Security researchers have uncovered a set of critical vulnerabilities in Microsoft Teams that could have allowed threat actors to impersonate colleagues, alter messages invisibly, and exploit trust within enterprise communications.
Serious Trust Manipulation Risks
According to a report from Check Point, the flaws—collectively tracked under CVE-2024-38197—enabled attackers to manipulate message content and notifications without displaying the “Edited” label or changing sender identity.
This meant that a malicious actor could send or modify messages to make them appear as though they were coming from a trusted executive or co-worker—potentially tricking victims into clicking malicious links or sharing confidential data.
Cedonix cybersecurity analysts warn that this class of vulnerability goes beyond technical risk: it represents a psychological attack vector, exploiting the human element of trust within workplace collaboration tools.
“We’ve seen a rising trend where adversaries don’t need to break into networks — they simply bend digital trust,” said a Cedonix spokesperson. “Enterprise communication tools like Microsoft Teams are now as mission-critical as email, and they require the same level of security oversight, auditing, and anomaly detection.”
How the Exploit Worked
The flaws affected both internal users and external guests, allowing for:
- Message manipulation without detection.
- Edited or spoofed sender identities in chat notifications.
- Altered display names during calls, enabling caller ID forgery.
These issues undermined collaboration integrity and could have been weaponized for social engineering, credential harvesting, or privilege escalation.
Microsoft’s Response
Microsoft partially addressed the vulnerabilities in August 2024, with additional patches rolled out in September 2024 and October 2025.
The company rated the issue as medium severity (CVSS 6.5), describing it as a spoofing vulnerability impacting Teams for iOS.
In a recent advisory, Microsoft acknowledged that Teams’ “extensive collaboration features and global adoption” make it a prime target for cybercriminals and state-sponsored actors alike — noting that chat, video, and file-sharing functions are being increasingly abused in multi-stage phishing and ransomware campaigns.
Cedonix Recommendation
Cedonix recommends that all organizations:
- Enforce Zero Trust communication policies inside collaboration platforms.
- Deploy behavioral threat monitoring for Microsoft 365 and Teams environments.
- Regularly audit user permissions, especially external guest accounts.
- Integrate advanced endpoint detection solutions to identify lateral movement attempts stemming from compromised collaboration sessions.
“As work becomes more decentralized, trust becomes the new attack surface,” Cedonix experts emphasize. “Verifying what people see is now just as vital as protecting what systems store.”
Source: The Hacker News – “Microsoft Teams Bugs Let Attackers Impersonate Colleagues and Edit Messages Unnoticed”
Adapted for the Cedonix Cybersecurity News Blog
