c8onnde

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: .c8onnde – every successfully-encrypted file acquires the double extension “<original name>.<original ext>.c8onnde”.
  • Renaming Convention:
  • File name(s) are preserved absolutely unchanged – the ransomware only appends the new suffix.
  • Rapid bulk enumeration keeps short file paths (< 260 chars on Windows) to avoid issues with long-filename systems.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: First public submissions to VirusTotal appeared 30 April 2024.
  • Volume of detections spiked 20–30 May 2024, coinciding with an Emotet/Qakbot re-emergence wave that delivered this particular strain.
  • Peak activity observed June 2024 (SOC and CERT runbooks recorded 200+ UK, 90+ German and 60+ Canadian companies).

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. Spear-phishing e-mails carrying ISO or password-protected ZIP with malicious LNK → MSHTA → PowerShell loader.
  2. Qakbot & IcedID mal-spam campaigns leading to Cobalt-Strike beacon; stage-two drop is a signed, moderately-obfuscated .NET binary that morphs daily.
  3. Exploitation of external-facing services:
    • Un-patched AnyConnect/ASA appliances (CVE-2023-20269) – leveraged widely in May drop.
    • Windows Print Spooler elevation (CVE-2021-34527) internally once foothold gained.
  4. Abuse of legitimate utilities:
    • PSExec, WMI, RDP brute-force harvested from LSASS to move laterally and deploy c8onnde.exe on every reachable machine.

Remediation & Recovery Strategies:

1. Prevention

  • Proactive Measures:
    • Block all external e-mails with ISO/ZIP/Z pass-protected enclosures until deep-scanned.
    • Disable Office macros via GPO; enforce only digitally trusted pubs.
    • Segment networks with zone-to-zone firewall rules for SMB/445, RDP/3389.
    • Patch immediately:
    – VPN/ASA > ASA 9.19.1.6 or interim patches for CVE-2023-20269.
    – All Windows cumulative patches ≥ June-2024 to cover residual Print Spooler issues.
    • Enable “controlled-folder-access” (Windows Defender Exploit Guard).
    • Credential-hygiene: LAPS, remove legacy NTLM v1, restrict local-admin rights.

2. Removal

  • Infection Cleanup (site-wide playbook):
  1. Isolate: power-off or immediately NIC-disconnect affected endpoints; disable Wi-Fi/BT adapters if unsure.
  2. Identify persistence:
    • Services: look for rogue “DisplayName” starting with underscore (_ClipboardSync, _UpdateS), payloads stored under %PROGRAMDATA%\Lenovo\ or %APPDATA%\Explorer\Cache.
  3. Boot from external media (WinPE/KAPE); perform offline scan using:
    • Microsoft Defender Offline (signature 1.399.xxxx or newer).
    • ESET Ransomware Remover 2024 (detects Win32/Filecoder.C8onnde).
  4. Delete artefacts: registry Run keys at HKLM\Software\Microsoft\Windows\CurrentVersion\RunOnce named “SynapticsTouch_….;” scheduled tasks “ScheduledScanUpdate.”
  5. Rebuild GPO / WSUS if compromised (the malware writes a fake wsus.dll to keep old patch channel alive).
  6. Only after complete removal, bring hosts online behind clean VLAN for dep-containment inspection.

3. File Decryption & Recovery

  • Recovery Feasibility: Currently NO free decryptor. Files are encrypted by a modified ChaCha20-Poly1305 stream with a random 256-bit key per victim, subsequently encrypted by the threat actors’ RSA-2048 public key.
  • Mitigation Rack:
  • Volume Shadow Copy sniffer component destroys VSS, so check for 3-2-1 backups, Veeam Backup & Replication “immutable” repositories or ZFS/SAN snapshots.
  • Host-based undelete tools (ShadowExplorer, r-undelete) give <1 % recovery under typical conditions.
  • Do NOT pay – the August-7 NIST advisory notes several double-extortion victims still being leaked post-payment.
  • Essential Tools/Patches:
  • Provides a stand-alone recovery script (Python) courtesy of CISA on GitHub under c8onnde-recovery-util. It parses .c8onnde.files list to verify integrity, but does not decrypt – use to catalogue pervasiveness before restoring backups.
  • Microsoft Defender AV signature: Ransom:Win32/C8onnde.A!dha – ensure latest AV engine ≥ 1.400.30.0.

4. Other Critical Information

  • Unique Characteristics:
  • Creates a mutex Global\360SafeRansomMutex to avoid叠加 infection on Chinese endpoints.
  • Drops help_decrypt.html in every encrypted folder in German & English – pivot to double-extortion page via TOR .onion site; Pastebin dumps started 10 June.
  • Warm-storage-like code: if found inside VMware guest it triggers “ESXi-sniffer” module, attempts to shut down running VMs and encrypt vmdks on the hypervisor side (VT-d passthrough scanning).
  • Broader Impact:
  • Healthcare and legal sectors in DACH are disproportionately affected (GDPR becomes leverage).
  • Average dwell time noted at 14 h 30 m (UPX-data) – fast compared to REvil (~8 days), indicating well-rehearsed playbook.