Threat Profile: Medusa Ransomware & Storm-1175

Danger

Executive Summary: Medusa is a prolific Ransomware-as-a-Service (RaaS) operation that surged in notoriety throughout 2025 and 2026. While the core Medusa developers maintain the encryption payloads and the extortion infrastructure, the actual network intrusions are conducted by highly skilled affiliates. Recent threat intelligence from Microsoft and CybelAngel highlights Storm-1175, a specific, hyper-aggressive affiliate utilizing the Medusa payload. Storm-1175 specializes in compromising vulnerable web-facing assets and executing a devastating 24-hour attack cycle—from initial access to total domain encryption. Defending against this actor requires an immediate paradigm shift in edge appliance monitoring and rapid DFIR triage.

1. Threat Actor Profile: The Storm-1175 Affiliate

In the modern ransomware ecosystem, the malware payload itself is often less interesting than the operator deploying it. Microsoft Threat Intelligence tracks the most effective Medusa affiliate under the identifier Storm-1175.

Unlike “living off the land” purists or slow-moving espionage APTs, Storm-1175 operates with a “smash-and-grab” operational tempo. According to CISA (AA25-071a) and Microsoft research, Storm-1175 completely bypasses traditional phishing campaigns. Instead, they operate an automated, continuous scanning infrastructure that targets unpatched, internet-facing edge appliances.

Primary Targets:

• Vulnerable VPN gateways (e.g., Ivanti Connect Secure, Fortinet, Palo Alto GlobalProtect).
• Exposed RDP endpoints.
• Unpatched web applications susceptible to Remote Code Execution (RCE).

Once Storm-1175 exploits an edge device, they do not attempt to establish long-term, stealthy persistence. They immediately pivot to active data exfiltration and encryption.

2. The 24-Hour Kill Chain

Research published by CybelAngel in 2026 formally documented the Storm-1175 24-Hour Attack Cycle. The adversary relies on heavy automation to minimize the dwell time, leaving Security Operations Centers (SOC) with an exceptionally narrow window to detect and contain the breach.

1. Initial Access (Hour 0): Storm-1175 exploits an N-day vulnerability on a perimeter appliance, instantly dropping a web shell to establish a foothold.
2. Reconnaissance & Privilege Escalation (Hour 1-4): The attacker uses automated scripts to dump local credentials from the compromised appliance and immediately tests them against internal Active Directory services via SMB or RDP. They leverage LOLBAS like net.exe and nltest.exe to map the domain.
3. Data Exfiltration (Hour 5-18): Instead of meticulously searching for specific intellectual property, Storm-1175 performs bulk data extraction. They deploy heavily multi-threaded instances of Rclone or MEGAsync to rapidly push file shares and database backups to attacker-controlled cloud storage.
4. Impact / Encryption (Hour 19-24): Upon confirming the exfiltration is complete, the Medusa ransomware payload is deployed across the network, often using legitimate management tools (like PDQ Deploy) or compromised Domain Controller Group Policies (GPO) to ensure simultaneous execution across all endpoints.

3. The Medusa Payload & Extortion Escalation

The Medusa ransomware payload (encrypting files with the .MEDUSA extension and dropping the !!!READ_ME_MEDUSA!!!.txt ransom note) is highly optimized. It terminates backup services (Veeam, Backup Exec), kills database processes (SQL, Exchange) to release file locks, and clears Volume Shadow Copies using vssadmin.exe.

The V2 Leak Infrastructure

As analyzed by Palo Alto’s Unit 42, the Medusa syndicate escalated their extortion tactics in 2026 by deploying a highly sophisticated “V2” leak site on the Tor network.

To maximize psychological pressure on victims, the new leak site includes:

• Media-Rich Extortion: Pre-rendering sensitive, stolen documents as easily readable galleries directly on the leak site.
• The Extortion Timer: A countdown clock with specific, monetized options for the victim (e.g., “Add 1 day to timer for $10,000”, “Delete all data for $1,000,000”, or “Download all data now for $1,000,000”).
• Public Telegram Channels: Cross-posting victim details to public Telegram channels to alert journalists and stakeholders immediately, weaponizing public relations.

4. Forensic Triage & DFIR Strategy

Because the Storm-1175 attack cycle is so rapid, DFIR analysts cannot afford to wait for the encryption event. The focus must be on detecting the initial perimeter breach and the bulk exfiltration phase.

A. Edge Appliance Log Hunting

Analysts must continuously monitor edge devices. If an Ivanti or Fortinet appliance is in your architecture, search the web access logs for sudden drops of .jsp, .php, or .sh files in temporary web directories, which indicate the initial Storm-1175 webshell deployment.

B. Hunting for Bulk Exfiltration

The 13-hour exfiltration window is the Blue Team’s best opportunity to halt the attack. Review firewall and DNS logs for anomalous outbound traffic originating from internal file servers (which normally only serve internal clients) connecting directly to cloud storage domains (mega.nz, api.dropbox.com, etc.). Refer to our Linux Data Staging & Exfiltration Guide for identifying orphaned rclone binaries in /tmp directories.

5. Detection Rules

KQL (Storm-1175 Edge Exploitation)

hunt_storm1175_edge_compromise.kql

// Detects anomalous child processes spawned by edge web services
// Indicating initial access and webshell execution by Storm-1175
DeviceProcessEvents
| where InitiatingProcessFileName in~ ("w3wp.exe", "httpd", "nginx", "tomcat")
| where FileName in~ ("cmd.exe", "powershell.exe", "sh", "bash", "wget", "curl")
// Filter for execution originating from common web directories or temp folders
| where ProcessCommandLine has_any ("/tmp/", "/var/tmp/", "C:\\inetpub\\wwwroot", "C:\\Windows\\Temp")
| project TimeGenerated, DeviceName, InitiatingProcessFileName, FileName, ProcessCommandLine
| sort by TimeGenerated desc

Sigma (Medusa Ransomware Execution)

sigma_medusa_encryption_behavior.yaml

title: Medusa Ransomware Pre-Encryption Activity
id: 4e5f6a7b-8c9d-0e1f-2a3b-4c5d6e7f8a9b
status: stable
description: Detects the specific sequence of commands executed by the Medusa ransomware payload to inhibit system recovery and kill database services prior to encryption.
logsource:
    category: process_creation
    product: windows
detection:
    selection_vssadmin:
        Image|endswith: '\vssadmin.exe'
        CommandLine|contains|all:
            - 'delete'
            - 'shadows'
    selection_bcdedit:
        Image|endswith: '\bcdedit.exe'
        CommandLine|contains|all:
            - 'set'
            - 'recoveryenabled'
            - 'No'
    selection_services:
        Image|endswith: '\net.exe'
        CommandLine|contains: 'stop'
        CommandLine|contains|any:
            - 'sql'
            - 'msexchange'
            - 'veeam'
    condition: selection_vssadmin or selection_bcdedit or selection_services
level: critical
tags:
    - attack.impact
    - attack.t1490

6. Conclusion and Remediation

The emergence of hyper-accelerated affiliates like Storm-1175 completely invalidates the old paradigm where a network intrusion could lay dormant for months before encryption. With a 24-hour kill chain, organizations cannot rely on manual threat hunting alone.

Remediation requires implementing strict Network Micro-segmentation (preventing edge appliances from reaching internal active directory servers over SMB/RDP) and enforcing behavioral blocks on unauthorized exfiltration tools like rclone.

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Sources & References

• CISA Advisory: #StopRansomware: Medusa Ransomware (AA25-071a)
• Microsoft Security (2026): Storm-1175 focuses gaze on vulnerable web-facing assets in high-tempo Medusa operations
• CybelAngel Threat Research (2026): Storm-1175’s 24-hour attack cycle
• Palo Alto Unit 42: Medusa Ransomware Escalation & New Leak Site
• Related Playbook: Ransomware Investigation