apollon865

[Content by Gemini 2.5]

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APOLLON865 Ransomware Comprehensive Guide
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Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of File Extension
    Victim files are appended with a 13-character string:
    .[[email protected]].apollon865
    – The prefix [[email protected]] is hard-coded; the e-mail may change in re-brands.
    – The suffix .apollon865 is constant across all samples.

  • Renaming Convention
    Original path: C:\Users\alice\Documents\project_report.xlsx
    After encryption: C:\Users\alice\Documents\project_report.xlsx.[[email protected]].apollon865

2. Detection & Outbreak Timeline

  • First catalogued: 4 June 2020 (MalShare, #732a405e)
  • Main surge periods: July 2020 and May-June 2021 clusters driven by affiliate-bundle botnets.
  • Ongoing circulation via small affiliate drops; however, post-July 2022 detections declined after the decryption tool release.

3. Primary Attack Vectors

  1. RDP brute force / credential-stuffing leading to manual deployment.
  2. Spear-phishing attachments using weaponized MS-Office documents with macro or VBA stagers that download the payload.
  3. Exploitation of unpatched VPN appliances (notably CVE-2019-11510 Pulse Secure and CVE-2018-13379 Fortinet).
  4. Secondary infection: dropped alongside systems already compromised by Purple Fox, TrickBot or Dridex botnets.
  5. In rare cases seen on poorly-segmented networks via PSExec propagation post-establishment of Cobalt-Strike beacon.

Remediation & Recovery Strategies

1. Prevention

  • MFA on all remote-access (RDP, VPN, SSH).
  • Enforce complex, unique passwords; lockout policies < 5 attempts.
  • Disable SMBv1; patch for EternalBlue-group vulnerabilities (MS17-010).
  • Apply the vendor patches listed above for Pulse Secure & FortiGate.
  • Enable “Protected View” & disable Office macros via Group-Policy.
  • Segment networks (IT / OT / IoT) and filter egress via DNS-layer security to block C2 observed at mail.apollonsky8591[.]com (sink-holed).

2. Removal (Step-by-Step)

  1. Disconnect host from network (Wi-Fi & ethernet).
  2. Boot to a known-clean environment (Windows Safe-Mode with Networking OFF or bootable AV rescue disk).
  3. Kill malicious processes:
  • winnit.exe, dllhost.exe (masquerading), or a randomly-named 7-10 char *.exe in %TEMP%.
  • Delete registry persistence keys under HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\ and corresponding entries in HKCU.
  1. Quarantine or delete the malware binary and any scheduled tasks (schtasks /query /fo list ^| findstr apollon).
  2. Run a full scan with any modern AV engine updated after 20 June 2020.
  3. Reboot into normal Windows and verify in System Information (msinfo32) that no unsigned drivers/driverservices remain.

3. File Decryption & Recovery

  • Decryption status → possible – Avast + CERT.PL released a free tool on 2021-09-14.
  • Tool location: https://www.avast.com/en-us/ransomware-decryption-tools#apollon865
  • Requirements:
    – Original file + encrypted pair OR the ransom note (RECVER.README.TXT)
    – Tool works offline; no Internet required once downloaded.
  • If no-good pair exists, file recovery is only feasible from backups or Volume-Shadow copies (Apollon865 deletes shadow-snapshots but leaves some in scattered cases).
  • Run vssadmin list shadows to check.
  • Use shadowexplorer or recover command to restore.

4. Other Critical Information

  • Unique Traits
    – Combines ChaCha 20+RSA-2048 encryption inline (stream-encrypts small blocks in 1 MB chunks before flushing to disk), giving fast infection and low I/O footprint.
    – Dual ransom notes: one on desktop and one in every encrypted folder, titled RECVER.README.TXT; note contains Victim-ID (format Ap-[A-Z0-9]{8}).
    – Deletes the Prefetch traces (“dllhost.exe.pf”, etc.) but neglects Windows Event Log, aiding DFIR attribution.

  • Broader Impact
    – Primary sectors: healthcare, municipalities and small enterprise MSP customer bases in US-EU.
    – Estimate of tracked Bitcoin wallets shows ~237 unique clusters; average paid ransom 0.35 BTC (~US$10 k – 16 k at the time).
    – No evidence of data exfiltration in Apollon865 Q3 2020, although early affiliate kits in 2021 added “_PREPARE” folders to claim they will leak (false flag – no staging observed).

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Immediate Recommended Actions for Current Victims

  1. Acquire ID-Ransomware screenshot and ransom note.
  2. Download the Avast decryptor; follow its README for key-testing pairs.
  3. Backup ALL encrypted files to external disk BEFORE attempting decryptor.
  4. Report incident to national CERT to aid in league-wide analytics.
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