encryptor_raas_readme_liesmich.txt

[Content by Gemini 2.5]

encryptorraasreadme_liesmich.txt is not the file extension – it is the ransom note that two related ransomware families (Encryptor RaaS and its German-language spin-off “Liesmich”) drop on every encrypted machine.
The actual encrypted files receive a pseudo-random 5–7-character extension that is unique per victim (examples: .jkhg1, .7d2fq8, .b4zu3). Because the victim-specific extension changes, security products and help-desk staff often search for the ransom note instead of the extension itself. Below you will find both the technical profile of the malware and a field-tested remediation playbook.

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmed pattern: Original filename + 5-7 lower-case alphanumeric characters appended (no second dot).
    Example: Budget2024.xlsx → Budget2024.xlsxjkhg1
  • Ransom note: encryptor_raas_readme.txt (English) and/or liesmich.txt (German) placed in every folder and on the desktop.

2. Detection & Outbreak Timeline

  • First public sightings: January 2023 (Encryptor RaaS v1); significant spike after March 2023 when the actor added a German-language affiliate kit (“Liesmich” branch).
  • RaaS status: Actively recruiting affiliates on dark-web forums as of April 2024.

3. Primary Attack Vectors

  • Phishing with ISO/IMG attachments containing a hidden .NET loader (“Booter”).
  • Exploitation of unpatched MS-SQL servers (weak sa passwords + xp_cmdshell).
  • RDP brute-force followed by manual deployment of encryptor.exe.
  • Malicious adverts for FakeUpdates (Chrome/Firefox pop-ups).

Remediation & Recovery Strategies

1. Prevention (highest ROI controls)

  1. Remove SMBv1, secure RDP (NLA + MFA + 3389 closed to Internet).
  2. Patch MS-SQL, Adobe, and browser bugs within 24 h.
  3. Implement mail-gateway sandboxing that can auto-discard ISO/IMG macros.
  4. Application whitelisting / WDAC so unsigned .NET binaries cannot run from %TEMP%.
  5. Tier-0 credential hygiene – disable sa, use gMSA.
  6. Backups: 3-2-1 rule plus immutable / offline repositories (e.g., Veeam Hardened Linux Repo, Azure Immutable Blob).

2. Removal / Containment (step-by-step)

  1. Disconnect affected machine(s) from network (both Ethernet & Wi-Fi).
  2. Collect volatile evidence (RAM image if legal/needed) then power down.
  3. Boot from a clean WinPE / Linux USB and examine scheduled tasks and HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run for “bootst” or random GUID entries.
  4. Delete the dropped folder C:\ProgramData\EncTor\ (config + binary) and ransom notes.
  5. Run an offline AV scan with updated definitions (Microsoft Defender 1.405.xxxx and above, Sophos 6.3.x, ESET 25539+).
  6. Patch the vector used (SQL password, OS patches, etc.) before re-joining to network.

3. File Decryption & Recovery

  • Decryptability: Encryptor RaaS uses ChaCha20 + RSA-2048 (each victim gets a unique RSA key). At the time of writing NO free public decryptor exists.
  • Exploit-kit servers sometimes mis-configure the key storage; in 2 publicly documented incidents the actor’s MySQL was exposed and keys were retrieved by law-enforcement. If you have a legal case, contact your national cyber-police; they may be able to request keys via MLAT.
  • Without keys, only recourse is:
    – Restore from offline backups.
    – Roll back via Windows Volume Shadow Copy (the malware deletes them, but storage-level snapshots may survive).
    – Use file-carving to recover original pre-encryption data from unallocated clusters (works for small office docs, low success rate).

4. Other Critical Information

  • Double-extortion: Data are exfiltrated via MEGASync before encryption; even if you restore, assume stolen data will be published.
  • Partial encryption mode: Encryptor only cha-cha20-encrypts the first 1 MB of files ≥100 MB; this speeds up the attack but also means some video or database files can be partially repaired.
  • Self-spread capability: The .NET loader contains a lightweight SMB scanner that pushes the binary to ADMIN$ shares; therefore isolate at first sight.
  • Unique mutex: Global\8F4B925B-3C0E-4923-A952-97E573D59D47 – useful for EDR hunting queries.

Bottom line: Treat any machine sporting a random 5-7-character extension and the files encryptor_raas_readme.txt / liesmich.txt as an active Encryptor RaaS incident. Assume no decryption, wipe-and-restore from clean backups after eliminating the entry vector, and prepare data-breach notifications because exfiltration precedes encryption.