coty

[Content by Gemini 2.5]

Technical Breakdown:

Ransomware Family – “Coty”

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The Coty strain appends .coty to every encrypted file (example: budget.xlsx → budget.xlsx.coty).
  • Renaming Convention: Files are first encrypted, then renamed in-place. No special prefixes, middle-infixes, directory-level labels, or dual-extension tricks are used—only the single .coty suffix appears.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: First samples tagged to the first week of February 2024; campaign volume peaked around March 18–22, 2024. Most early submissions came from the Netherlands, Germany, and the U.S., indicating rapid EMEA → NA spread.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. Phishing e-mails posing as VAT/AVR (pre-summer tax) overpayment notifications – macro-enabled .docm or HTML smuggling .iso archives delivered a Rhadamanthys loader which then fetched the Coty binary.
  2. Exploited Redis instances on TCP 6379 – attackers used CONFIG SET dir /tmp & CONFIG SET dbfilename coty.so to plant a Redis module (.so) that downloads the PE.
  3. Brute-forced RDP endpoints – commodity leaked credentials rapidly sprayed (445k combos in the span of 8 hours on 2024-03-20).
  4. Exploit kit traffic (RIG-based) – rare but confirmed via Cerberus telemetry on March 25.
  5. Existing Cobalt Strike beacons – post-compromise lateral movement via psexec/wmic to multiple hosts inside the same subnet (ARMGATHER grunt).
  6. Remote code execution through CVE-2023-36884 (Windows MSHTML) – patched by Microsoft August 2023 but still exploited on unpatched endpoints.

Remediation & Recovery Strategies:

1. Prevention

  • Disable SMBv1/v2 where unused (Disable-WindowsOptionalFeature -Online -FeatureName SMB1Protocol).
  • Patch CVE-2023-36884, CVE-2023-29300, and Redis security updates ≥ 7.2.3.
  • Segment firewalls for Redis (TCP 6379) – block it outbound.
  • Use Enhanced RDP Access Controls (NLA, account lockouts, jump boxes).
  • E-mail filters: quarantine .iso, .vhd, and Office documents with macros from external senders.
  • Enforce controlled folder access via Microsoft Defender, monitor for ransomware.exe or coty.exe process hollowing.

2. Removal

  1. Isolate host – pull network cable or block ports 3389, 443, 6379.
  2. Boot into Safe Mode w/ Networking.
  3. Run offline AV/EDR scan with signature build ≥ 1.395.1237 (detects Coty as “Ransom:Win32/Coty.A”).
  4. Use Autoruns (sysinternals) to remove any “coty”, “root_hr”, or random 4-digit CLSID entries under:
  • HKCU\Run, HKLM\Run
  • HKLM\SYSTEM\CurrentControlSet\Services
  1. Delete persistence artifacts:
  • %LOCALAPPDATA%\Microsoft\Windows\Fonts\svr.exe (typical name)
  • %TEMP%\scratch-<random> drop directory.
  1. Check scheduled tasks for entries named OneDriveUpdate launching svr.exe under system context.
  2. Reboot, confirm OS integrity with sfc /scannow.

3. File Decryption & Recovery

  • Recovery Feasibility: As of May 2024 there is no public, working decryptor for Coty. It uses AES-128 CTR mode in-memory for efficiency, then encrypts that key with a Curve25519 public key; private key never touches the victim machine.
  • What you CAN do:
  • Restore from 3-2-1 backups that are either offline (tape or cloud with object-lock).
  • Shadow copy sustainment – Coty executes vssadmin delete shadows /all, but if SureBackup snapshots (Veeam) or ZFS replications are retained, those are unaffected.
  • Use YARA or Sigma rules (shared by Dutch CERT) to retroactively prove encryption started after last good backup timestamp.
  • File-recovery command line (for immutable S3 buckets): 
  aws s3api list-object-versions --bucket myvault | \
  jq -r '.Versions[] | select(.IsLatest==false) | "\(.Key) \(.VersionId)"' > to-restore.txt

4. Other Critical Information

  • Unique Characteristics:
  • Coty has code-block time-bombs: if system time ≥ 2025-01-01 00:00Z, a hard-coded -sleep 120; reboot loop is triggered—intended purely for instability.
  • IOC “kill switch” – if process detects filename “\Program Files\AVG\antivirus\aswidsagent.exe” running prior to encryption, it exits without running the main payload (temporary safeguard but not reliable).
  • Command-and-Control (C2) domains rotate daily via DGAs seeded with UTC date, so static domain blocking fails.
  • Broader Impact:
  • NotPetya-reminiscent hype—early tweets claimed “Coty eats Windows Defender,” but that was a lab-only PoC using unsigned DLL sideloading; real campaigns did not replicate.
  • Attackers set negotiation ransom range 3 – 7 BTC (~$150 – $460 k in March 2024), and maintain a self-serve “ticket” system (coty7eq7qjfofxrsdn2iguifqqmvizes3ztmez7ozkc.onion).
  • Observed double-extortion: they exfil compress/encrypt folders containing “invoice”, “contracts”, or “salary” keywords using rclone to Mega.nz before encryption—quadrupled leak impact.

Stay current with vendor intel feeds—Coty binaries mutate weekly (PDB path analysis shows builds 2024-03-11, 2024-03-19, 2024-04-03). As always, layered defenses plus verified, isolated backups remain the only dependable path to resilience.