🛡️ Threat Analysis • Collaboration Platform Security

Beyond Phishing: How Threat Actors Are Weaponizing Native Microsoft Teams Capabilities for Malware Delivery

By CyberDudeBivash • October 07, 2025 • Strategic Threat Report

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Threat Report: Table of Contents

Chapter 1: The New Insider Threat — When Teams Itself is the Attack Vector

For years, we’ve trained our employees to be suspicious of external emails. But what happens when the attack originates from inside your most trusted collaboration tool? Threat actors are evolving beyond traditional phishing and are now “living off the trusted platform,” weaponizing native Microsoft Teams capabilities to deliver malware. By abusing features like **Incoming Webhooks** and **Adaptive Cards**, they can craft malicious messages that appear as legitimate, automated system notifications within a trusted Teams channel. This bypasses the user’s natural skepticism and creates a dangerous new vector for initial access.

Chapter 2: The Kill Chain — Abusing Webhooks and Adaptive Cards

The attack is a sophisticated two-part social engineering ploy.

1. Abusing Incoming Webhooks for Impersonation

An Incoming Webhook is a legitimate Teams feature that provides a unique URL to a channel, allowing external services to post messages. An attacker first needs to obtain this URL, either by compromising a user account, tricking a user into creating one for them, or finding one leaked in a public code repository. With this URL, they can send any message they want to the channel, and it will appear to be an official, automated notification, complete with a custom name and icon (e.g., “SharePoint Updates”).

2. Weaponizing Adaptive Cards for Payload Delivery

Instead of a simple message with a link, the attacker uses the webhook to post a rich, interactive **Adaptive Card**. They craft the card to look identical to a legitimate file notification from SharePoint or OneDrive. It will show a file icon, a filename, and a friendly “Open” button. However, the action behind this “Open” button is programmed to point to the attacker’s malicious payload—often a ZIP file containing a malicious LNK—hosted on an external site.

Chapter 3: The Defender’s Playbook — Hardening and Hunting in Teams

Defending against the abuse of legitimate features requires a new layer of governance and detection.

1. Audit and Control Webhooks

In your Microsoft Teams Admin Center, you must regularly audit all configured Incoming Webhooks. Understand who created them and for what purpose. Restrict the ability to create new webhooks to a limited group of administrators and have a formal approval process.

2. Scan Internal Communications

Your security stack must have visibility *inside* your collaboration tools. A modern security solution for Microsoft 365 can scan messages and files shared within Teams in real-time, detecting malicious links or attachments even if they come from a seemingly trusted internal source like a webhook.

Secure Your Collaboration Suite: Protecting your M365 environment requires a purpose-built tool. **Kaspersky Security for Microsoft Office 365** is designed to provide this critical layer of defense, scanning emails, files, and Teams messages for threats.

3. Hunt for the Post-Compromise Behavior

Your EDR is your ultimate safety net. You must assume a user will eventually click. The key threat hunt is to look for the Teams process (`Teams.exe`) spawning anomalous child processes. Teams should never be the parent of `powershell.exe`, `cmd.exe`, or `mshta.exe`.

Chapter 4: The Strategic Takeaway — Zero Trust for Your Collaboration Tools

This new TTP is a powerful lesson in the necessity of a **Zero Trust** mindset. We can no longer implicitly trust messages just because they originate from “inside” our collaboration platform. Every link, every attachment, and every interactive card—regardless of its source—must be treated as potentially hostile.

For CISOs, this means your security strategy must extend beyond the email gateway and the network perimeter. You must have deep visibility and control within your core SaaS applications. The assumption must be that an attacker is already inside, and your defenses must be built to detect their actions, even when they are using your own trusted tools against you.

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About the Author

CyberDudeBivash is a cybersecurity strategist with 15+ years in application security, incident response, and cloud security architecture, advising CISOs across APAC. [Last Updated: October 07, 2025]

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