Top 5 Cybersecurity News Stories December 26, 2025
Cybersecurity threats are constantly evolving as threat actors seek access to your data and money. To help you stay secure, we have searched the internet for the top five cybersecurity news stories of the week that we think you should be aware of. No story is too big or small as we look at threats from espionage to security flaws in everyday devices:
1. Microsoft Teams to let admins block external users via Defender portal
Microsoft is introducing a new feature in Teams that allows administrators to block external users directly through the Microsoft Defender portal. This enhancement aims to strengthen organizational security by preventing unauthorized access and reducing exposure to potential phishing or social engineering attacks.
Admins will have centralized control, making it easier to enforce collaboration policies and protect sensitive data. The feature integrates seamlessly with existing security tools, ensuring streamlined management without disrupting workflows. Organizations are encouraged to review their external collaboration settings and prepare for deployment to maximize security benefits.
Read more on BleepingComputer
2. New MacSync macOS Stealer Uses Signed App to Bypass Apple Gatekeeper
A newly discovered malware called MacSync targets macOS systems by leveraging a signed binary to bypass security controls. This stealer focuses on harvesting sensitive data, including credentials and system information, while maintaining stealth through legitimate code signing.
Researchers warn that the malware is distributed via deceptive installers and phishing campaigns, posing a significant risk to macOS users. The use of signed binaries makes detection challenging, emphasizing the need for robust endpoint monitoring and user awareness. Security teams should prioritize behavioral analysis and update defenses to counter evolving macOS threats.
Read more on The Hacker News
3. Fake MAS Windows activation domain used to spread PowerShell malware
Cybercriminals are exploiting a fake Microsoft Activation Script (MAS) domain to distribute PowerShell-based malware. The campaign tricks users seeking activation tools into downloading malicious scripts that enable remote access and data theft.
This tactic highlights the dangers of using unofficial activation utilities, which often serve as vectors for sophisticated attacks. Researchers advise organizations and individuals to avoid pirated or third-party activation tools and maintain strict software compliance. Enhanced email filtering and endpoint protection can help mitigate risks associated with these deceptive campaigns.
Read more on BleepingComputer
4. MongoDB warns admins to patch severe RCE flaw immediately
MongoDB has issued an urgent advisory regarding a critical remote code execution vulnerability affecting its database software. The flaw, if exploited, allows attackers to execute arbitrary commands and potentially gain full control over affected systems.
Organizations using MongoDB are strongly urged to apply the latest patches without delay to prevent compromise. This vulnerability underscores the importance of timely updates and rigorous security practices for database environments. Failure to patch could lead to data breaches and operational disruptions, making immediate remediation essential for risk mitigation.
Read more on BleepingComputer
5. Two Chrome Extensions Caught Secretly Stealing Credentials from Over 170 Sites
Two Chrome extensions were discovered secretly harvesting sensitive user data, including authentication tokens and browsing activity, posing significant security risks. The extensions, installed by thousands, exploited permissions to access private information and transmit it to remote servers without consent.
Google has removed both from the Chrome Web Store, but users are urged to uninstall them immediately and review account security. This incident underscores the importance of scrutinizing browser extensions and implementing strict permission controls to prevent data exfiltration and potential account compromise.
Read more on The Hacker News
At DIESEC, our experts are ready to assist with all your cybersecurity needs. We ensure your system is safe and secure and provide training for your employees to avoid falling victim to social engineering tactics.
For more information, please contact us now!
