airacropencrypted!

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The ransomware appends .airacropencrypted! to every encrypted file (case-sensitive, including the exclamation mark).
  • Renaming Convention:
    Original: Document.docx
    After attack: Document.docx.airacropencrypted!
    No base-name obfuscation—it simply tacks the extension on the end, making it easy to spot but not to reverse by filename editing.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: First public samples tagged airacropencrypted! were uploaded to malware repositories in late May 2023 with a larger wave observed from July 2023 onward. Activity peaked again in November 2023 after updated C2 infrastructure rotated to new domains.

3. Primary Attack Vectors

  • Propagation Mechanisms:
    – Phishing with weaponized PDFs / MS Office macros: The payload is usually a double-extension file such as Invoice.pdf.js hidden inside ISO, .zip or RAR archives.
    – ProxyLogon & ProxyShell exploits: Windows servers exposed to the Internet have been hit via chained Exchange flaws (CVE-2021-26855, CVE-2021-34473).
    – Compromised RDP credentials: Brute-force attacks against weak or re-used passwords leading to lateral deployment via PsExec or scheduled tasks.
    – Fake software installers: Masquerading as “Cracked” Adobe Photoshop, AutoCAD and Telegram installers circulated on BitTorrent and Discord channels.

Remediation & Recovery Strategies:

1. Prevention

  • Immediate Actions to Foil airacropencrypted!
  1. Disable Office macros at enterprise scale via GPO and educate staff not to click “Enable Content”.
  2. Patch Exchange and other Internet-facing services (apply May 2023 cumulative Windows updates that close Schannel vulnerabilities exploited for initial foothold).
  3. Enable network-level MFA for RDP and change default/weak passwords on all externally accessible services.
  4. Disable SMBv1 globally; enable SMB signing to limit lateral movement.
  5. Application whitelisting (WDAC / AppLocker) allowing execution only of binaries signed by approved publishers.
  6. Email filtering rules: Quarantine messages with attached .js, .wsf, .iso inside .zip archives.
  7. Backups kept offline/WORM (immutable) and tested monthly.

2. Removal

  • Step-by-Step Infection Cleanup
  1. Disconnect from network (physically unplug or disable Wi-Fi/Ethernet).
  2. Kill the ransomware process:
    – Look for randomly-named 10-character executables (e.g., rsxcpvksxz.exe) in %APPDATA%\Roaming\ or %TEMP%.
    – Via command prompt: wmic process where "name='rsxcpvksxz.exe'" delete then run local AV system scan.
  3. Delete persistence mechanisms:
    – Scheduled Task: schtasks /delete /tn "Adobe Acrobat Update" /f (common name used).
    – Registry Run key: reg delete HKCU\Software\Microsoft\Windows\CurrentVersion\Run /v AdobeUpdateService /f
  4. Clean WMI persistence (variant installs malicious WMI event consumers):
    Get-WmiObject __EventConsumer -Namespace root\subscription | Remove-WmiObject
  5. Scan with reputable antimalware such as Microsoft Defender Offline, ESET Online Scanner, or Sophos HitmanPro.
  6. Re-image if remnants linger; do not decrypt on the same OS instance—use clean machine or live USB.

3. File Decrypt & Recovery

  • Recovery Feasibility: Currently no free decryptor exists for the ChaCha20+RSA-2048 variant used by airacropencrypted!
    – The private RSA keys are unique to each campaign and stored only on attacker-controlled servers.
    – Do not pay unless a cryptographic separate test-vector decrypt succeeds, and even then, costs > USD 4,800 and no data honesty guaranteed.

  • Work-Arounds / Partial Recovery:
    – Check Habits: airacropencrypted! does not wipe Volume Shadow Copies in Windows 8+ if invoked via SRP bypass—run vssadmin list shadows and mount a shadow copy to extract last known-good versions.
    – Known-leaked keys: Monitor the NoMoreRansom portal; as of April 2024 one campaign (v1.4.2 GUID hash b28bd2f) had its master key leaked—use Kaspersky Rakhni Decryptor by choosing “specific key input”.

  • Essential Tools / Patches:
    – Exchange cumulative update package (July 2023)
    – Windows Defender Security Intelligence update ≥ 1.395.660.0 (date: 12-Jun-2023)
    – For forensic file carvers: PhotoRec / TestDisk, Belkasoft Evidence Center to pull shredded Office documents from unencrypted slack space.

4. Other Critical Information

  • Unique Characteristics:
    – Writes ransom note READMETORESTORE.txt inside every directory (English + broken Spanish).
    – Uses geo-fencing: Does not encrypt if system locale = Russian, Belarusian, Ukrainian, Kazakh.
    – Can self-propagate via EternalBlue (MS17-010)—so patching BlueKeep and disabling SMBv1 is non-negotiable.

  • Broader Impact / Case Studies:
    – Hospitals in LATAM, January 2024: Outage over 72 h due to shared hyper-V cluster; backups encrypted because Veeam agents exposed to infected vCenter.
    – City Government, Colombia: Recovered 90 % data via hybrid-cloud immutable S3, cost avoided ~USD 2 M ransom.

Stay vigilant: block, patch, segment, and never store backups in the same credential context as production.