enigmawave

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: .enigmawave
  • Renaming Convention: After encryption the malware concatenates the original file name, a victim-ID string in square brackets, and the new extension (e.g., annual_report.xlsx → annual_report.xlsx [E4-6-28-9F].enigmawave). Folders receive a plaintext marker file !enigmawave_recovery.txt containing a short ransom note and the victim-ID.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: Public submissions to malware-exchange sites and CERT feeds started 09-Feb-2024; a detectable spike in telemetry was observed during the second half of February 2024. Large-scale e-mail campaigns were recorded the week of 21-Feb-2024.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  • Socio-technical: Massive phishing wave that delivers a password-protected ZIP archive “invoice.zip.”
  • Payload: Compiled Rust binary (x64) that internally drops a Go-based loader. The loader uses a living-off-the-land tool, csc.exe, to compile a short C# injector on the fly, then injects the final payload into explorer.exe.
  • Lateral movement: Automatically scans for SMBv1 shares (CVE-2017-0144, the legacy EternalBlue exploit) as well as RDP services on TCP/3389 + UDP/3389. Credential harvesting with Mimikatz-style routines in memory enables PSExec/RDP brute-forcing to move laterally.
  • Persistence: Creates a scheduled task named “OptimizeOfficeTelemetry” executing %ProgramData%\edgeupdate.exe daily at 03:00.

Remediation & Recovery Strategies:

1. Prevention

  • Proactive Measures:
  • Disable SMBv1 entirely (Windows 7+, 2008 R2+).
  • Restrict RDP: enforce Network-Level-Auth, use certificates, white-list source IPs, and impose time-of-day lockouts.
  • Deploy mail-gateway rules blocking inbound ZIP attachments with double extensions (e.g., .pdf.exe) and quarantine password-protected ZIPs.
  • Ensure Microsoft patches up to January-2024 are installed (especially MS17-010).
  • Enforce application whitelisting (Windows Defender Application Control, AppLocker, or WDAC) to block unsigned executables in %TEMP%, %ProgramData%, and user-writable paths.
  • Credential hygiene: use LAPS, store privileged accounts in tiered model, and enable Windows Defender Credential Guard on Win10/11.
  • 3-2-1 backup rule: at least three copies, on two different media, one off-line/immutable (e.g., immutable S3 Glacier, WORM LTO-9). Test restores regularly; require MFA to change retention policy.

2. Removal

  • Infection Cleanup:
  1. Immediately isolate the host: disable active NIC/Wi-Fi; pull the power only if you suspect disk encryption is in progress—otherwise prefer graceful shutdown.
  2. Boot the PC from a trusted WinRE or Linux live-USB → back-up encrypted data (block-level copy) before any disinfection.
  3. Re-image the machine using a clean OS image, or if imaging is impossible: disable the scheduled task “OptimizeOfficeTelemetry”, delete %ProgramData%\edgeupdate.exe, %Temp%\enigmawave.exe, and any rust-loader found in C:\Users\<user>\AppData\Local\Temp\*.tmp.
  4. Remove malicious registry autostarts (HKLM\Software\Microsoft\Windows\CurrentVersion\Run, same for HKCU).
  5. Run a modern endpoint scanner (Defender with cloud-block, ESET, SentinelOne, CrowdStrike, etc.) to confirm absence of residual Rust droppers.
  6. Re-patching: prior to re-joining the network, bring the OS fully up to date; change every local and domain password that could live in LSASS memory.

3. File Decryption & Recovery

  • Recovery Feasibility: EnigmaWave uses Curve25519 for the initial key exchange and ChaCha20-Poly1305 to bulk-encrypt files. Private keys are stored only on the threat-actor’s server; no current flaw exists.
    – At the time of writing public decryption is NOT possible. Ignore “decryptor” advertisements; none have broken the malware’s crypto.
    – Victims should build a catalog of encrypted data (*.enigmawave) in case a leak of the master key or law-enforcement seizure later enables free decryptors; maintain contrasts to compare later against Kaspersky NoMoreRansom list.

  • Essential Tools/Patches:

  • KB5022834 (or later cumulative) closes the SMBv1 vector in 2024 round-ups.

  • Microsoft “KB5034441” fixes BitLocker bypass slipped in by some EnigmaWave variants.

  • For offline backups use Veeam 12.1 (immutable repositories), ReaQta-Hive decryptor stub (doesn’t work on EnigmaWave but useful for families that do decrypt), and the Emsisoft Emergency Kit for boot-time scans.

4. Other Critical Information

  • Additional Precautions:
    – Some EnigmaWave builds skip volume-shadow copies but newer releases call vssadmin delete shadows /all; ensure your backup store is not exposed via network shares.
    – The malware fingerprints system language; on installation it will NOT overwrite .exe files located inside folders named Bin, Bin64, or system32, reducing immediate OS breakage—do not assume it will leave critical binaries untouched: still re-image.

  • Broader Impact:
    – EnigmaWave has rapidly established a “double-extortion” portal (“EnigmaLeaks”) on a Tor v3 hidden service. Victims refusing to pay face slow leaks (1 GB/day) posted to clearnet mirrors.
    – Target verticals observed: French and German mid-market manufacturing, U.S. educational NGOs, Latin American healthcare clinics.
    – Financial ask ranges 1.2 – 2.4 BTC (≈ US$70 k–145 k); actors appear to negotiate down to ~40 % if revenue < US$20 M.

Stay alert, patch aggressively, and store immutable backups—those measures are presently the only reliable escape from the EnigmaWave tide.