocols that are MFA-compatible, such as OAuth, the security posture of Microsoft 365 can be significantly enhanced.

But, even OAuth is not completely dependable…

MFA Circumvention through OAuth Authorization

One way that hackers can bypass MFA using OAuth is by creating a fake application that looks like a legitimate one. Once the user has granted access to the fake application, the hacker can then use the application to access the user’s account without using MFA.

Another way that hackers can bypass MFA using OAuth is by exploiting a vulnerability in the OAuth protocol. In 2019, a vulnerability was discovered in the OAuth protocol that allowed hackers to bypass MFA. This vulnerability was patched, but it is possible that other vulnerabilities could be discovered in the future.

Manipulating Registered Phone Numbers through Social Engineering

Attackers can use social engineering to trick victims into changing their registered phone numbers. This can be done by sending phishing emails or making phone calls. Once the attacker has changed the phone number, they will be able to receive the authentication text messages and gain unauthorized access to the account.

Regardless of the approach employed by an attacker, it is vital to possess the capability to identify instances where multi-factor authentication (MFA) has been deactivated on a Microsoft 365 account.

So, one thing is clear: navigating the intricacies of MFA circumvention requires expert guidance. Only a trusted managed security services provider can offer the assurance of comprehensive protection against evolving threats. 

2. Unveiling Data Exfiltration: Understanding the Risks and Implications

Data exfiltration is the unauthorized transfer of data from a computer or network. It is a serious security threat that can have a significant impact on an organization.

Data exfiltration can be used to steal sensitive data, such as customer information, intellectual property, or financial data. It can also be used to disrupt operations or launch other attacks.

Hackers Use Power Automate for Data Exfiltration

Recently, it was discovered that attackers can use Power Automate, a Microsoft application, to exfiltrate emails and data. Power Automate is a tool that allows users to automate tasks across different Microsoft applications. This can be useful for automating repetitive tasks, but it can also be used by attackers to automate data exfiltration.

They can use Power Automate to create workflows that automatically extract data from Microsoft applications, such as emails from Outlook and files from SharePoint and OneDrive. Once the data is extracted, it can be sent to an attacker-controlled server.

This is a serious security threat because it allows attackers to exfiltrate data without having to manually access the data themselves. This makes it more difficult for organizations to detect and prevent data exfiltration attacks.

The Devastating Impact of Data Exfiltration

Data exfiltration is the final step in a cyber-attack, where the attacker steals sensitive data from a victim’s computer or network. This data can then be used for a variety of malicious purposes, such as identity theft, fraud, or espionage.

Data exfiltration can have a devastating impact on a company. If sensitive data, such as customer information, intellectual property, or financial data, is stolen, it can cost the company millions of dollars in lost revenue, fines, and legal fees. It can also damage the company’s reputation and make it difficult to attract new customers and partners.

How to Prevent Data Exfiltration?

To prevent data exfiltration, it is important to be able to detect behaviors that may indicate an attempt to steal data. Some common behaviors that may indicate data exfiltration include:

  • File sharing with personal email addresses
  • Mass downloading of files
  • Exceeding send limits

You May Need an MSP To Handle Data Exfiltration Threats

To safeguard against data exfiltration, organizations need comprehensive solutions that encompass behavioral analysis, data loss prevention, network segmentation, and user training. By investing in a managed security provider, businesses can proactively mitigate the risks of data exfiltration, stay ahead of evolving threats, and maintain the trust of their customers and stakeholders.

3. Privilege Escalation: The Ultimate Culprit

What is Privilege Escalation?

Privilege escalation is a type of attack that allows an attacker to gain more privileges on a system (mostly, at the level of domain administrator) than they are authorized to have.

This can be done by exploiting a vulnerability in the system or by using a malicious program. Once an attacker has escalated their privileges, they can then do things like steal data, install malware, or disrupt operations.

Different ways to exploit privilege escalation vulnerabilities.

Some of the most common methods include:

1. Exploiting Software Vulnerabilities: Attackers may discover and exploit vulnerabilities in the system’s software, such as operating systems, applications, or plugins, to gain elevated privileges. These vulnerabilities could be in the form of buffer overflows, code injection, or weak authentication mechanisms.

2. Misconfiguration or Weak Access Controls: Improperly configured access controls, weak passwords, or misconfigured user roles and permissions can provide an opportunity for privilege escalation. Attackers may exploit these weaknesses to gain higher-level access within the system.

3. Exploiting Default Accounts or Backdoors: Some systems come with default accounts or backdoor access mechanisms that are often overlooked or forgotten. Attackers can leverage these accounts or mechanisms to escalate their privileges.

4. Social Engineering: Privilege escalation can also occur through social engineering techniques, where attackers manipulate individuals with higher privileges to perform actions on their behalf or provide sensitive information that enables elevated access.

Living off the land (LotL): The Most Subtle Way

Living off the land (LotL) is a privilege escalation technique where an attacker uses legitimate tools and utilities that are already present on the target system to gain elevated privileges. This can be done by exploiting vulnerabilities in these tools or by using them in unintended ways.

Why are LotL attacks difficult to detect?

LotL attacks are difficult to detect because they use legitimate tools that are not typically blocked by security solutions.

That said, LotL attacks can be very stealthy, as they often do not leave any traces on the system.

It’s important to be able detect suspicious activity associated with privilege escalation, such as Attempts to access system files or folders that should not be accessed by users with the current privileges or attempts to run programs or commands with elevated privileges, etc. 

What can be the security consequences of privilege escalation?

The impact of privilege escalation can be severe, as it allows attackers to perform actions that are typically restricted to higher privileged accounts. This can include:

  • Accessing sensitive data,
  • Modifying configurations,
  • Installing malware,
  • Creating new user accounts,
  • Or taking control of the entire system.

Here is a real-world example of a LotL attack:

In 2017, the WannaCry ransomware attack infected over 200,000 computers in 150 countries. The attack used a vulnerability in the Windows Server Message Block (SMB) protocol to gain access to systems. Once they had access, the attackers used the PowerShell command-line tool to execute malicious code that encrypted the victim’s files.

In this example, the attackers used a legitimate tool (PowerShell) to gain elevated privileges and execute malicious code. This is an example of a LotL attack.

Elevation of Privilege (EoP) is the most common security vulnerability in Microsoft tools

According to the BeyondTrust 2023 Microsoft Vulnerabilities Report, the most popular type of Microsoft vulnerability in 2022-2023 was the Elevation of Privilege (EoP).

EoP vulnerabilities allow attackers to gain unauthorized access to a system or network, which can then be used to steal data, install malware, or disrupt operations.

The report found that there were 1,292 reported Microsoft vulnerabilities in 2022, an all-time high since the report began 10 years ago. Of these vulnerabilities, 32% were EoP vulnerabilities. This is the third year in a row that EoP vulnerabilities have been the most popular type of Microsoft vulnerability.

The report concludes by stating that Microsoft is doing a good job of identifying and fixing vulnerabilities, but that organizations need to be vigilant in applying security updates to protect themselves from attack.

How to prevent privilege escalation?

To prevent privilege escalation, it is essential to implement security best practices, such as:

  • Regularly applying security patches and updates to software and systems.
  • Implementing strong access controls and user permissions based on the principle of least privilege.
  • Conducting regular security assessments and vulnerability scans to identify and address potential weaknesses.
  • Enforcing strong password policies and using multi-factor authentication.
  • Monitoring and analyzing system logs for suspicious activities or unauthorized privilege changes.
  • Providing security awareness training to employees to mitigate the risk of social engineering attacks.

By following these measures, organizations can reduce the likelihood of privilege escalation and enhance the overall security of their systems and networks. However, this may not be an easy task for your in-house teams.

4. The Ongoing Battle Against Phishing Attacks

Phishing, a deceptive technique in which malicious actors send fraudulent emails under the guise of reputable organizations to extract sensitive information, has emerged as the primary attack vector for ransomware, a form of malicious software that holds data hostage.

Notably, Microsoft, despite being a significantly secure software brand, has become the most commonly impersonated entity, as revealed by recent data.

Microsoft 365’s in-built capability to prevent Phishing is not enough.

To counter phishing attempts, Microsoft 365 offers an email protection feature. This feature plays a crucial role in identifying and neutralizing phishing campaigns. However, it is important to note that this protection mechanism has its limitations.

While it diligently detects and addresses known phishing threats, it does not actively scan every aspect of email content. Moreover, the Safe Attachments feature within Microsoft 365 relies on sandboxing to identify malware, rather than employing more advanced and sophisticated detection methods.

Sandboxing, while a valuable security technique, has certain limitations that make it not necessarily the best or most comprehensive solution in all scenarios.

How is Sandboxing an outdated security technique?

Here are a few reasons:

  • Evolving Malware Techniques: Cybercriminals are constantly developing new and sophisticated methods to evade detection. Sandboxing primarily relies on analyzing the behavior of a program in an isolated environment. However, advanced malware can detect the presence of a sandbox and alter its behavior to avoid triggering any malicious activity, thus bypassing detection.
  • Zero-Day Exploits: Zero-day exploits refer to vulnerabilities that are unknown to software developers and security vendors. Sandboxing alone may not effectively protect against such exploits since it primarily focuses on detecting known patterns of malicious behavior. Without prior knowledge of the vulnerability, the sandbox may not be able to identify and block the zero-day exploit.
  • Limited Contextual Understanding: Sandboxing often lacks the ability to fully understand the context in which a program is being executed. It primarily focuses on observing the program’s behavior within a controlled environment. However, this may result in false positives or false negatives, as certain behaviors may appear benign in isolation but could be malicious in a real-world scenario.
  • Resource Intensive: Sandboxing can be computationally intensive, requiring significant resources to analyze and monitor the behavior of programs in a controlled environment. This can impact system performance and may not be feasible in resource-constrained environments or on a large scale.
  • Targeted Attacks: Sophisticated targeted attacks specifically designed to evade traditional security measures may also bypass sandboxing techniques. Attackers may employ techniques such as delayed execution or encryption to evade detection within the sandbox, allowing the malware to activate and carry out malicious activities once it has left the isolated environment.

So, while Microsoft 365’s email protection feature provides a valuable defense against phishing attacks, it is essential for users to remain vigilant and exercise caution when interacting with emails, links, and attachments.

Being proactive in recognizing potential phishing attempts can enhance the overall security posture and safeguard against potential breaches or compromises.

5. Understanding the Risks of Malicious Macros

A malicious macro is a type of malware that is embedded in a Microsoft Office document. Macros are a set of instructions that can be used to automate tasks in Microsoft Office applications. Malicious macros are designed to damage or steal data from a computer. They can be spread through email attachments, file-sharing websites, and other methods.

What can a malicious macro do?

When a malicious macro is opened, it can do a variety of things, including:

  • Delete files
  • Steal data
  • Install other malware
  • Crash the computer

Let’s consider an example of a malicious macro

  • A user receives an email from a sender they do not recognize. The email contains an attachment called “invoice.docx.”
  • The user opens the attachment, which contains a malicious macro.
  • The macro then runs and steals the user’s personal information, such as their name, address, and credit card number.

This is just one example of how malicious macros can be used to steal data. There are other ways as well that malicious actors can embed macros in documents.

Another Scenario:

One way is to send phishing emails that contain malicious attachments.

When a user opens the attachment, the macro will run and infect the user’s computer. Another way that malicious actors can embed macros is to upload malicious documents to file-sharing websites. When a user downloads the document, the macro will run and infect the user’s computer.

Microsoft’s efforts to counter malicious macros

To help users stay safe from malicious macros, Microsoft recently announced that they will automatically block Visual Basic for Applications (VBA) macros by default in their Office software. This means that users will no longer be able to simply click one button to enable macros. Instead, they will need to manually unblock macros by ticking an option on the properties of a file.

This change is a positive step towards improving the security of Microsoft Office users. By making it more difficult to enable macros, Microsoft is making it less likely that users will inadvertently open malicious files. This will help to protect users from malware and other security threats.

Empowering Your Defense: Why Relying Solely on Microsoft 365’s Built-In Security Isn’t Enough

Microsoft 365 is a powerful suite of productivity and collaboration tools that can help businesses of all sizes to be more efficient and effective. However, it is important to remember that Microsoft 365 is not a silver bullet when it comes to security. While Microsoft 365 includes a number of built-in security features, these features are not always enough to protect businesses from sophisticated cyberattacks.

Let’s explore the limitations of Microsoft 365’s built-in security and shed light on why it is imperative to augment it with supplemental security measures.

Why Microsoft 365’s Built-In Security Isn’t Enough?

There are a number of reasons why relying solely on Microsoft 365’s built-in security is not enough.

  1. First, Microsoft 365 is a constantly evolving platform, and new security threats are emerging all the time. Microsoft 365’s built-in security features may not be able to keep up with the latest threats.
  • Microsoft 365 is a cloud-based platform, and cloud-based platforms are often more vulnerable to attack than on-premises platforms. This is because cloud-based platforms are accessible from anywhere in the world, and they are often shared by multiple organizations.
  • Human error is a major factor in cyberattacks. Even the most secure organizations are vulnerable to human error, such as clicking on a malicious link or opening a malicious attachment.

For these reasons, it is important for businesses to supplement Microsoft 365’s built-in security with some Managed security services like those by WME.

Even Microsoft Defender, Despite being a reliable product that continually improves over time, alone is insufficient to provide comprehensive protection against cyberattacks targeting Microsoft 365.

How Microsoft Defender falls short of delivering top security?

Defender’s effectiveness in detecting malware falls behind that of numerous third-party competitors, the user interface is cumbersome, and it often fails to shield against emerging threats like zero-day vulnerabilities.

Also, by employing Living off the land techniques, a malicious actor can easily go undetected by endpoint detection and response (EDR) systems and Microsoft’s built-in security features.

This is because such attackers usually avoid using any known malicious tools or techniques, making it challenging for security systems to identify their activities. Even in cases where EDR does raise an alert for suspicious behavior, administrators may easily overlook or dismiss the alert as it may appear to be normal activity without the necessary contextual information.

So, some of the additional security measures that businesses can take include:

  • Using a security information and event management (SIEM) system to monitor for suspicious activity.
  • Using a web filtering solution to block malicious websites.
  • Using a data loss prevention (DLP) solution to prevent sensitive data from being exfiltrated.
  • Educating employees about cybersecurity best practices.

How WME Protects Your Microsoft 365 Environment

WME offers the industry’s top threat detection and security assessments for Microsoft 365 environment — with a focus on quick remediation and empowering your in-house teams to handle security vulnerabilities popping up in the future on their own.  

We can guide you on how you can capitalize on the additional security options mentioned above so that you don’t have to pay hefty amounts of money on different security tasks every now and then.

Contact us today to get started:



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