For years, security teams focused heavily on detecting malware. A suspicious executable appears on an endpoint. Antivirus detects malicious activity. An analyst investigates processes, network connections, and indicators of compromise to determine the impact. While malware remains an important threat, many modern attacks no longer require malicious software at all.

Instead of deploying malware, attackers increasingly abuse legitimate cloud services, stolen credentials, OAuth permissions, SaaS applications, and trusted third-party integrations to gain access and persist within an environment. This shift has fundamentally changed the attack surface organizations must defend.

Today, applications such as Microsoft 365, Google Workspace, Salesforce, Slack, GitHub, Dropbox, and numerous other Software-as-a-Service (SaaS) platforms contain some of the most valuable organizational data. They also provide attackers with opportunities to operate using legitimate identities and trusted services, making detection significantly more challenging.

For defenders, the question is no longer simply:

“Is malware present?”

It increasingly becomes:

“Is this activity legitimate?”

Understanding how attackers abuse SaaS platforms is now a critical requirement for modern security operations teams.

A SaaS attack occurs when an adversary abuses a cloud-hosted software platform to gain unauthorized access, steal data, establish persistence, or conduct malicious activities. Unlike traditional attacks that often rely on malware deployment, SaaS attacks frequently leverage legitimate functionality that already exists within cloud applications.
Common targets include:

• Microsoft 365
• Google Workspace
• Salesforce
• Slack
• GitHub
• Dropbox
• ServiceNow
• Jira
• Box

Attackers understand that these platforms often contain sensitive emails, intellectual property, source code, credentials, financial information, and internal business communications. As organizations continue moving workloads to the cloud, SaaS platforms have become increasingly attractive targets.

 One of the biggest advantages for attackers is that many SaaS attacks require little or no malware.

Instead of exploiting endpoints, attackers may simply:

Steal credentials

• Hijack sessions
• Abuse OAuth applications
• Exploit weak access controls
• Use compromised third-party integrations

Because the attacker is often using legitimate authentication mechanisms, traditional malware-based detections may never trigger. This significantly reduces visibility for security teams relying heavily on endpoint-centric defenses.

Many SaaS attacks closely resemble normal business operations.

Consider a user who:

• Logs into Microsoft 365
• Opens email
• Downloads files
• Shares documents
• Creates forwarding rules

These are all legitimate actions. Unfortunately, they are also actions an attacker may perform after compromising an account.This makes distinguishing between legitimate activity and malicious behavior much more difficult. The challenge is no longer identifying malware. The challenge becomes identifying abnormal behavior within otherwise legitimate activity.

Many organizations still struggle to maintain consistent visibility across SaaS environments.

Security teams may have excellent monitoring for:

• Endpoints
• Firewalls
• Servers
• Active Directory

But limited visibility into:

• OAuth permissions
• Third-party applications
• Cloud authentication events
• SaaS administrative actions
• Data-sharing activities

Attackers frequently exploit these visibility gaps to operate unnoticed for extended periods.

Common SaaS Attack Techniques

OAuth Consent Abuse

OAuth consent attacks have become one of the most effective methods for compromising SaaS environments. Instead of stealing passwords, attackers create malicious applications and trick users into granting permissions. A victim may receive what appears to be a legitimate Microsoft 365 application request.
Once approved, the attacker may gain access to:

• Emails
• Contacts
• Calendars
• Files
• User profile data

Importantly, this access often survives password changes because the attacker is operating through the authorized application rather than directly through stolen credentials. This makes OAuth abuse particularly dangerous.

Business Email Compromise (BEC)

Business Email Compromise remains one of the most financially damaging attack techniques.

After gaining access to an email account, attackers may:

• Monitor communications
• Hijack conversations
• Request fraudulent payments
• Redirect invoices
• Harvest additional credentials

Because the attacker is operating from a legitimate mailbox, traditional security controls may not immediately identify the activity as malicious.

Stolen Session Tokens

Modern attackers increasingly target authenticated sessions rather than passwords. If a session cookie or authentication token is stolen, an attacker may gain access without needing to authenticate again.

This can effectively bypass security controls such as:

• Password resets
• MFA prompts
• Conditional access policies

To the SaaS platform, the session may appear completely legitimate.