THEGENTLEMEN Ransomware: Global Healthcare & Tech Surge — Critical Exploit Analysis

Date: 2026-06-09 Analyst: Security Arsenal Intelligence Unit Source: Dark Web Leak Site Surveillance (.onion)

Threat Actor Profile — THEGENTLEMEN

The Gentlemen operate as an aggressive Ransomware-as-a-Service (RaaS) entity characterized by a professionalized "customer service" approach to negotiations. Unlike closed groups, they appear to recruit affiliates, evidenced by the wide variance in victim types and geographic locations in a single posting window.

• Known Aliases: The Gentlemen Club (suspected).
• Operating Model: RaaS with affiliate-driven initial access.
• Typical Ransom Demands: Variable, ranging from $500k for small entities to $5m+ for critical infrastructure, often escalating if deadlines are missed.
• Initial Access: Heavily reliant on unpatched perimeter vulnerabilities. Recent intelligence strongly suggests affiliates are weaponizing ConnectWise ScreenConnect (CVE-2024-1708) and Microsoft Exchange (CVE-2023-21529) for initial foothold. Phishing remains a secondary vector.
• Double Extortion: Strict adherence to data theft prior to encryption. They threaten to release sensitive PII (notably in Healthcare) and proprietary source code (Tech).
• Dwell Time: Short. Observations suggest an average of 3-4 days between initial access (via CVE exploit) and encryption detonation.

Current Campaign Analysis

Sector Targeting

The latest data dump (2026-06-08) reveals a pivot toward Healthcare and Technology. Of the 15 victims posted, 3 are confirmed Healthcare providers (WCM Remedium, The Clinic, Central Arkansas Pediatrics) and 3 are Technology firms (Yao Yuan Technology, IP Rings, Jyharn Electronic).

Geographic Dispersion

THEGENTLEMEN are executing a "smash-and-grab" global strategy. Victims span Poland (PL), Japan (JP), Hong Kong (HK), Taiwan (TW), Great Britain (GB), Russia (RU), United States (US), Spain (ES), and Argentina (AR). This lack of geo-focus suggests the group is scanning for specific vulnerable software versions rather than targeting specific regional economies.

Victim Profile

The targets range from mid-market businesses (e.g., local clinics like Central Arkansas Pediatrics) to logistics giants (Integrated Distribution GB). The inclusion of "Not Found" or generic sectors (Danzo Group, Tress) implies the group casts a wide net, encrypting whatever infrastructure they can access.

CVE Connection & TTPs

The group's recent success correlates directly with the CISA KEV list:

• CVE-2024-1708 (ConnectWise): Highly likely used for remote access to Business Services and Logistics firms that rely on remote monitoring and management (RMM) tools.
• CVE-2023-21529 (Exchange): A probable entry point for Healthcare and Education sectors (Institucion Cervantes) where Exchange servers are exposed to the internet.
• CVE-2025-52691 (SmarterMail): Specific targeting of email infrastructure for credential harvesting.

Detection Engineering

SIGMA Rules

---
title: Potential ConnectWise ScreenConnect Auth Bypass
description: Detects potential exploitation of CVE-2024-1708 involving suspicious path traversal or authentication bypass in ScreenConnect logs.
references:
  - https://cisa.gov/known-exploited-vulnerabilities-catalog
author: Security Arsenal
date: 2026/06/09
status: experimental
detection:
  selection:
    service|contains: 'ScreenConnect'
    uri|contains:
      - '/App_Web/'
      - '..%2F'
      - '%2F..'
  condition: selection
falsepositives:
  - Legitimate administrative testing
level: high
---
title: Suspicious Exchange Deserialization Activity
description: Detects potential exploitation of CVE-2023-21529 involving deserialization of untrusted data via Microsoft Exchange Server.
references:
  - https://cisa.gov/known-exploited-vulnerabilities-catalog
author: Security Arsenal
date: 2026/06/09
status: experimental
detection:
  selection_process:
    Image|endswith: '\w3wp.exe'
    Company|contains: 'Microsoft Corporation'
  selection_cmdlet:
    ProcessCommandLine|contains:
      - 'New-Object'
      - 'System.Runtime.Serialization.Formatters.Binary'
      - 'System.Web.UI.LosFormatter'
  condition: all of selection*
falsepositives:
  - Legitimate Exchange Management Scripts
level: high
---
title: Ransomware Pre-Encryption VSS Deletion
description: Detects commands used to delete Volume Shadow Copies often used by ransomware like THEGENTLEMEN to prevent recovery.
author: Security Arsenal
date: 2026/06/09
status: experimental
detection:
  selection:
    Image|endswith:
      - '\vssadmin.exe'
      - '\wmic.exe'
    CommandLine|contains:
      - 'delete shadows'
      - 'shadowcopy delete'
  condition: selection
falsepositives:
  - System administrator maintenance
level: critical

KQL (Microsoft Sentinel)

Hunt for lateral movement and staging behaviors typical of this group.

let TimeFrame = 1h;
DeviceProcessEvents
| where Timestamp > ago(TimeFrame)
// Look for lateral movement tools often used by this group
| where FileName in~ ("psexec.exe", "psexec64.exe", "wmic.exe", "powershell.exe", "cmd.exe")
// Filter for network connection indicators or specific arguments
| where ProcessCommandLine has "\\" and (ProcessCommandLine has "@" or ProcessCommandLine has "/node:")
// Exclude known admins if necessary
| summarize Count() by DeviceName, FileName, AccountName, ProcessCommandLine
| where Count_ > 5

PowerShell Response Script

Rapid-response check for suspicious scheduled tasks added in the last 7 days (a common persistence mechanism for THEGENTLEMEN).

# Check for Scheduled Tasks created/modified in the last 7 days
$DateCutoff = (Get-Date).AddDays(-7)
Get-ScheduledTask | ForEach-Object {
    $Task = $_
    $TaskInfo = $Task | Get-ScheduledTaskInfo
    if ($TaskInfo.LastRunTime -gt $DateCutoff -or $TaskInfo.NextRunTime -gt $DateCutoff) {
        [PSCustomObject]@{
            TaskName = $Task.TaskName
            TaskPath  = $Task.TaskPath
            LastRun  = $TaskInfo.LastRunTime
            NextRun  = $TaskInfo.NextRunTime
            Author   = $Task.Author
            Action   = ($Task.Actions.Execute) -join ', '
        }
    }
} | Format-Table -AutoSize


---

Incident Response Priorities

T-Minus Detection Checklist

1. ScreenConnect Audit: Immediate review of ConnectWise ScreenConnect logs for 2026-06-08 activity matching CVE-2024-1708 path traversal patterns.
2. Exchange IIS Logs: Hunt for anomalous POST requests to /EWS/ or /autodiscover/ resulting in 500 errors (indicative of deserialization crashes).
3. Mass File Modifications: Monitor EDR for processes modifying >50 files/sec within 5 minutes.

Critical Assets at Risk

Based on current victimology:

• Healthcare: EMR/EHR databases and Patient PII.
• Logistics: Supply chain manifests and shipping schedules.
• Technology: Source code repositories and SSH keys.

Containment Actions

1. Disconnect: Isolate identified Exchange and RMM servers from the network immediately if compromise is suspected.
2. Revoke Credentials: Force reset of all local admin credentials on domain controllers and jump servers.
3. Block IP: Implement firewall blocks for known TOR exit nodes and C2 infrastructure associated with THEGENTLEMEN (refer to your Threat Intel Feed).

Hardening Recommendations

Immediate (24 Hours)

• Patch Critical CVEs: Emergency patching of CVE-2024-1708 (ConnectWise) and CVE-2023-21529 (Exchange) is mandatory. If patching is not possible, disable internet-facing access to these services immediately.
• Disable Legacy Protocols: Ensure SMBv1 is disabled across the network to impede lateral movement.
• MFA Enforcement: Enforce phishing-resistant MFA on all VPN, RMM, and OWA logins.

Short-Term (2 Weeks)

• Network Segmentation: Move RMM and Management servers to a dedicated administrative VLAN with strict ingress/egress rules.
• EDR Deployment: Ensure 100% coverage of EDR agents on servers, specifically targeting the Healthcare and Tech sectors identified as high-value targets.

Related Resources

Security Arsenal Incident Response Managed SOC & MDR Services AlertMonitor Threat Detection From The Dark Side Intel Hub