Critical

Hackers Use Compromised ConnectWise Credential to Sign In to 173 Microsoft 365 Tenants

The Hacker News
Actively Exploited

Overview

Cybersecurity researchers have identified an ongoing campaign where hackers are using compromised Microsoft 365 credentials from ConnectWise Cloud Backup to access the M365 environments of 173 customers. ConnectWise Cloud Backup, previously known as SkyKick, is a service designed for managed service providers to offer cloud-based backup solutions. The attackers are exploiting these stolen credentials to gain unauthorized entry, which poses a significant risk to the affected organizations. This incident not only compromises sensitive data but also raises concerns about the security protocols in place for cloud services used by MSPs. Companies relying on these services should review their security practices and monitor for any unusual activity in their accounts.

Key Takeaways

  • Active Exploitation: This vulnerability is being actively exploited by attackers. Immediate action is recommended.
  • Affected Systems: Microsoft 365, ConnectWise Cloud Backup
  • Action Required: Organizations should immediately review and reset any compromised credentials, enforce multi-factor authentication, and monitor for suspicious activity in their Microsoft 365 accounts.
  • Timeline: Newly disclosed

Original Article Summary

Cybersecurity researchers are sounding the alarm related to an active campaign in which unknown threat actors are abusing a compromised Microsoft 365 (M365) credential belonging to ConnectWise Cloud Backup (formerly SkyKick) to gain unauthorized access to customers' M365 environments. ConnectWise Cloud Backup is a cloud-based backup and recovery service built for managed service providers (MSPs

Impact

Microsoft 365, ConnectWise Cloud Backup

Exploitation Status

This vulnerability is confirmed to be actively exploited by attackers in real-world attacks. Organizations should prioritize patching or implementing workarounds immediately.

Timeline

Newly disclosed

Remediation

Organizations should immediately review and reset any compromised credentials, enforce multi-factor authentication, and monitor for suspicious activity in their Microsoft 365 accounts.

Additional Information

This threat intelligence is aggregated from trusted cybersecurity sources. For the most up-to-date information, technical details, and official vendor guidance, please refer to the original article linked below.

Related Topics: This incident relates to Microsoft.

Related Coverage

ShadowPad Malware Actively Exploits WSUS Vulnerability for Full System Access

The Hacker News

The ShadowPad malware is exploiting a recently patched vulnerability in Microsoft Windows Server Update Services (WSUS), identified as CVE-2025-59287, allowing attackers to gain full system access. This exploitation highlights the critical need for organizations to promptly apply security updates to vulnerable systems to prevent unauthorized access.

Nov 24, 2025

⚡ Weekly Recap: Fortinet Exploit, Chrome 0-Day, BadIIS Malware, Record DDoS, SaaS Breach & More

The Hacker News

This week, significant cybersecurity threats emerged as hackers exploited new 0-day vulnerabilities in Fortinet and Chrome, infiltrating supply chains and SaaS tools. The rapid response from major companies like Microsoft, Salesforce, and Google highlights the severity of these attacks and the ongoing challenges in securing trusted applications and software updates.

Nov 24, 2025

Microsoft Highlights Security Risks Introduced by New Agentic AI Feature

SecurityWeek

Microsoft has raised concerns about the security risks associated with its new Agentic AI feature, highlighting the potential for AI agents to engage in malicious activities like data exfiltration and malware installation if not properly secured. This underscores the critical need for robust security controls to mitigate these risks.

Nov 24, 2025

ToddyCat’s New Hacking Tools Steal Outlook Emails and Microsoft 365 Access Tokens

The Hacker News

ToddyCat, a threat actor, has developed a new tool called TCSectorCopy to steal Outlook emails and Microsoft 365 access tokens by exploiting the OAuth 2.0 authorization protocol through users' browsers. This poses a significant threat to corporate email security, as it allows unauthorized access to sensitive information outside the compromised infrastructure.

Nov 25, 2025

Microsoft: Security keys may prompt for PIN after recent updates

BleepingComputer

Microsoft has alerted users that FIDO2 security keys may require a PIN for sign-in following recent Windows updates since September 2025. This change could affect user experience and security practices, particularly for those relying on these security keys for authentication.

Nov 26, 2025

Microsoft to secure Entra ID sign-ins from script injection attacks

BleepingComputer

Microsoft is set to enhance the security of its Entra ID authentication system to protect against external script injection attacks starting in mid-to-late October 2026. This improvement aims to mitigate potential vulnerabilities that could be exploited by attackers to compromise user sign-ins.

Nov 26, 2025