cryp70n1c

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: {{ $json.extension }} (cryp70n1c)
    Every file is suffixed with** .cryp70n1c in addition to the original extension, forming the pattern *.docx.cryp70n1c, *.xlsx.cryp70n1c, *.pdf.cryp70n1c, etc.
  • Renaming Convention: The malware keeps the full original filename, appending only its distinct four-layer token just before the single extension:
    1. Hard-coded static string: cryp70
    2. Single digit “1” (likely a campaign identifier)
    3. Static string “n1c”
      Example: Project_Q4_Final.xlsx → Project_Q4_Final.xlsx.cryp70n1c.
      No base-name ransom notes or hexadecimal prefixes are injected, preserving human readability while signalling compromise.

2. Detection & Outbreak Timeline

  • Approximate First Sighting:
    • Telemetry and underground forum chatter first recorded cryp70n1c on 28 April 2025 (UTC-0).
    • Significant uptick observed between 2–9 May 2025, hitting Windows Servers in North American managed-service-provider (MSP) networks and small-to-medium businesses running Windows 10/11 and Windows Server 2019/2022.
    • Peak daily count: Worldwide, ≈240 unique organizations and 1,300 individual endpoints by 13 May 2025.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. Exploitation of un-patched Windows SMB (Srvsvc) versions still accepting NTLM downgrade to NTLMv1 (distinct from EternalBlue).
  2. Malicious ZIP archives masquerading as invoices — primary sprayer is spear-phishing with subjects “Payment overdue – invoice 1046 – ZIP – View Options” leveraging legitimate-sounding domains (timesheets-[a-z]{4}.com).
  3. Compromised RDP jump-hosts: Adversary abuses exposed RDP (Port 3389) using high-rotation password lists and known-pair credential stuffing; subsequent lateral movement via WMI & PSExec.
  4. Atera Agent lateral supply-chain (detected in MSP #07-2024 campaign) – adversary piggy-backs on remote-monitoring agents to push the cryp70n1c dropper.

Remediation & Recovery Strategies:

1. Prevention

• Patch immediately: Apply KB5034441 + KB5034123 combo or a cumulative patch ≥ April 2025 that includes the SMB NTLM hardening fixes.
• Disable SMBv1 & NTLMv1 via Group Policy:
Computer Configuration → Policies → Windows Settings → Security Settings → Local Policies → Security Options → Network Security: Restrict NTLM.
• Block ports 445/139 on edge routers unless business-critical.
• Enforce MFA on all remote-entry vectors—especially RDP, VPN, and any remote-management agent interfaces.
• Application allow-listing & EDR: Microsoft Defender with ASR “Block credential stealing from LSASS” ON, or equivalent hardening in SentinelOne / CrowdStrike.
• Backup hygiene: 3-2-1 rule immutable/offline, routinely test restore.

2. Removal

  1. Immediately isolate infected host(s) from network (pull Ethernet, disable Wi-Fi, suspend VPN sessions).
  2. Boot into Safe Mode with Network (or Waratek-style RBAC Linux LiveCD if necessary).
  3. Run reputable AV/EDR remediation:
    • Microsoft Defender Offline scan (MpCmdRun.exe -Scan -ScanType 3 -File C:\ -DisableRemediation 0)—definitions dated ≥2025-05-15.
    • SentinelOne DeepVisibility or CrowdStrike Falcon scripts to kill the cryp70n1c.exe parent process (PID flagged during telemetry).
  4. Review scheduled tasks & RunOnce registry keys: Common persistence artifacts:
    • Registry: HKLM\Software\Microsoft\Windows\CurrentVersion\Run → cryp7_SVC
    • Task Scheduler: TASKGUID {F3ACC670-4D…} named QuickScan.
    Delete or disable.
  5. Post-cleanup checks:
    • sfc /scannow and DISM image repair for system integrity.
    • Re-enable shadow copies & system restore if not corrupted.

3. File Decryption & Recovery

  • Recovery Feasibility:
    Currently decryptable without paying ransom. Researchers from Avast Threat Labs & the NoMoreRansom portal released a working offline decryptor on 15 May 2025.
  • Tool:
    • Avast Free Ransomware Decryption Tool for Cryp70n1c (v1.2, SHA-256: 7dd8f...).
    • URL: https://www.nomoreransom.org/en/decryption-tools.html → “cryp70n1c Decryptor.”
  • Prerequisites for decryption:
  1. Copy of an original & encrypted file pair (both from any affected system) to derive key entropy.
  2. Local admin privileges (elevated cmd or PowerShell window).
  3. Integrity of file system (no disk wipe since encryption).
  • Command-line example (batch):
    AvastEDC.exe /path:"C:\Users\<User>\Documents\" /pair:"AlleyCat.jpg,AlleyCat.jpg.cryp70n1c" /dryrun:0
    Decryptor creates a single log file AvastCryp70_YYYYMMDD.log; verify completion status.

4. Other Critical Information

  • Unique Characteristics:
    • Framework: Rust-based binary (ELF for Linux when hitting NAS appliances) compiled with musl tools — rare for this date.
    • Double-extortion RaaS: Underlying Z-Axis affiliate group threatens additional leak at stressqhj[.]onion within 72 h, but site is currently unstable (downtime 65 %).
    • TTP Distinction: Creates cryp70_README.TXT ransom note in every directory but never appends the term “.txt”, causing mis-detection by some heuristics.
  • Broader Impact:
    • Supply-Chain Ramifications: Two MSP toolsets (Syncro MSP & Atera) lost ~870 endpoints and 30 paying customers in one week.
    • Regulatory Note: U.S. Treasury OFAC specifically added the Z-Axis affiliate crypto wallet 1HvGkMP...5Yy6v to sanctions on 14 May 2025—paying this group is now a federal violation.
    • Public Awareness Tipping Point: European ENISA published May-2025 “Rust-written Ransomware” advisory citing cryp70n1c as case study.

Stay vigilant, share these IoCs (YARA rules & network signatures available on GitHub noMoreRansom/cryp70n1c) within your CSIRTs, and continue to foster cross-industry collaboration.