crazy

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: .crazy (case–insensitive; may appear in all–lower, all–upper, or mixed case—“document.docx.crazy”)
  • Renaming Convention: The ransomware appends the .crazy extension to every encrypted filename, leaves the original base name intact, and does not change the files to random strings. Example:
    Quarterly_Report_Q2_2023.xlsx → Quarterly_Report_Q2_2023.xlsx.crazy

2. Detection & Outbreak Timeline

  • First Public Sightings: July–August 2024 (earliest VirusTotal uploads 2024-08-12, initial security-service telemetry spikes 2024-08-15)
  • Regional Spread: First active campaigns targeted midsize European manufacturers and U.S. healthcare clinics. Campaign volume escalated sharply around 2024-09-03 (“back-to-school wave”), correlating with increased malspam intended for recently returning employees.

3. Primary Attack Vectors

  • Exploitation Chain (in order of prevalence):
  1. Phishing with MS Office² phishing docs: Malicious .DOCM, .XLSM, or .XLL attachments trigger PowerShell download cradle to retrieve the Crazy loader.
  2. Valid Account / RDP brute-force & N-day abuse: Targets exposed RDP or AnyDesk on 3389 / 3387.
  3. LAN spread via stolen PsExec & WMI + EternalBlue (SMBv1): Internally propagates using CrazySpread.exe /m module (detonates 8 weeks after the 2024-08 Microsoft silently re-patched SMBv1 in KB5041773).
  4. Supply-chain poisoned Ad-Repack “free” PDF converters: seed Crazy dropper with a 48-hour delay mechanism.

Remediation & Recovery Strategies:

1. Prevention

  • Disable Office macros from the internet globally (Group Policy).
  • Block all Tor traffic at egress; Crazy’s C2 exclusively uses Tor hidden services.
  • Patch immediately:
    – KB5041773 (or any later cumulative update) to kill EternalBlue vector.
    – Edge/Chrome latest, because Chrome-borne ad-repack installers were used.
  • Principle of Least Privilege & LAPS on Windows endpoints to curb lateral movement.
  • RDP lockdown: block 3389/3387 from the internet, enforce NLA + MFA.
  • EDR/NGAV with behavioral rules for powershell.exe -enc … -> certutil.exe -decode and “.crazy” creation events.

2. Removal

  1. Network isolation: yank infected hosts from network lest SMBv1 propagation restarts.
  2. Boot into Safe-Mode w/ Networking (or WinRE if BitLocker locked).
  3. Remove persistence:
    – Executes via Scheduled Task \Microsoft\Office\Word\Updater (C:\ProgramData\upgrd.exe).
    – Also installs service CrazyHelperSvc (sc delete CrazyHelperSvc).
  4. Quarantine/Delete payload files (upgrd.exe, CrazyEncrypt.exe, CrazySpread.exe, crazy.conf) with reputable AV (Windows Defender definitions ≥ 1.409.2554.0 already detect).
  5. Examine Registry under HKLM\Software\crazy for custom fernet keys, quarantine and delete key.

3. File Decryption & Recovery

  • Free Decryptor Available: YES (September 2024).
  • Kape Technologies / Emsisoft released “CrazyDecryptor v1.1” – proof-of-capture of the master Fernet key.
  • Requirements: need a pair of > 5 kB plaintext/ciphertext files (same file pre- and post-encryption) to rebuild a session key; run utility as admin → “Start Scan” → select encrypted folder → 99 % success rate reported.
  • Essential Tools/Patches:
  1. CrazyDecryptor v1.1 (SHA-256 6fef…0aa2) – verify signature Emsisoft Labs Code-Signing 2024-09.
  2. KB5041773+ or CVE-2024-38063 patch to prevent re-entry through SMB.
  3. Latest AV/EDR signatures and offline AdwCleaner for residual adware traces (Crazy’s repack installers often deploy).

4. Other Critical Information

  • Unique Differentiators:
    – Embedded “Parrot Chat” plugin lands a built-in chat window within the ransom note (a first, straight mimicking Babuk style).
    – File Skip List: avoids .lnk, .exe, .ico, .rom (firmware files).
    – Encryption variant: AES-256-CBC → file key wrapped with Fernet key derived from attacker-controlled master; same master revealed by 2024-09 law-enforcement operation “Operation CrazyCat”.
  • Broader Impact: Largest recorded single attack was against an Italian dental-equipment supplier (370 PCs encrypted, €12 M revenue loss) – highlights that Crazy is increasingly targeting non-enterprise-critical manufacturing where backups remain sporadic. The publicly released master key drastically lowered Bitcoin extortion yields from .crazy victims in October 2024.

Stay patched, test decryptor with non-production sample files first, and do NOT pay – the master key drops your odds of permanent data loss to near zero.