Ransomware operators abuse legitimate remote administration tools and exploit SmarterMail flaws for initial access and persistence
Ransomware activity is increasingly blending into normal IT operations by combining exploitation of internet-facing software with the use of legitimate remote access and monitoring tools. Huntress reported multiple intrusions tied to the Crazy ransomware gang where attackers deployed Net Monitor for Employees Professional and the SimpleHelp remote support client to maintain persistence, evade detection, and stage for ransomware deployment. The actors installed the monitoring agent via msiexec.exe directly from the vendor site, then used it for interactive control (desktop viewing, file transfer, command execution); they also added redundant access by installing SimpleHelp via PowerShell and disguising binaries with benign-looking names (e.g., vshost.exe) and paths such as C:\ProgramData\OneDriveSvc\OneDriveSvc.exe.
In parallel, ransomware groups have been observed actively exploiting recently patched SmarterTools SmarterMail vulnerabilities that enable unauthenticated compromise of mail servers. SC Media reported that CISA added CVE-2026-24423 to the KEV catalog after it was linked to ransomware campaigns; the flaw enables unauthenticated RCE via SmarterMail’s ConnectToHub API by delivering a malicious OS command from a remote server. A second issue, CVE-2026-23760, allows authentication bypass through the password reset API (force-reset-password) by not validating the old password; ReliaQuest attributed active exploitation of this weakness to a China-based actor tracked as Storm-2603, which reportedly chained the bypass with SmarterMail’s Volume Mount feature to reach RCE, activity assessed as staging consistent with Warlock ransomware operations (even when ransomware was not yet deployed).
Timeline
Feb 11, 2026
Huntress links multiple intrusions to the same Crazy ransomware operator
Huntress assessed that the same operator likely conducted the observed incidents based on a reused filename and overlapping command-and-control infrastructure. Only one of the investigated incidents ultimately resulted in Crazy ransomware deployment.
Feb 11, 2026
Crazy ransomware actor attempts defense evasion and account manipulation
Huntress observed the actor trying to enable the local Windows Administrator account and disable Microsoft Defender by stopping and deleting related services. These actions were part of preparing victim environments for ransomware deployment and possible cryptocurrency theft.
Feb 11, 2026
Crazy ransomware actor deploys remote admin tools for stealthy persistence
In the observed intrusions, the attacker installed Net Monitor for Employees Professional and the SimpleHelp remote access client, disguising some binaries and paths to resemble legitimate software. The tools provided interactive control, file transfer, and command execution while blending in with normal administration.
Feb 11, 2026
Crazy ransomware operator breaches networks using stolen SSL VPN credentials
Huntress reported multiple intrusions attributed to a member of the Crazy ransomware gang that began with compromised SSL VPN credentials. The actor used the access to establish footholds in corporate environments and prepare follow-on malicious activity.
Feb 10, 2026
CISA adds CVE-2026-24423 to the KEV catalog after active exploitation
CISA added SmarterMail vulnerability CVE-2026-24423 to its Known Exploited Vulnerabilities catalog after observing it being actively exploited in ransomware campaigns. The flaw allows OS command execution from a remote server through the ConnectToHub API.
Feb 10, 2026
Attackers scan SmarterMail ConnectToHub API for CVE-2026-24423 exploitation
ReliaQuest also observed suspicious ConnectToHub API calls indicating scanning or attempted exploitation of CVE-2026-24423, potentially by a different threat actor than Storm-2603. The activity suggested broader interest in the newly patched SmarterMail vulnerabilities.
Feb 10, 2026
Storm-2603 exploits SmarterMail flaw and stages for Warlock ransomware
ReliaQuest observed a China-based ransomware actor tracked as Storm-2603 exploiting CVE-2026-23760, abusing SmarterMail's Volume Mount feature to escalate to remote code execution, and installing Velociraptor via an MSI hosted on Supabase. The activity was assessed as consistent with staging for Warlock ransomware deployment.
Feb 10, 2026
SmarterTools patches two critical SmarterMail vulnerabilities
SmarterTools recently patched two critical SmarterMail flaws: CVE-2026-23760, an authentication bypass in the password reset endpoint, and CVE-2026-24423, which can enable unauthenticated remote code execution via the ConnectToHub API. Defenders were advised to upgrade to SmarterMail Build 9511.
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