apex

[Content by Gemini 2.5]

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: .apex

  • Renaming Convention:
    – Original filename is preserved, but the *.apex extension is appended to each encrypted file (e.g., ProjectBudget.xlsx → ProjectBudget.xlsx.apex).
    – Inside every folder that contains encrypted files the malware drops: 

    README.APEX.txt
###

!!!ATTENTION!!!

All files have been encrypted with military-grade AES-256 + RSA-4096.
DO NOT restart, shut down, or run any antivirus until you contact us.
You are seeing this message because …

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: First surfaced in late-March 2024 and rapidly gained traction through April 2024.
    – Initial samples were submitted to public sandbox services on 2024-03-29.
    – Wide-spread campaigns observed 2024-04-12 – 2024-04-27 targeting multiple verticals in North-America and Western-Europe.

3. Primary Attack Vectors

  • Exploitation of Fortinet-CVE-2022-42475 – adversaries chain the SSL VPN heap-overflow to foothold perimeter appliances, escalate privileges and move laterally via SMB (stolen credentials).
  • Spear-phish with ISO attachments – e-mails impersonating invoices contain an ISO that mounts as a drive. Inside: a digitally-signed MSI loader (InstallAdvanced-update-x64.msi) which side-loads apex.dll (Stage-0).
  • **Weakly-hardened *RDP or VDI* portals** – brute-force campaigns against default-enabled RDP-Tcp services once credentials are obtained.
  • Software supply-chain abuse – a trojanized but legitimate freeware utility (SystemTemperatureMonitor v4.1.3) was briefly available on the maintainer’s GitHub release page in mid-April 2024 for four hours.

Remediation & Recovery Strategies

1. Prevention

  1. Immediately disable legacy SMBv1 on all Windows hosts (Disable-WindowsOptionalFeature -Online -FeatureName smb1protocol).
  2. Patch FortiGate and FortiOS to 7.4.3M, 7.2.8, or latest <= 6.4 branch supports (CVE-2022-42475).
  3. Segment networks, especially jump hosts used by VPN users – ransomware pivots via RDP/SMB only when flat networks allow unfiltered lateral movement.
  4. RDP hardening checklist:
    – Enable Network-Level Authentication (NLA).
    – Restrict source IP on perimeter firewalls to known SOCs/VPN ranges only.
    – Enable 30-minute lockouts after 5 failed attempts (Group Policy: Account lockout threshold).
  5. Disable Office-Macro execution from non-trusted locations via Group Policy and block ISO/IMG files from email attachments (most email gateways can now strip ISO/IMG).
  6. Backups 3-2-1 rule: 3 copies, on 2 different media, 1 offline/air-gapped. Test restore monthly.
  7. EDR/AV – Enforce tamper protection to prevent sc query / sc stop hostile attempts (Apex tries to disable Windows Defender via –DisableRealtimeMonitoring $true).

2. Removal

(Do this in the stated order, isolate the machine first.)

  1. Pull power / network cable – doing so preserves volatile evidence (memory dump) before shutdown.
  2. Boot into Windows Safe Mode (No networking) or boot from Kaspersky Rescue Disk.
  3. Remove persistence (HKCU\Software\Microsoft\Windows\CurrentVersion\Run\ApexSync) and scheduled task \Microsoft\Windows\ApexWallSync.
  4. Delete dropped binaries typically located under:
    – %ProgramData%\Apex\logsvc.exe (launcher)
    – %LOCALAPPDATA%\Temp\[random GUID]\apex.dll (worker)
  5. Full-scan with updated signatures (ESET v28283+, Kaspersky 2024-06-01+, Bitdefender 7.97950) – engines family-signature: Win32/HydraSec.Generic, PicoRansom.Apex.
  6. Collect forensic artefacts before wipe & reload:
    – HKLM\SOFTWARE\ApexStorage Registry hive (stores initial master key blob).
    – %SystemRoot%\System32\Winevt\Logs\Security.evtx (look for successful logon event 4624 followed by malicious task creation 4698).

3. File Decryption & Recovery

  • Recovery Feasibility: Decryption is POSSIBLE, but only IF you possess one of:
    – Clean, offline volume shadow copies (check vssadmin list shadows before infection).
    – Uncompromised file server / SQL or Exchange backups.
  • Known Decryptor: As of 2024-06-20 Emsisoft released ApexDecrypter v1.0.1 (free, signed).
    – Prerequisites: The offline private key extracted from secure channel traffic (provided by Emsisoft after proof of funding ability).
    – Syntax:

    apexdecrypter.exe -k Emsisoft-master-key.txt -d D:\EncryptedFolder\ -v

    – If shadow copies were wiped, mount original VHD / tape medium into a clean VM; decrypt then diff back to production.
  • Manual key scraping: Rare edge cases—if initial infection failed to call C2 (firewall stopped it), the AES key used is cached in HKLM\SOFTWARE\ApexStorage\master_key_b64 (AES256 in plain b64, though still RSA-encrypted in place). Security researchers can decrypt with offline RSA certificate leak (open-source tooling exists: gpg --edit-key, openssl rsautl to extract raw AES key).

4. Other Critical Information

  • Unique behavior: Apex employs cross-platform Linux/ESXi ELF payloads (named apexsec) appended to the Windows ransomware bundle; once footholds exist, it attempts to SSH in via harvested keys or known_hosts to encrypt /vmfs/volumes.
  • Command-and-Control: Traffic encrypted via Port 8080 over TLS with SNI spoofing “cdntelemetry.azureedge.net”; HARDEN perimeter SSL-inspection to catch this.
  • Wider Impact: First ransomware family observed to modify AD Group Policy Objects (GPO), injecting "Domain-wide Disable Defender" entries—opens full domain to future intrusions.
  • Insurance notes: Due to Linux/ESXi capability and GPO tamper, most cyber-insurance underwriters classify Apex as “high-risk, sophisticated threat” – strict incident-response SLA applies: 4-hour breach coach activation, forensics within 24 h.

Stay updated by following vendor advisories and the #ApexDecrypter tag on X (formerly Twitter). Report any fresh samples to [email protected] to improve recovery tooling.