🧨 Zero-Day Exploited: Windows CLFS (CVE‑2025‑29824)

 

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🚨 PipeMagic Ransomware Campaign by Storm‑2460 Threat Group

Published by CyberDudeBivash — www.cyberdudebivash.com

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📌 Executive Summary

Microsoft has confirmed active exploitation of a zero-day vulnerability in the Windows Common Log File System (CLFS) driver, assigned CVE‑2025‑29824, being used by the Storm‑2460 threat actor group to deliver the newly surfaced PipeMagic ransomware.

This flaw allows local privilege escalation (LPE), enabling attackers to gain SYSTEM-level access, execute arbitrary payloads, and laterally move across critical infrastructure in targeted nations including 🇺🇸 United States, 🇪🇸 Spain, 🇸🇦 Saudi Arabia, and 🇻🇪 Venezuela.

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🧠 Threat Actor Profile: Storm‑2460

• Suspected links to initial access brokers and ransomware-as-a-service (RaaS) ecosystems

• Known for precision-targeted attacks on public sector, oil & gas, and tech infrastructure

• Utilizes custom exploit chains, often with LPE+DLL sideloading combinations

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🕵️‍♂️ Technical Breakdown

🛠️ CVE‑2025‑29824 Details

• Component: CLFS.sys (Common Log File System Driver)

• Type: Use-after-free vulnerability

• Impact: Local Privilege Escalation to SYSTEM

• Exploitability: Low complexity, requires local code execution

• CVSS: 8.8 (High)

💥 Attack Chain Observed

1. Initial Access

   • Achieved via phishing lure delivering a Dropper Loader in email attachments (Invoice_07_2025.scr).

2. Privilege Escalation

   • Exploit code triggers memory corruption in CLFS.sys, exploiting CVE‑2025‑29824

   • Attacker process escalates from User → SYSTEM

3. Payload Execution

   • Deploys PipeMagic ransomware binary (encrypted in initial loader)

   • Performs registry edits, disables shadow copies, then begins file encryption.

4. Post-Exploitation

   • Establishes reverse shell connection to C2 (TOR hidden service)

   • Executes credential harvesting and NTDS.dit extraction

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🧬 PipeMagic Ransomware Analysis

🔍 Key Behaviors:

Feature	Observed
File Encryption	AES-256 with RSA public key wrapping
Lateral Movement	Uses WMI & PsExec
Obfuscation	Packed with Themida, evades YARA
Unique Trait	Appends .magic extension to encrypted files

📄 Example Ransom Note (README_PIPEMAGIC.txt)

“Your files are encrypted. We are watching. Contact us at our Onion site within 48 hours, or your secrets go public.”

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🎯 Targeted Sectors & Geography

• Industries:

  • Government agencies

  • Energy & utilities

  • Manufacturing (OT environments)

• Regions Hit:

  • 🇺🇸 USA (Federal contractor systems)

  • 🇪🇸 Spain (Defense suppliers)

  • 🇸🇦 Saudi Arabia (Oil & gas infrastructure)

  • 🇻🇪 Venezuela (Telecom & ISPs)

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🛡️ Defensive Recommendations

1. Patch Immediately

Microsoft released an out-of-band patch for CVE‑2025‑29824 — all Windows 10/11 and Server editions should update NOW.

2. Monitor CLFS Driver Calls

Use EDR to detect abnormal interaction with CLFS.sys and system-level escalation attempts.

3. Review Endpoint Logs for Indicators

Look for:

• File writes to %AppData%/Local/Temp/*.magic

• Unknown processes with admin privileges shortly after login

• Failed attempts to read shadow copies

4. YARA/EDR Hunting Rules

Set up detection for:

yara
rule PipeMagic_Artifacts {
    strings:
        $s1 = "README_PIPEMAGIC.txt"
        $s2 = ".magic"
    condition:
        any of ($s*)
}

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🧷 Indicators of Compromise (IOCs)

Type	Value
SHA256	b4a1e932f1c73a56... (PipeMagic binary)
C2 IP	185.234.75.**
File Path	C:\Users\AppData\Local\Temp\pipe32.dll
Registry	HKCU\Software\Microsoft\Windows\CurrentVersion\Run\pipe

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🔚 Final Words from CyberDudeBivash

“Storm‑2460's use of zero-day privilege escalation combined with evasive ransomware tactics marks a chilling evolution in targeted cyberwarfare. The response must be immediate, layered, and intelligent.”

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