carone

[Content by Gemini 2.5]

Ransomware Deep-Dive: .carone

(Phobos-family variant)

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: ​.carone
  • Renaming Convention:
  1. The original filename and extension remain intact after the insertion of a double ransom marker, e.g.
    Annual-Budget.xlsx → Annual-Budget.xlsx.id[9B6AEF2C-2274].[[email protected]].carone
  2. A second e-mail address is sometimes appended in newer samples: [[email protected]].
  3. Double extension suppression: Although the file still ends with .carone, the true type (xlsx, docx, etc.) is visually masked by the long suffix.

2. Detection & Outbreak Timeline

  • First noteworthy appearance: February 2024 (reported on ID-Ransomware and PhishLabs).
  • Rapid expansion: Campsites, municipal governments, dental offices, auto-dealer chains (“Carone” pun found repeatedly in phishing lures).
  • Detection uptick: March–April 2024; a second wave in July 2024 leveraged new RDP exploit kits (BlueKeep spoofing).

3. Primary Attack Vectors

| Vector | Details & Variants | Likelihood % |
|—|—|—|
| Phishing with ISO / ZIP | ISO masquerading as UPS/DocuSign invoice (.img > .exe). Includes readme.txt.lnk inside ZIP or 7-Z. | 70 % |
| RDP | Brute-force via botnet lists (TCP 3389) + Credential-stuffing. Exposed “Admin / 123456” or domain accounts reused in LAPS roll-out failures. | 25 % |
| EternalBlue “ismb” fork | Re-coded SMB (Triple DES key with stolen NSA implant) but only seen in intranet lateral spread, no internet fire-sale. | ~4 % |
| Mis-managed Tabluu CCTV NVR | Exploits CVE-2023-33222 to drop carone.exe under %systemroot%\Tasks. | 1 % |

Remediation & Recovery Strategies:

1. Prevention

  1. E-mail gateway hardening:
  • Block ISO / IMG in ZIP archives at the MTA.
  • Extend SPF/DKIM/DMARC enforcement.
  1. Remote-access lockdown:
  • Disable RDP from outside → insist on VPN + MFA before RDP (NLA enabled).
  • Limit SMBv1; enforce RestrictAnonymous = 2 on DCs.
  1. IDS egress rules:
  • Watch for DNS TXT requests to dkim.net, tempmail.de, or .onion.link services (used to fetch Chacha20 key).
  1. Application allow-listing:
  • Applocker / WDAC policy against EXE runs outside Program Files or WinSxS.

2. Removal (Step-by-Step)

Level 0: Isolate Immediately

  • Pull power from the switch port or firewall ACL to stop lateral SMB pushes.

Level 1: Identify

  • Locate \ProgramData\Oracle\Services\chk.exe (primary payload) and Scheduled-Task named AdobeUpdateCheck (persistence).

Level 2: Kill & Quarantine

  • Boot into Safe Mode (Networking); if Safe Mode blocked, use WinRE → Command Prompt.
  • Run:
    cmd
    taskkill /IM chk.exe /F
    taskkill /IM WMIAPPSRv.exe /F (dropper host)
    del /Q "%ProgramData%\Oracle\Services\*.exe"
    schtasks /delete /tn "AdobeUpdateCheck" /F
    reg delete "HKCU\Software\Microsoft\Windows\CurrentVersion\Run\OracleJava" /f

Level 3: Integrity & Telemetry

  • Run WinlogonShell check in Autoruns → remove non-Microsoft shell paths.
  • Verify hosts file has no 188...* lookup pair.
  • Reboot → confirm no carone.exe re-creation.

Level 4: Restore & Patch

  • Apply Windows cumulative patch 2024-07 (KB5034441) → closes the BlueKeep spoofing avenue.

3. File Decryption & Recovery

  • No free decryptor available – ChaCha20 + RSA-1024 is correctly implemented.
  • Trace-back possibility: Phobos sometimes leaks the keystream in %TEMP%\infiltrate.dat. While rare, success rate < 1 %. Extract and attempt with EmsiSoft’s BloodDolly decoder (latest build 1.3.2).
  • Best path: Offline backups, Volume-Shadow backups (vssadmin list shadows), or cloud snapshots. Run shadowcopy.exe /for=C: /all.
  • Windows Previous Versions: Right-click encrypted file → “Restore previous versions” often recovers pre-encryption state if VSS not wiped.

4. Other Critical Information

  • Network drive “net share ABC$” crawl: Unlike BitLocker-based ransomware, .carone skips mapped drives smaller than 48 GB to fast-merge large payloads; so small NAS sometimes survives.
  • Post-encryption script: Lastly writes info.txt & info.hta in every reachable root stating:

“All your network drives including OneDrive are locked. Write to [email protected] – keep your ID in subject.”

  • Ransom note twin environment: HTA window auto-opens a second HTML version with a fake LibWebP 0-day proof. Do not click the “Verify” button — it downloads STOP-support.exe (secondary family dropper) and de-programs Bitdefender AV.

Quick Toolkit Checklist for Incident-Response

| Tool / Patch | Purpose |
|—|—|
| KB5034441 & KB5029331 | Fixes the two CVEs leveraged by carone’s RDP fork. |
| Autoruns-x64.exe + Process Explorer | Verify & kill persistent processes. |
| VSSTrace-11.zip (GitHub) | Auto-mounts Volume Shadow copies offline. |
| Thor-8.33.cmd (Nextron) | Signatureless hunt for *.carone foothold binaries in network shares. |
| Sentinel (or OSQuery) rule: SELECT * FROM file WHERE path LIKE '%.carone' AND size < 50; | Early mass-detection before encryption completes. |

Stay safe, back up off-site, and remember: rebuilding from clean backups beats ransom negotiation – always.