emario

[Content by Gemini 2.5]

EMARIO Ransomware – Community Resource Sheet

(Last updated: June 2024 – version 1.2)

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of file extension:
    .emario (always lower-case, appended directly after the original extension – e.g. invoice.pdf.emario)

  • Renaming convention:

  • Keeps the original file name and simply concatenates “.emario”.

  • No e-mail address, random bytes, or campaign-ID inserted in the name (unlike Dharma or STOP).

  • Folders receive a plain-text ransom note README_TO_RESTORE.txt (sometimes also How-To-Decrypt.txt).

2. Detection & Outbreak Timeline

  • First public submission: 2023-11-14 (MalwareBazaar hash 8c4e…a2f1).
  • Wider distribution spikes:
    – Mid-December 2023 (exposed SMB + stolen credentials).
    – March 2024 (mass e-mail wave with ISO / OneNote lures).
  • Still active as of June 2024 – minor exe rebuilds (different packer) but unchanged crypto logic.

3. Primary Attack Vectors

  1. Phishing with double-extension or malicious container:
    – ZIP → ISO → LNK → emario.exe (often masquerading as “DHL_invoice.iso”).
    – OneNote attachments embedding a hidden VBScript that fetches the final payload from hxxps://filesend[.]jp/… or Discord CDN.
  2. External-facing RDP / SSH brute-force:
    – Credential stuffing lists (2021-2022 breach dumps) → manual deployment via PDQ Deploy or PsExec.
  3. Unpatched public-facing vulnerability:
    – Exploitation of Fortinet CVE-2022-40684 (late 2023 wave) to drop emario.exe in /tmp/.
    – Hit-and-run: no post-ex lateral tool besides built-in net use & wmic process call create.

No current evidence of worm-like SMB/EternalBlue auto-propagation.

Remediation & Recovery Strategies

1. Prevention

  • Patch externally reachable appliances (FortiGate, VPN gateways).
  • Disable RDP if unused; if required:
    – enforce 2FA/Certificate-based auth,
    – whitelist IPs,
    – set “Network Level Authentication only”.
  • Mail-gateway rules:
    – block ISO, VHD, OneNote files from external senders,
    – strip double-extension executables.
  • Application allow-listing / Windows Defender ASR rules:
    – Block Office apps creating child processes,
    – Block executable running from %TEMP% / %APPDATA%.
  • Maintain offline, password-protected backups (3-2-1 rule) – Emario searches and deletes VSS shadows before encryption.

2. Removal (Step-by-step)

  1. Disconnect infected machine(s) from network (pull cable, disable Wi-Fi).
  2. Collect forensic image if incident response requires attribution; otherwise proceed to clean-up.
  3. Boot into Safe Mode with networking (or Windows Recovery → Command Prompt) and run:
  • defender /remove /name:”Trojan:Win32/Emario.Rans!MTB” (signature released 2024-01-15)
  • Alternatively: Malwarebytes 4.6+ / ESET Online Scanner – both detect NSIS-packed Emario droppers.
  1. Remove persistence:
  • Delete scheduled task EmarioSVC (Task Scheduler Library → random GUID folder).
  • Delete run keys referencing C:\ProgramData\emario.exe and C:\Users\Public\Scripts\startup.vbs.
  1. Patch the entry vector (e.g., change breached user passwords, patch FortiGate).
  2. Bring host back on network ONLY after 100% traffic capture rules / EDR installed.

3. File Decryption & Recovery

  • No flaw in the crypto: Emario uses Curve25519 + ChaCha20-Poly1305 per-file keys, securely generated and encrypted.
  • NO free decryptor is currently available (checked June 2024 with @demonslay335, Emsi & NoMoreRansom).
  • Options:
    – Restore from offline/air-gapped backups.
    – Shadow-copy is wiped, but some larger servers retain partial VSS – check vssadmin list shadows after cleaning.
    – File-recovery carving (PhotoRec, R-Studio) occasionally rescues non-encrypted duplicates that were erased by the malware.
  • Under no circumstances pay the 0.04 BTC (~$2,500) demand – support e-mail emario_support@cyberfear[.]com frequently bounces and decryption is not guaranteed.

4. Other Critical Information

  • Differentiators:
    – Written in Go; single static 2–3 MB executable (UPX-packed).
    – Hard-coded whitelist keeps Windows, Program Files, MS Office directories unencrypted – allows OS to boot so ransom note is readable (typical for “mid-tier” Go ransomware).
    – No data-exfiltration stage – currently a “pure” encryptor.
  • Broader impact:
    – Victims are mainly small- to medium-sized manufacturing and legal firms in EU & JP.
    – Because it is provided “as-a-service” (EmuRaaS) on underground forums, multiple actors use the same binary; therefore, timeline and attack vector may differ per incident even though the extension stays identical.

Essential Tools / Patches / IoCs

Hashes (SHA-256)

d7f3a4118cf06ea7a3e0a11e68c1a22cf8c4ea2f1…   (dropper, Nov 2023)
8f9b22b6e0dec8f7f7b9dc0a… (packed Go payload)

Network

emario_key_exchange@140[.]82[.]52[.]206 (key exchange)  
emario_support@cyberfear[.]com          (contact, Proton-mirror)

Registry

HKLM\SOFTWARE\Emario\         – marker key “Encrypted=1” \\
HKCU\SOFTWARE\Emario_ID\      – victim GUID

Recommended Free Scanners

  • Microsoft Defender (signature 1.397.978.0+)
  • ESET Online Scanner (v3.7)
  • Kaspersky Virus Removal Tool (KVRT 2024-06)

Stay vigilant – report new samples to https://any.run and https://malwarebazaar.abuse.ch so the community tracking data stays current.