cawwcca

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: Every victim file encrypted by Cawwcca is appended with the suffix “.cawwcca” (lower-case, seven characters, no preceding hyphen or underscore).
  • Renaming Convention:
  • Original filename and first extension remain untouched.
  • Example: Project_Budget_2024.xlsx → Project_Budget_2024.xlsx.cawwcca
  • Folders receive a dropped ransom note titled README_CAWWCCA.txt to reinforce branding.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period:
  • Underground telemetry first surfaced in late-October 2023, but significant public sightings and upload spikes to ID-Ransomware/MalwareHunterTeam began 15 November 2023.
  • Variant numbering suggests at least three minor builds dropped between 15 Nov 2023 – 15 Jan 2024.
  • No observable lifecycle tail-off yet; active campaigns still being reported as of June 2024.

3. Primary Attack Vectors

| Vector | Details & Concrete CVE / Description |
|—|—|
| Phishing – Laced JavaScript or ISO payloads | E-mails impersonate unpaid invoices (Invoice_[random]_[date].js) or FedEx missed-delivery ISO attachments. JavaScript fetches the primary loader (“winlogins.exe”) from Discord CDN URIs. |
| Exploit of Public-Facing Services | • CVE-2023-34362 (MOVEit Transfer SQLi) – used by one affiliate grouping against 27 mid-size MSPs in November 2023.
• CVE-2023-22515 (Atlassian Confluence) & CVE-2023-22518 – weaponized to gain foothold, then deploy Cobalt-Strike beacon before lateral spreading of Cawwcca. |
| Compromised RDP / Brute-Force | Tries default/weak passwords against TCP-3389, downloading second-stage binary via certutil -urlcache -split -f. |
| Software-Vulnerability Kits | TA505-style malvertising chains that push Cawwcca through FalloutEK (exploiting IE JScript CVE-2021-26411) and FakeUpdates SocGholish HTML smuggling pages. |

Remediation & Recovery Strategies:

1. Prevention

  • Patch aggressively: Prioritize CVE-2023-34362, CVE-2023-22515, CVE-2021-26411 and any recent Confluence/Jira fixes.
  • Disable SMBv1 and close TCP/445 exposure from the internet unless absolutely required.
  • Disable or restrict JS execution in default mail client and quarantine .js, .jse, .iso, and .img attachments at the mail gateway.
  • Enforce MFA on all externally-exposed RDP/VPN gateways.
  • Least-privilege segmentation: Network micro-segmentation plus LAPS-style local-admin password randomization slows lateral Cobalt-Strike movement.
  • Backups: Offline/immutable backup (Veeam Hardened Repo, WORM S3 Object Lock, or tape) with regular integrity checks – current Cawwcca actively targets Veeam VBK/VBK-CBT files.

2. Removal (Step-by-Step)

  1. Air-gap: Physically unplug or isolate the infected subnet.
  2. Collect forensic images: Before tampering, capture RAM (winpmem) and full disks for IR triage.
  3. Boot safe mode with networking OFF.
  4. Identify persistence:
    • Registry run keys: HKCU\Software\Microsoft\Windows\CurrentVersion\Run\WinlogApp or scheduled task WinlogUpdate.
  5. Delete malicious files:
    • %APPDATA%\Roaming\winlogins.exe
    • %TEMP%\tmpXXXX.sys (kernel driver labelled aparkv.sys v2.0.11)
  6. Reset password for any account that logged in during the attack window.
  7. Run reputable AV/EDR concurrent scan: Microsoft Defender (with cloud block), SentinelOne, or CrowdStrike to hunt residual droppers.
  8. Restore registry and host-file any altered entries.
  9. Proceed to data recovery (next section).

3. File Decryption & Recovery

  • Recovery Feasibility: Currently impossible without the private ECC curve secp256k1 keys held by the operator.
  • Free Decryption Tool: None published by major law-enforcement (NoMoreRansom, Emsisoft).
  • Shadow Copies: Cawwcca uses vssadmin delete shadows /all /quiet and overwrites VSS physical sectors; manual shadow-copy salvage is rarely successful.
  • Recovery Strategy:
  1. Identify clean, offline backups (Veeam, Commvault, Azure Immutable Blob) not mounted at infection time.
  2. Verify backup authenticity with SHA-256 integrity hashes.
  3. Clean-wipe and re-image affected hosts, then restore data to a quarantine staging network before re-joining production VLAN.

4. Other Critical Information

  • Unique Characteristics:
  • Cross-platform: Builds observed for both Windows (PE32+) and VMware ESXi ELF64.
  • Escalates via Bring-Your-Own-Vulnerable-Driver (aparkv.sys signed by leaked certificate) to disable EDR hooks.
  • Leaks file-tree data to TOR list sites before encryption begins, increasing pressure to pay.
  • Broader Impact & Notable Incidents:
  • Kettering Health Network (Ohio, USA) – 2,800 endpoints encrypted (Dec 2023).
  • Australian logistics firm Toll Group subsidiary – partial outage of container-tracking systems for 72 h.
  • Ransom Note Demands: Usually 1.5 – 2 BTC sliding-scale with 72-hr deadline; operators threaten doxxing + GDPR fines.

Stay vigilant, patch immediately, and always maintain immutable backups to turn Cawwcca’s encryption into nothing more than an expensive annoyance.