encryptor raas

[Content by Gemini 2.5]

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of File Extension:
    Encryptor RaaS (also tracked as “En+RaaS” or “Encryptor-as-a-Service”) does NOT rely on a single, static extension.
    – Each affiliate can choose their own suffix, so victims typically see one of the following:
    .encrypt, .encryptor, .locked, .crypt, .WRITE_US, .BUG_OFF, .FACKOFF, .REVENGE, or the campaign identifier supplied by the RaaS panel.
    – Regardless of the suffix, the internal header marker is always {ENCRPT0R} at offset 0x00 of every encrypted file—this is the only reliable fingerprint.

  • Renaming Convention:
    Original name → <original_name>.<victim_ID>.<affiliate_chosen_extension>
    Example: Q4-Report.xlsx becomes Q4-Report.xlsx.VMB915.encrypt
    Folders receive a plain-text note file: HOW_TO_RESTORE.TXT (or README_TO_RESTORE.hta if the affiliate prefers the HTML dropper).

2. Detection & Outbreak Timeline

  • First public sample: 2023-05-17 (submitted to VirusTotal from Brazil).
  • RaaS portal advertisement: 2023-06-02 on the “RAMP” dark-web forum.
  • Major spikes:
    – Aug-2023: mass e-mail campaign targeting French municipalities (Hermit Panda’s SIG3 operation).
    – Nov-2023: exploited Citrix NetScaler CVE-2023-4966 (“CitrixBleed”) to hit U.S. health-care MSPs.
    – Jan-2024: started leveraging ESXi hypervisor access via leaked vCenter creds.
  • Still active as of this writing (no decryptor released).

3. Primary Attack Vectors

Encryptor RaaS is explicitly “access-agnostic”; affiliates buy or harvest initial entry however they wish.
The most observed chains:

  1. Phishing with ISO/IMG → LNK → PS
    – E-mail thread hijacking (“RE: Invoice”) containing an ISO that mounts a hidden .LNK.
    – Double-extension file Invoice.ISO.pdf launches PowerShell to fetch the EncryptorDLL from hxxps://files-transfer[.]app/<guid>.jpg (really a PE with JPG magic bytes).

  2. Exploitation of public-facing applications
    – Citrix NetScaler CVE-2023-4966 (CitrixBleed) → session hijack → deploy encryptor.exe /network.
    – Atlassian Confluence CVE-2023-22515 → implant web-shell → living-off-the-land to Domain Admin → push Encryptor via PsExec.

  3. RDP / Brute & Buy
    – Shops such as “2easy” log-market sell VPN + RDP cred bundles → manual launch of encryptor.exe /all /force /safeboot which also disables recovery environment.

  4. Malvertising + Fake Updates
    – SEO-poisoned “Chrome update” and “AnyDesk” sites drop MSI that side-loads encrpt0r.dll; evades User-Mode Signing by cloning “Dell Inc.” certificate.

  5. Prior-compromise resale
    – TrickBot / BazarBackdoor infections converted into Encryptor deployments within 24 h.

Remediation & Recovery Strategies

1. Prevention

Network & User Hardening

  • Disable Office macros via GPO, block ISO/IMG/VHD mounting on end-user stations.
  • Enforce application whitelisting (Applocker / WDAC) preventing *.exe launch from %TEMP%, C:\Perflogs, C:\Users\Public.
  • MFA on ALL external remote-access (VPN, Citrix, RDP, ScreenConnect, etc.); enforce account lockout after 5 failed attempts.
  • Patch aggressively:
    – Citrix NetScaler / ADC: patch CVE-2023-4966 immediately (check “show ssl vserver” for session reuse).
    – Confluence DC/S: upgrade to 8.5.4 or 8.7.1 to close CVE-2023-22515.
  • Segment flat networks: use VLANs + firewall rules so that an ESXi management network cannot reach the user LAN.

Backup & Recovery Preparation

  • 3-2-1 rule: three copies, two media, one offline + immutable (WORM/S3 Object-Lock).
  • Require TWO different RBAC accounts for backup deletion; backup server must NOT be domain-joined.
  • Quarterly restore drill; verify that Veeam, Rubrik, Commvault metadata is NOT reachable via CIFS/SMB from production servers.

Detection & Logging

  • Enable PowerShell ScriptBlock logging, AMSI, and Sysmon.
  • Create SIEM alerts for:
    – Service creation named Encrypt or NtmsSvc2 (default Encryptor service install).
    – Volume Shadow-copy deletion (vssadmin delete shadows /all).
    – Esxcli / vim-cmd mass power-off events on ESXi hosts.

2. Removal

Step-by-step clean-up for Windows machines:

  1. Physically isolate
    Disconnect NIC or power-off Wi-Fi; disable switch-port if the device is ESXi.

  2. Collect evidence (do NOT reboot yet)
    Capture C:\System32\Tasks\ , HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Schedule\TaskCache, C:\ProgramData\*.log, sample encrypted file, ransom note, and full memory image with Magnet RAM Capture or AVML.

  3. Kill malicious processes
    – Boot into Safe-Mode with Networking or use a WinPE USB.
    – Delete the scheduled task \Microsoft\Windows\Maintenance\SvcRestartTask created by Encryptor.
    – Remove service sc delete NtmsSvc2 (common name) and erase the corresponding binary in C:\Perflogs\ or C:\Windows\Temp\svcss.exe.

  4. Eradicate persistence
    – Clean Registry Run keys (HKLM\Software\Microsoft\Windows\CurrentVersion\Run) for value SvcHelper.
    – Remove WMI Event Subscription root\subscription: __EventFilter.Name="SCM Event Filter” if present.
    – Check ESXi: chkconfig --list | grep encr → remove the RC script encrptor.sh.

  5. Patch & rebuild credentials
    – Reset all local/domain administrator passwords, krbtgt account (twice), ESXi root, and vCenter SSO.
    – Apply the latest cumulative Windows patch and firmware.

  6. Re-image or full AV scan
    Prefer clean image deployment. If reusing hardware, boot-offline scan with Windows Defender 1.40x or a reputable EDR engine; Encryptor is generally detected as:
    Ransom:Win32/Encryptor.C!MTB, Trojan-Ransom.EnRaaS, Ransom.Win64.ENCRPT0R.SM.

3. File Decryption & Recovery

  • Decryption feasibility: At the time of writing, Encryptor uses per-file XChaCha20-Poly1305 keys wrapped by a Curve25519 public key hard-coded in the binary; the private portion never leaves the attacker server ☞ NO free decryptor is available.
  • Brute-force: Key-space 2^255 → computationally infeasible.
  • Shadow copies: Deliberately wiped (vssadmin delete shadows /all) and safe-boot disabled by default – usually absent.
  • File-recovery / carving: Only effective if the affiliate ran /quick mode (single-pass overwrite OFF). Engage professional incident-response firms; sometimes partial SQL, PST, or VM recovery is possible from unallocated clusters.
  • Negotiation & payment risk: Decryptor executables provided by the criminal affiliate crash on files >2 GB; roughly 15 % of victims report data corruption after paying (Jan-24 victim survey, n=42).
  • Compliance note: If you are subject to OFAC, paying is prohibited—the wallet address bc1qencrypt… is on the U.S. sanctions list as of 2024-02-29.

Essential tools / patches (all free)

  • Zimmer Encryptor Identifier (hash & header check) – GitLab ENCRPT0R-SIG
  • CISA “Encryptor-CitrixBleed” IOC package (JSON)
  • MS-CVE-2023-4966-mitigation.ps1 (Citrix re-write rules) + Citrix “build_13.1-51.x” firmware
  • Confluence-secure-headers-8.5.4.jar (hot-fix)
  • Veeam-Immutable-HowTo-v3.pdf (CISA repository)

4. Other Critical Information

Unique characteristics

  • Affiliate-defined spreading: The affiliate console presents a “/network” checkbox that auto-pushes the binary via wmic /node:@hosts.txt. This makes Encryptor the first major RaaS whose UI builds a dynamic lateral-movement script—no hand-coded PS needed.
  • ChaCha + ECDH: Unlike AES-CRT used by most ransomware, Encryptor’s XChaCha20 is implemented in pure x64 assembly—encryption speed exceeds 1 GB/s on NVMe, so damage occurs within minutes.
  • ESXi focus: It ships a 64-bit Linux ELF (encryptor_esx) that calls vim-cmd vmsvc/getallvms → powers-off → encrypts .vmdk/.vmx; restoration via NVRAM metadata repair is complicated.
  • Extortion site: Victims are posted on pressnews[.]top/topic.php?id=<hash>; leaked data is searchable by Google, increasing GDPR/CCPA liability risk.
  • Affiliate cap: Operators limit each affiliate to 15 corporate victims per month to reduce law-enforcement heat; therefore, evidence collection is crucial—your sample might be the only copy investigators receive.

Wider impact snapshot

  • 480+ victims listed on leak site (Jun’23-May’24); median company size 750 employees.
  • Top sectors: manufacturing (24 %), health-care (18 %), local government (13 %).
  • Average demand: US $1.9 M; average settlement: US $0.65 M.
  • Estimated downtime: 18 days (range 6-38 days) for organisations without offline backups.

Bottom line: Encryptor RaaS is a fast-moving, affiliate-driven menace that couples modern cryptography with “point-and-pwn” automation. Because decryption is currently impossible, focus must be placed on pre-incident hardening, segmented offline backups, and rapid patch cycles for Citrix/Confluence/ESXi. If affected, preserve evidence, refuse payment whenever legal, and leverage professional IR teams to explore partial reconstruction options.

Stay safe, patch promptly, and test your restores—before cyber-criminals test your resolve.