In early 2026, a ransomware attack attributed to the Iranian state-sponsored hacking group MuddyWater was observed by Rapid7. The attack is described as a ‘false flag’ operation, where the attackers used social engineering techniques via Microsoft Teams to initiate the infection sequence. As reported by The Hacker News, the attackers exploited the platform’s collaboration features to steal sensitive information and execute malicious scripts.
Key Takeaways
- The attack was attributed to the Iranian state-sponsored hacking group MuddyWater.
- The attackers used social engineering techniques via Microsoft Teams to initiate the infection sequence.
- The attack is described as a ‘false flag’ operation.
- Rapid7 observed the attack in early 2026.
- The attackers exploited Microsoft Teams’ collaboration features to steal sensitive information and execute malicious scripts.
The False Flag Ransomware Attack
The attack observed by Rapid7 in early 2026 is a prime example of a ‘false flag’ operation, where the attackers created a fictional narrative to distract from their true intentions. According to The Hacker News, the attackers used Microsoft Teams to send unsolicited messages to potential victims, which contained malicious scripts that stole sensitive information.
False flag attacks aren’t new, but their use in ransomware campaigns marks a shift in how state-sponsored actors operate. Instead of leaving behind digital fingerprints that point to their origin, groups like MuddyWater are now crafting narratives that mimic financially motivated cybercriminals. In this case, the ransomware component looked like a typical data-encrypting payload demanding cryptocurrency. But deeper analysis suggested the real goal wasn’t money—it was intelligence gathering.
The attackers mimicked the behavior of known ransomware-as-a-service (RaaS) groups, using double-extortion tactics: encrypting files and threatening to leak stolen data. But unlike most ransomware actors, they didn’t aggressively follow up on payment demands. That inconsistency tipped off Rapid7 analysts. The ransom note appeared almost as an afterthought—less a business transaction, more a smokescreen.
The social engineering component was delivered through Microsoft Teams’ chat interface, targeting employees in mid-level IT and finance roles. Messages were tailored to appear as internal communications, often referencing non-existent meetings, budget approvals, or urgent software updates. The lures included links to fake SharePoint documents or embedded scripts within Teams tabs—trusted features that don’t typically raise red flags.
Once clicked, the scripts initiated a chain of events: credential harvesting, lateral movement across the network, and eventual access to sensitive repositories. The attackers moved slowly, avoiding noisy actions that might trigger automated detection systems. This patience is typical of state-sponsored operations, where long-term access is valued over quick payouts.
Microsoft Teams Vulnerability
The attack highlights a vulnerability in Microsoft Teams’ collaboration features, which allowed the attackers to exploit the platform and steal sensitive information. The attackers used the platform’s built-in features to create a convincing narrative, which was designed to trick potential victims into executing malicious scripts.
Microsoft Teams, like many collaboration platforms, prioritizes ease of use and integration. Tabs, apps, and file-sharing tools are deeply embedded into workflows. That’s great for productivity—but dangerous when abused. The attackers didn’t rely on zero-day exploits. They didn’t need to. They used Teams’ native functionality in ways that bypassed traditional email filters and endpoint protections.
For example, malicious scripts were embedded in custom app tabs that mimicked internal dashboards. Because these apps were added to legitimate team channels, they appeared authorized. Users didn’t have to download attachments or click suspicious links—they just opened a tab they assumed was safe. The scripts ran in the context of the user’s session, harvesting authentication tokens and accessing linked services like OneDrive, SharePoint, and Exchange Online.
Another technique involved spoofing sender identities within Teams’ internal messaging. Unlike email, where spoofing often triggers DMARC or SPF checks, Teams doesn’t have the same level of identity validation between tenants in federated environments. That allowed attackers to impersonate trusted colleagues, even across organizational boundaries.
The problem isn’t that Microsoft Teams is insecure—it’s that its trust model assumes internal actors are legitimate. When an attacker gains a single foothold, either through phishing or compromised credentials, they inherit that trust. From there, they can deploy malicious apps, send messages, and access data without triggering alarms.
Organizations often disable external access controls to simplify collaboration. That convenience opens the door. In this attack, Muddywater likely gained initial access through a third-party vendor with Teams connectivity, then pivoted into the primary target. Once inside, they used Teams as both a command-and-control channel and a data exfiltration pathway—masking their traffic as normal collaboration activity.
The Impact of the Attack
The impact of the attack is still being assessed, but the attackers exploited a vulnerability in Microsoft Teams to steal sensitive information. The fact that the attack was attributed to MuddyWater, an Iranian state-sponsored hacking group, raises concerns about the level of sophistication and resources available to these groups.
Initial reports suggest data was exfiltrated from at least three organizations in the defense and energy sectors. The stolen information included internal communications, technical schematics, and employee directories—materials more useful for espionage than ransom negotiations. No encryption events were observed in two of the three cases, further suggesting the ransomware element was a cover.
MuddyWater has a history of targeting government and private sector entities in the Middle East, Europe, and North America. The group, also known as Static Kitten or MERCURY, has been active since at least 2017. They’ve previously used phishing, DNS tunneling, and compromised routers to gain access. What’s different now is their pivot to cloud-native platforms—especially collaboration tools used by remote and hybrid teams.
Their shift reflects a broader trend. As companies move to the cloud, attackers follow. Email gateways are well-defended. Endpoints are monitored. But collaboration platforms like Teams, Slack, and Google Workspace sit in a gray area—critical to operations, yet often under-secured. Permissions are overly broad, logging is inconsistent, and detection rules are outdated.
The long-term implications are serious. If attackers can weaponize trusted collaboration tools, they can remain undetected for months. They can gather intelligence, map network structures, and identify high-value targets—all while appearing as normal users. That’s not just a breach. It’s a sustained occupation.
Rapid7’s Observations
Rapid7’s observations of the attack provide valuable insights into the tactics and techniques used by the attackers. According to The Hacker News, Rapid7 noted that the attackers used a combination of social engineering and exploitation of Microsoft Teams’ collaboration features to initiate the infection sequence.
The security firm detected unusual API calls from Microsoft Teams apps, particularly around token usage and app registration. They also observed spikes in file access from users who hadn’t logged in via browser or desktop client—indicating session hijacking. In one case, a single compromised account accessed over 12,000 files across SharePoint and OneDrive in a 72-hour window.
Rapid7 emphasized that the attack wasn’t about breaking in—it was about blending in. The attackers didn’t use malware in the traditional sense. No droppers, no loaders. Just scripts executed in browser sessions, using legitimate cloud APIs. That makes detection harder, especially for organizations relying on signature-based tools.
The firm also pointed to delayed detection windows. On average, organizations took 47 days to identify the malicious activity—far longer than the typical ransomware timeline. That delay gave attackers time to explore, escalate privileges, and establish backdoors.
Rapid7 recommended enhanced logging for Microsoft 365 environments, stricter app permission policies, and user training focused on in-platform threats—not just email. They also urged companies to treat collaboration platforms as part of their core attack surface, not just productivity tools.
What This Means For You
The attack highlights the importance of staying vigilant and being aware of the tactics and techniques used by attackers. It is essential to be cautious when using collaboration platforms like Microsoft Teams, especially when receiving unsolicited messages or requests. It is crucial to keep software and systems up to date to prevent exploitation of known vulnerabilities.
For developers, this means rethinking how third-party apps are integrated into collaboration platforms. If you’re building an app for Teams, you can’t assume the platform handles security. You need to enforce least-privilege permissions, log user actions, and validate authentication tokens on every request. A malicious actor with a stolen token shouldn’t be able to impersonate your app or access user data unchecked.
Founders and startup leaders should consider their vendor risk. Many small companies connect their tools to larger partners’ Teams environments. That connection is a two-way street. A breach at your startup could become a backdoor into a major client. Investors are starting to ask about cloud collaboration security during due diligence. If you can’t show strong access controls and monitoring, you’re a liability.
For enterprise builders—security teams, IT managers, system architects—this attack is a wake-up call. You can’t treat Teams like a chat app. It’s an enterprise system with deep access to your data. You need to audit app installations regularly, limit external messaging, and enable detailed logging in Microsoft 365. Conditional access policies should block logins from unfamiliar devices or locations. And you need to simulate attacks—run red team exercises that test Teams-specific threats.
Training also needs to evolve. Most phishing simulations focus on email. But in 2026, the most dangerous message might not be in your inbox—it could be a DM in Teams from “Sarah in HR” asking you to review a document. Employees need to know that urgency + unfamiliar request = stop and verify. Even if it looks real.
Historical Context
MuddyWater isn’t new. The group has been active for nearly a decade, often linked to Iran’s Islamic major Guard Corps (IRGC). They’ve targeted telecoms, government agencies, and energy firms across Turkey, Israel, Saudi Arabia, and the U.S. Their tools are often crude, relying on open-source malware and publicly available hacking frameworks. But their persistence makes them dangerous.
What’s changed is their target set. In the past, MuddyWater used brute-force attacks and router exploits. Now, they’re moving up the stack—using cloud platforms, APIs, and social engineering. This mirrors a broader shift in cyber espionage. Nation-state actors are no longer just hacking networks. They’re hacking workflows.
The 2026 Teams attack follows a pattern seen in earlier incidents. In 2023, another Iranian group used Slack phishing to target defense contractors. In 2024, Chinese-affiliated hackers abused Google Workspace apps to infiltrate think tanks. Each time, the attackers used the platform’s trust model against itself.
Collaboration tools have become the soft underbelly of enterprise security. They’re designed to be open, flexible, and easy to use. That’s their strength—and their weakness. As long as organizations prioritize convenience over control, attackers will keep finding ways in.
Looking Ahead
As the cybersecurity landscape continues to evolve, it is essential to stay one step ahead of attackers. The attack observed by Rapid7 in early 2026 is a prime example of the level of sophistication and resources available to attackers. It is crucial to be aware of the tactics and techniques used by attackers and to stay vigilant when using collaboration platforms like Microsoft Teams.
Organizations will need to shift from perimeter-based security to identity-centric models. The network boundary no longer exists. Your employees work from anywhere, on any device, using dozens of cloud apps. Protection has to follow the user—and the session.
Microsoft has started rolling out enhanced app governance tools for Teams, including stricter consent prompts and automated anomaly detection. But adoption is slow. Many organizations haven’t enabled these features, either due to complexity or fear of disrupting workflows.
The bigger challenge is cultural. Security teams need to collaborate with HR, IT, and executive leadership to treat collaboration platforms as critical infrastructure. That means budget, training, and oversight.
One thing’s clear: the days of ignoring in-app threats are over. The next major breach might not come through email. It might come through a message that says, “Hey, can you check this report when you get a sec?”
Sources: The Hacker News, Rapid7
A darkened conference room with a single spotlight shining on a Microsoft Teams logo displayed on a large screen, with a faint hum of activity emanating from the background as the cybersecurity team works tirelessly to uncover the truth behind the MuddyWater attack.
