How to Detect and Prevent Phishing Attacks in Microsoft Office 365
Data breaches in Microsoft 365 can cause severe damage to any business using this SaaS suite. Since most cyberattacks begin with a phishing email, reliable Microsoft Office 365 phishing protection is critical to safeguard business data.
This post lists the different types of Microsoft 365 phishing emails and explains how to detect them. Read on to discover the strategies to enhance your organization’s security against cyber breaches.
What is Phishing in Microsoft Office 365?
Before proceeding with the attack types and countermeasures, let’s define phishing. Understanding the nature of this particular cyber threat helps IT experts effectively protect business infrastructures and data against it.
Definition of phishing
Security specialists refer to phishing as a cyberattack tactic that utilizes the elements of social engineering via email messaging to deceive a user and conduct an IT breach. The purpose of the deception may vary from sharing the password to downloading malicious software attached to an email. The majority of ransomware attacks occur after a phishing-induced cyber breach.
Why Microsoft Office 365 is a common phishing target
Hackers target Microsoft 365 infrastructures because of the value of data and the potential profits that can result from stealing that data. They usually compose O365 phishing emails that look familiar to the victim. This can be an assistance request from a colleague, some corporate news, or a service subscription renewal. To make malicious emails look legitimate, the sender addresses are usually spoofed to seem correct at first glance.
Another challenge is that social engineering in general, and Microsoft 365 phishing in particular, is evolving to become more sophisticated and effective. Hackers can adjust their emails to the current local and global events, use personalized approaches and improve the credibility of the messages with other new tricks. Artificial intelligence is probably the most threatening tool that boosts the dangers here. AI can increase the frequency and impact of cyberattacks at every stage, from initial reconnaissance and infiltration to AI-powered ransomware.
Types of Microsoft Office 365 Phishing Attacks
Understanding the different types of phishing attacks can help you effectively protect your organization’s infrastructure and data against this threat.
Bulk phishing
This method involves sending tens of thousands of emails to as many recipients as the hacker has in the database. Bulk phishing is not about selective approaches; these emails usually target the broadest possible audience since they rely on numbers, not contents. Bulk phishing is frequent to receive yet relatively easy to detect. Built-in Microsoft Office 365 scam and spam filters can efficiently reveal and highlight bulk phishing emails.
Spear phishing
Contrary to bulk phishing, spear phishing relies on thorough social engineering to craft deeply personalized messages. Specific users are targeted here, which makes this phishing type more effective than any other cyberattack.
Before crafting a spear phishing email, hackers can conduct preliminary reconnaissance to gather information about the target organization, its partners, chief executives and employees. AI-assisted tools make research simpler and faster, so we can expect spear phishing attempts to become more frequent.
Attackers use the collected data to compose a seemingly legitimate message containing names, locations, phone numbers or events familiar to the target. To sum up, spear phishing is more time-consuming for an attacker than bulk phishing but more effective.
Whaling
At its core, whaling is a sub-type of spear phishing that primarily targets high-ranking executives, investors and business owners. Hackers customize whaling emails to look like media requests, financial messages or business contacts to attract and manipulate top-level individuals. For instance, whaling messages mimic payment invoices, customer requests or partnership contracts.
Unaware victims are desired targets due to the knowledge and data they hold and the system access level their corporate accounts typically have. Compromising an executive account can give hackers significant access privileges to sensitive information. They can then use that breach to organize a large-scale attack.
CEO fraud
Another type of Office 365 phishing email tactic is CEO fraud. In these phishing emails, an attacker can act as a CEO sharing something important with employees. For instance, a message can look like a vital policy update or urgent financial transfer request. However, the purpose remains: to deceive recipients and make them share data, click a malicious link or download an infected attachment.
To better understand this type of phishing, imagine a person expecting a career promotion and receiving an email about that. Attackers would most probably spoof the email address, copy the corporate email layout and, with the current state of AI, even mimic the communication style of that organization’s CEO. The team member reads the message from the fake executive and then, following the instructions, clicks the link and deploys ransomware in the corporate environment.
Filter evasion
Microsoft implements a strong Office 365 phishing filter that does not guarantee absolute detection of malicious messages. Attackers craft phishing emails that can evade software filters to get into the user’s mailbox as legitimate messages.
This phishing type can include:
- Embedding malicious code into attached images.
- Mixing links from reputable and known websites with phishing links.
- Adding lots of “clean” content to hide the malicious code.
- Applying URL shortening tools.
These tactics are pretty primitive and might not even avoid detection. However, by sending thousands of phishing emails, even one percent of messages passing through the filters can cause multiple data breaches.
PhishPoint
PhishPoint stands out when speaking of Microsoft Office 365 phishing. The hacker first inserts a malicious link into a SharePoint file in a Microsoft 365 trial. Then, the user receives an invitation to access and collaborate on some files within SharePoint.
The user clicks the link, which redirects them to a fake OneDrive file access request with a malicious URL leading to another spoofed page. The page is usually a copy of the Microsoft 365 login screen. The user then enters login credentials that are sent to the hacker’s database instead of granting access to a Microsoft 365 account.
How to Detect Phishing Attacks in Office 365
Now that you know the main types of Microsoft 365 phishing attacks, let’s proceed with their detection methods. You can identify malicious messages in your Office 365 mailbox more effectively by checking particular pieces of email content.
Phishing email signs
The typical signs that you can find in an average Microsoft Office 365 phishing email example are:
- Punctuation and grammar mistakes: “you is”, “hallo”, “can to”.
- Spelling mistakes in the organization’s name: “SqaceX”, “Micnosoft”, “Arnazon”.
- Incorrect email addresses: “support@mirosoft.com”, “press@slarbucks.com”, “johndoe@support.fasebook.com”.
- Creating a sense of urgency: “Your account will be deleted”, “Security breach”, “URGENT notice”.
- Intrusive call-to-action language – “follow the link ASAP”, “download the attachment to ensure account security”, “contact us immediately via this form”.
Artificial intelligence tools have significantly increased the threat level of Microsoft 365 phishing emails. With AI, attackers can generate a more significant number of messages in short periods while maintaining an acceptable content quality. AI-generated emails may look legitimate, but attentively checking sender addresses and links can prevent a breach.
Effective Strategies for Preventing Phishing in Office 365
The success of a Microsoft Office 365 phishing campaign is usually based on the combination of two factors:
- Insufficient Microsoft 365 phishing protection inside an organization.
- Employees who are unaware of the threat or careless enough to ignore basic online security principles.
Consider applying the following recommendations to enhance the effectiveness of O365 phishing protection in your IT environment.
Set multi-factor authentication (MFA)
Microsoft supports multi-factor authentication for its accounts. MFA adds a layer of security to Microsoft 365 sign-in procedures. With MFA enabled, the user must type a one-time verification code received by SMS or generated in a third-party authenticator application.
Setting multi-factor authentication enhances M365 security since the username and password combination won’t be enough for hackers to access an account. Microsoft recommends using an authenticator app rather than SMS verification due to security and speed benefits.
Configure Office 365 anti-phishing policies
In Exchange Online, you can set anti-phishing policies to enhance phishing protection. Correctly configuring these policies enables early detection and blocking of malicious emails. The system can analyze data like an email sender’s domain, added URLs, and potential impersonation cases.
Use email authentication standards (SPF, DKIM, DMARC)
Email authentication standards can ensure that both the sender and the email are legitimate. These standards are open and publicly available, but it’s up to the organization to implement them. The primary email authentication standards are:
- Sender Policy Framework (SPF) – checks if the sender is on the whitelist of the domain whitelist.
- DomainKeys Identified Mail (DKIM) – checks the encryption of the email and its content using the Public key infrastructure (PKI).
- Domain-based Message Authentication, Reporting and Conformance (DMARC) – checks the sender’s domain authentication using SPF and/or DKIM. DMNARC is not a standalone authentication standard.
Email authentication standards typically require some effort and time to set them up. However, they can notably reduce the number of Microsoft 365 phishing emails in the organization’s mailboxes.
Regularly update and patch software
As phishing threats keep evolving, your security for Windows, Exchange Online, Windows Defender and Office apps must remain up-to-date. This can also include third-party security solutions and apps that your organization uses to enable collaboration and support production. Regular updates help you stay protected against the latest threats and patch the recently revealed vulnerabilities.
Educate employees
Regardless of the attack type, the user is the primary target of Microsoft 365 phishing emails. A single wrong click from an employee can negate the effectiveness of the most advanced (and expensive) protection systems. Schedule infosecurity training sessions to ensure that users in your organization know enough about phishing tactics and can distinguish between legitimate and fake emails.
Additionally, it is recommended that you do not limit cybersecurity education to IT departments. Chief executives, HRs, marketing and sales specialists, accountants and anyone inside an organization can be targets of an attack. Every team member who has access to the internal IT environment must know about a threat and how to detect a Microsoft Office 365 phishing email.
Conduct drills
In addition to education, regular training can help keep employees cautious and monitor the effectiveness of your phishing protection measures. Moreover, you can easily launch a Microsoft 365 phishing test with the built-in attack simulation training. This simulation is available with Microsoft 365 E5 or Microsoft Defender for Office 365 Plan 2.
After configuring the simulation, the tool launches a test phishing email to the chosen users. You can then see how each user reacts to the attack and assign them additional training and educational content if necessary.
Backup and Protect Office 365 Data with NAKIVO
With the evolution of phishing techniques, human error leading to a security breach and data loss is a matter of when not if. When your protection is compromised and the original data is lost or corrupted, an up-to-date backup can save time, effort and money. A specialized all-in-one solution like NAKIVO Backup & Replication enables you to implement effective Microsoft 365 backup and recovery.
With NAKIVO Backup & Replication, you can run fast incremental backups of your Microsoft 365 data in Exchange Online, Microsoft Teams, SharePoint Online and OneDrive for Business. The solution supports multiple backup repositories, including local Windows and Linux folders, cloud platforms (Amazon S3, Wasabi, Azure Blob, Amazon EC2 and other S3-compatible storages), SMB/NFS file shares and deduplication appliances. You can enable source-side encryption and immutability to protect backup data from third-party access and accidental or malicious deletion. Immutable backups are immune to alteration by ransomware within the set period. In case prevention measures fail, you can restore data after a ransomware attack without paying the ransom.
You can use the advanced search functionality to find and restore the necessary data objects in Microsoft 365 backups. Near-instant recovery helps you meet regulatory compliance requirements and fulfill e-discovery requests. Backup scheduling and automation, customizable retention policies, enterprise-grade scalability and advanced multi-tenancy can cut administration expenses. NAKIVO Backup & Replication is available by subscription, licensed per user and includes 24/7 support.
Conclusion
Microsoft Office 365 phishing attacks can cause a security breach, leading to data theft or loss for any business using the suite. To enhance your organization’s Microsoft 365 phishing protection, you can set MFA, configure anti-phishing policies, apply email authentication standards and update your software. Educating employees and conducting regular cybersecurity training sessions can increase threat awareness and phishing prevention. Using data protection solutions such as NAKIVO Backup & Replication with automated data backup is the most reliable way to mitigate the outcomes of data loss incidents that usually follow security breaches.
