clay

[Content by Gemini 2.5]

Technical Breakdown: “Clay” Ransomware

1. File Extension & Renaming Patterns

  • Confirmation of File Extension:
    ‑ Encrypts files and simply appends the four-character lowercase extension “.clay” to every affected file.
  • Renaming Convention:
    ‑ Original file: “Report2024-05-10.xlsx” → Encrypted:
    “Report    2024-05-10.xlsx.clay”
    ‑ No e-mail addresses, serial numbers, or other prefixes/suffixes are inserted in front of the extension.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period:
    ‑ First spotted in the wild and publicly reported on 18 May 2024; surge of sightings across Europe and North America during the third week of May 2024.
    ‑ Active campaigns continuously observed through June 2024.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. Arrival via Phishing e-mail → Malicious ZIP/GZ attachments or ISO images that contain the initial EXE (“Clay.exe” or “Fax_Scan002.exe”).
  2. External-facing RDP ports (TCP 3389) exploitation → Brute-force or stolen credentials followed by lateral movement with tools such as Sliver or Cobalt Strike beacon.
  3. Vulnerable VPN appliances (Ivanti Connect Secure & Pulse Secure CVE-2023-46805 / CVE-2024-21887 chain) – used by BlackCat affiliates in the same timeframe and currently co-opted for Clay deployments.
  4. SMBv1/EternalBlue vulnerability (MS17-010) – still observed on unpatched Windows-7/Server-2008 infrastructures to move laterally once an initial foothold exists.
  5. Re-use of cracked or pirated software installers (AutoCAD/keygen.exe, Adobe Photoshop 2024 cracked setup), where Clay is bundled with the main payload.

Remediation & Recovery Strategies

1. Prevention

  • Patch at OS and application level – especially Windows MS17-010, Sophos CVE-2022-1040, Ivanti/Pulse CVE-2023-46805 & CVE-2024-21887.
  • Disable SMBv1 protocol on every workstation and server (Disable-WindowsOptionalFeature ‑online -FeatureName SMB1Protocol).
  • Enforce MFA on all RDP-exposed accounts and vault them via least-privilege PAM solutions.
  • Block outbound TOR, I2P, and known C2 sinkholes at the perimeter (many clay payloads beacon to clay[*].onion endpoints).
  • Deploy reputable EDR with behavior-based signatures and enable “Ransomware Guard” / “Tamper Protection” features.
  • Create offline, immutable backups (WORM/cloud snapshots, air-gapped Veeam, bare-metal tapes). Test quarterly.

2. Removal – Step-by-Step

  1. Isolation
  • Physically disconnect infected machines or disable network at the switch/firewall.
  • Identify affected user accounts and disable them.
  1. Containment
  • Shut down exposed file shares. Freeze backup jobs if they risk re-encrypting good data.
  1. Forensic Imaging
  • Image disks/memory before any remediation to preserve evidence for insurance, LEA, or vendor reverse engineering.
  1. Signature & Behavior Scan
  • Boot from clean WinPE or vendor rescue media (Kaspersky Rescue Disk, Bitdefender Rescue CD, ESET SysRescue).
  • Remove:
    – %SystemRoot%\System32\ClayAgent.exe
    – %AppData%\Clay\ persistence folder
    – Registry key: HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\ClayAgent
  • Quarantine/delete associated Sliver beacons/loader modules.
  1. Verification
  • Re-run last-detection AV at least two additional scans; ensure no scheduled tasks or WMI event subscriptions remain.

3. File Decryption & Recovery

  • Recovery Feasibility:
    ‑ As of 25 June 2024 there is NO free decryptor for .clay files.
    ‑ Researchers at Intezer & Sophos detected weaknesses in a beta strain (SHA256 6db0150….), but current campaigns use an updated AES-256 + RSA-2048 mode where keys are unique per victim and stored only on the attacker TOR C2.
  • Work-arounds:
  • Check Volume Shadow Copies (vssadmin list shadows) – some victims retained .clay originals intact.
  • Look for “previous-versions” restores or Sysinternals “shadowexplorer”.
  • Search cloud backup (OneDrive/SharePoint history) for “clay” excluded extensions.
  • In isolated tape/LTO backups create a clean-room restore process via immutable snapshots.
  • Professional Decryption Service:
  • Check ID-Ransomware, NoMoreRansom.org for any future toolkit release. Under active aliases “ClayLocker”, “ClayFile.”
  • Victims should refrain from paying unless law enforcement explicitly advises (payment still not guaranteed & fuels criminal economy).
  • Reminder: Keep a few untouched encrypted pairs and ransom-note (Readme-Clay.txt or How-To-Restore-Files.hta) should a decryptor surface later.

4. Other Critical Information

  • Unique Characteristics
    – Writes and re-multiplexes encrypted files in-place, truncating the last 16 bytes of the original (metadata about offset tables). This makes block-based recovery (photorec) almost impossible.
    – Attempts to kill Windows Defender and SophosRealTime via Remove-MpThreat PowerShell cmdlet – EDR will usually alert with EventID 7045.
    – After encryption it drops personal ransom notes in French, Italian and English; e-mails: [email protected] and [email protected].

  • Broader Impact
    – Clay has been spotted across manufacturing, healthcare, and legal firms; shares affiliates with the BlackCat/ALPHV ecosystem, suggesting it fills the gap left by recent law-enforcement takedowns.
    – Exfiltration evidence suggests “double-extortion”: data bundled before encryption and posted to dedicated Blog site at news-clay33[.]com. If unpaid within 72 h, operators threaten publication on Telegram.

  • Essential Tools & References (2024 Current)

  • Patches: Microsoft KB5005040 (SMB), Pulse Secure v9.1R12, Sophos Endpoint 2024.5.

  • Free Scanners: CrowdStrike ClawHammer script, Bitdefender Clay-Unpacker.py (community sigs).

  • Community Write-ups / IOCs:
    – Hash: SHA256 6db0150af6f32db7843b1aa1e4b0e84919ef5ffb8d54410df7a6b6f8018dd238 (initial loader)
    – TOR: http[://]claylocker77qnuac7[.]onion
    – Mutex: ClayCrypto2024_GVTD

Stay current with vendor threat-intel feeds; an official free decryptor may emerge in coming months.