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Introduction:
Storm-1175, a financially motivated ransomware group, is weaponizing recently disclosed “N-day” vulnerabilities in internet-exposed systems to deploy Medusa ransomware within hours—sometimes less than a day. This aggressive campaign targets healthcare, education, professional services, and financial sectors across Australia, the UK, and the US, exploiting the critical window between public vulnerability disclosure and patch deployment. Understanding their TTPs (Tactics, Techniques, and Procedures) and implementing rapid hardening measures is essential to avoid becoming the next victim.
Learning Objectives:
- Identify the specific web-facing vulnerabilities commonly exploited by Storm-1175 and map them to MITRE ATT&CK techniques.
- Execute rapid vulnerability assessment and patch management workflows on Linux and Windows perimeter systems.
- Deploy active defense measures including endpoint detection rules, network segmentation, and ransomware-specific mitigation commands.
You Should Know:
- Rapid Vulnerability Identification & Patching for Web-Facing Services
Storm-1175 scans for internet-exposed services running unpatched software such as Exchange servers, VPN gateways, and RDP. The group focuses on N-day vulnerabilities—flaws with public PoC exploits but not yet widely patched.
Step‑by‑step guide to identify and patch high-risk exposures:
On Linux (e.g., web servers, VPN appliances):
Check for exposed services listening on all interfaces sudo ss -tulpn | grep -E '0.0.0.0:|:::' | grep -E ':(80|443|3389|1723|1194|22)' List installed packages with known critical CVEs (using Debian/Ubuntu) sudo apt update && sudo apt list --upgradable | grep -E 'openssl|nginx|apache2|openssh|samba' For RHEL/CentOS sudo yum check-update | grep -E 'openssl|httpd|sshd|samba' Check for unpatched Exchange-like services (if running on Linux with Wine or similar – rare) Instead, focus on Apache Log4j, Spring4Shell, etc. sudo grep -r "log4j" /opt/ 2>/dev/null Apply critical updates immediately (avoid rebooting if not required) sudo apt upgrade -y --only-upgrade openssl nginx apache2 openssh-server sudo systemctl restart nginx apache2 sshd
On Windows (IIS, RDP, Exchange, SQL Server):
Identify internet-facing network adapters
Get-NetAdapter | Where-Object {$<em>.Status -eq "Up"} | Get-NetIPAddress | Where-Object {$</em>.AddressFamily -eq "IPv4"}
Check for missing security updates using PowerShell
Get-HotFix | Select-Object HotFixID, InstalledOn
Use WMI to query missing updates (requires PSWindowsUpdate module)
Install-Module PSWindowsUpdate -Force
Get-WindowsUpdate -Category "Security Updates" -IsInstalled $false | Out-GridView
Specifically check for Exchange CVEs (e.g., CVE-2024-21410, CVE-2023-23397)
Get-WindowsUpdate -KBArticleID "KB5037224" Example: update for Exchange Server 2019
Patch immediately
Install-WindowsUpdate -AcceptAll -AutoReboot:$false -Category "Security Updates"
For cloud hardening (Azure/AWS):
Azure CLI – list public IPs on VMs az network public-ip list --output table --query "[?ipAddress!=null]" AWS CLI – find security groups allowing 0.0.0.0/0 for RDP (3389) or SSH (22) aws ec2 describe-security-groups --filters Name=ip-permission.cidr,Values='0.0.0.0/0' --query 'SecurityGroups[].[GroupName,IpPermissions[?FromPort==<code>3389</code>||FromPort==<code>22</code>]]'
2. Detecting Medusa Ransomware IOCs and Stopping Encryption
Medusa ransomware leaves specific file extensions (.medusa, .locked, .ransom), creates ransom notes named !READ_ME_MEDUSA!.txt, and attempts to delete shadow copies. Storm-1175 often uses PsExec or WMI for lateral movement.
Step‑by‑step guide to detect and halt Medusa in progress:
On Windows (real-time monitoring and response):
Monitor for suspicious file rename operations (ransomware activity)
Run in elevated PowerShell
$watcher = New-Object System.IO.FileSystemWatcher
$watcher.Path = "C:\Users\Public"
$watcher.IncludeSubdirectories = $true
$watcher.EnableRaisingEvents = $true
Register-ObjectEvent $watcher "Renamed" -Action { Write-Host "Suspicious rename: $($Event.SourceEventArgs.FullPath)" }
Terminate known Medusa processes (if seen)
Get-Process -Name "mshta", "powershell", "cmd", "wmic", "vssadmin" -ErrorAction SilentlyContinue | Stop-Process -Force
Disable volume shadow copy deletion prevention (pre-emptive)
Block vssadmin.exe using AppLocker or modify SACL
icacls C:\Windows\System32\vssadmin.exe /deny "Everyone:(X)"
Immediate recovery: kill ransom process by file handle
Identify process locking files with .medusa extension
handle64.exe -accepteula -a -p .medusa from Sysinternals
On Linux (detect encryption behavior):
Monitor for massive file writes in user directories
inotifywait -m -r -e modify,create --format '%w%f' /home /var/www | while read FILE; do
if file "$FILE" | grep -q "encrypted"; then
echo "ALERT: Potential ransomware activity on $FILE" | wall
Kill suspicious process (e.g., high I/O from unknown binary)
lsof "$FILE" | awk 'NR>1 {print $2}' | xargs kill -9
fi
done
Check for ransom note creation
find / -name "READMEMEDUSA.txt" -type f 2>/dev/null
Block encryption using auditd to monitor write access to critical files
auditctl -w /etc -p wa -k ransomware_defense
auditctl -w /var/lib/mysql -p wa -k ransomware_defense
- Network Segmentation & Firewall Hardening Against Lateral Movement
Storm-1175 moves laterally using RDP, SMB, and WinRM. Isolating critical assets and restricting inbound/outbound traffic can contain an outbreak.
Step‑by‑step guide to implement micro-segmentation:
On Linux (iptables/nftables):
Block all SMB (445) and RDP (3389) from untrusted subnets sudo iptables -A INPUT -p tcp --dport 445 -s 192.168.0.0/16 -j DROP sudo iptables -A INPUT -p tcp --dport 3389 -s 0.0.0.0/0 -j DROP Allow only management jump host sudo iptables -A INPUT -p tcp --dport 22 -s 10.10.10.5 -j ACCEPT sudo iptables -A INPUT -p tcp --dport 22 -j DROP Save rules (Debian/Ubuntu) sudo iptables-save > /etc/iptables/rules.v4
On Windows (Advanced Firewall + PowerShell):
Block SMB inbound from all except backup servers New-NetFirewallRule -DisplayName "Block SMB from outside" -Direction Inbound -Protocol TCP -LocalPort 445 -Action Block -RemoteAddress Any Allow specific IP for backup New-NetFirewallRule -DisplayName "Allow SMB from backup server" -Direction Inbound -Protocol TCP -LocalPort 445 -RemoteAddress 192.168.100.10 -Action Allow Restrict RDP to specific security group New-NetFirewallRule -DisplayName "Restrict RDP to Admins" -Direction Inbound -Protocol TCP -LocalPort 3389 -Action Allow -RemoteUser "DOMAIN\RemoteDesktopUsers" Block WinRM from internet Set-Item WSMan:\localhost\Client\TrustedHosts -Value "" -Force Disable-PSRemoting -Force
API security for cloud workloads:
Use AWS WAF to block Medusa-related patterns (e.g., POST requests to /api/encrypt) aws wafv2 create-rule-group --name "BlockRansomwarePatterns" --scope REGIONAL --capacity 100 Add regex pattern to match "/api/encrypt" or ".medusa" in URI
4. Monitoring for Storm-1175 Specific Indicators (Sigma/YARA)
Storm-1175 uses tools like SystemBC, Cobalt Strike beacons, and custom PowerShell droppers. Deploy detection rules.
Step‑by‑step guide to deploy detection:
Linux – auditd rules for suspicious command lines:
Log all wget/curl downloads from non-standard sources auditctl -a always,exit -S execve -F path=/usr/bin/wget -F key=wget_download Add to /etc/audit/rules.d/ransomware.rules -w /bin/systemctl -p x -k medusa_persistence -w /usr/bin/vssadmin -p x -k shadow_deletion Monitor for Medusa-related process names ps aux | grep -iE '(medusa|encrypt|ransom|locker)' | mail -s "Alert: Storm-1175 suspect" [email protected]
Windows – PowerShell script to hunt IOCs:
Check for Medusa registry persistence
Get-ItemProperty -Path "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Run" | Select-Object | Where-Object {$_ -like "medusa"}
Search for known Medusa service names
Get-Service | Where-Object {$_.DisplayName -match "Medusa|WindowsUpdateMedusa"}
Use Sysmon (install first) to detect network connections to known C2 IPs
Create a list of Storm-1175 C2 IPs from threat intel
$badIps = @("185.130.5.253", "45.155.205.233") example placeholder
Get-NetTCPConnection | Where-Object {$_.RemoteAddress -in $badIps} | ForEach-Object { Write-Warning "C2 connection detected" }
- Rapid Incident Response & Recovery Without Paying Ransom
If encryption begins, immediate actions can limit damage.
Step‑by‑step guide (Windows/Linux):
On Windows (if ransomware active):
Kill ransomware process by highest CPU or disk write Get-Process | Sort-Object -Property CPU -Descending | Select-Object -First 5 | Stop-Process -Force Block outbound C2 traffic at host firewall New-NetFirewallRule -DisplayName "Block Medusa C2" -Direction Outbound -RemoteAddress 185.130.5.0/24 -Action Block Recover shadow copies before deletion attempt Run immediately, as Medusa deletes them vssadmin list shadows Mount a shadow copy as drive Z: mklink /d C:\ShadowCopy \?\GLOBALROOT\Device\HarddiskVolumeShadowCopy1\
On Linux (halt encryption):
Find and kill the encrypting process (high I/O, unknown binary)
iotop -b -n 1 | grep -E 'disk write.[0-9]+M' | awk '{print $1}' | xargs kill -9
Unmount network shares to prevent lateral encryption
umount /mnt/backup /mnt/nas
Use systemd to isolate the compromised container (if using Docker)
docker ps --filter "status=running" --format "{{.Names}}" | xargs -I {} docker kill {}
What Undercode Say:
- Patch windows are shrinking dramatically – Storm-1175 proves that organizations have less than 24 hours to patch internet-facing vulnerabilities after public disclosure. Automated patch management and virtual patching (WAF) are no longer optional.
- Defense-in-depth stops fast movers – Ransomware prevention isn’t just about antivirus. Network segmentation, application allowlisting, and rapid containment playbooks are the only reliable defenses against sub-24-hour intrusions.
- Visibility into N-day exploits is critical – Threat intelligence feeds that highlight actively exploited vulnerabilities must trigger immediate automated responses (e.g., blocking exploit patterns at the edge).
Prediction:
Storm-1175’s tactics will become the new baseline for ransomware groups. In the next 12 months, we expect to see AI-assisted vulnerability scanning that automatically matches public PoC exploits to exposed assets, reducing the attacker’s time-to-compromise from hours to minutes. Organizations that fail to adopt real-time vulnerability response and zero-trust network access (ZTNA) will face ransomware attacks with no time to react. The healthcare and education sectors, already targeted, will see a 200% increase in successful breaches unless regulatory bodies mandate sub-4-hour patching SLAs for critical CVEs.
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IT/Security Reporter URL:
Reported By: Mayura Kathiresh – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
