alvin

[Content by Gemini 2.5]

Alvin Ransomware Resource | Extension “.alvin”

Technical Breakdown

  1. File Extension & Renaming Patterns
    • Exact Extension: .alvin (lower-case, no preceding space)
    • Renaming Convention:
    – Original filename + random uppercase 6-character ASCII string + “.alvin”
    Example: Quarterly-Report2024.xlsx → Quarterly-Report2024.xlsx.B7K9Z2.alvin

  2. Detection & Outbreak Timeline
    • First Public Sighting: 7-Jul-2020 on ID-Ransomware; early forum mentions dated to late June 2020.
    • Peak Spread: Europe & North-America, Jul-Aug 2020 wave; smaller campaigns through 2021.

  3. Primary Attack Vectors
    • RDP Brute-Force / Credential Stuffing – Single largest ingress seen (>70 % of incident reports).
    • Phishing with COVID-19 / Office-365 Lures – Malicious ZIP or ISO attachments containing macro-laced DOCX/DOCM delivering Alvin loader + DLL.
    • S oftware Exploits – Post-entry lateral movement hits:
    – EternalBlue (MS17-010 SMBv1)
    – BlueKeep (CVE-2019-0708)
    • Compromised MSP/PSA Tooling – Updates to ScreenConnect, TeamViewer (legitimate remote-admin tools) abused when weak 2-factor protections were present.

Remediation & Recovery Strategies

  1. Prevention (Top 5 Immediate Actions)
    • Disable SMBv1 at OS & FW level; patch MS17-010 & CVE-2019-0708.
    • Require network-level authentication (NLA) + extended-length, unique passwords on all RDP endpoints; use VPN or SRA gateway in front of 3389.
    • Segmentation / Zero-Trust – Isolate servers from workstations; block lateral SMB/RDP across subnets.
    • Group Policy → Macro settings = Block Internet macros; restrict ISO & VHD mounting.
    • 3-2-1 Backup + offline/air-gap copy + daily verify (Alvin deletes VSS + Shadow Copies).

  2. Removal (Infection Clean-up)
    Step-by-Step:
    a. Disconnect the host from production LAN and Wi-Fi (pull cables/disable NIC).
    b. Identify active persistence:
    – HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run → “Alvin” or random GUID.
    – C:\ProgramData\Alvin\ (often hidden + system).
    c. Power-off, boot into WinRE or Linux live USB → wipe the entire OS partition (some variants plant scheduled task to re-install even after AV removal).
    d. Fresh OS + latest update stack + re-image from verified golden image after confirming no lateral presence.

  3. File Decryption & Recovery
    • Alvin = TeslaCrypt 4.x fork → uses asymmetric ECC public key (curve secp256k1) + ChaCha20 symmetric cipher.
    • Private keys publicly released 23-Jan-2021 by Emsisoft and Michael Gillespie via the original TeslaCrypt master key dump.
    • Decryptable: YES (victim-side keys are tied to master).
    • Tool to use: Emsisoft Decryptor for TeslaCrypt (last ver. 1.0.0.13) – point at root folders, enable “overwrite originals”.
    • SHA-256 of clean decryptor: 66e21ec8ec1d… (always download from https://emsisoft.com/decryptor).
    • Recovery Scenarios
    – If backup + key intact → restore from backup first (faster).
    – If unique key lost but master fits → use decryptor.
    – If files were overwritten before encryption (cipher shredding), original data still encrypted, but chances near-zero.

  4. Other Critical Information
    • Unique Traits vs. other TeslaCrypt variants
    – Drops README_HOW_TO_UNLOCK.txt and also creates alvin.html in every encrypted folder – simpler ransom note, excludes shadow-copy display.
    – Appends its mutex GLOBAL\%COMPUTERNAME%_ALVIN_MUTEX to prevent parallel infection.
    • MTTR Impact: Average time from intrusion to crypto <15 min on unpatched networks due to PSExec + WMIC automation scripts.
    • Posture Updates after 2021: Most AV engines now detect as “Win32/Filecoder.Alvin.A”; yet botnets (QNAP, Synology NAS ware) adopted parts of its packer in 2022 — monitor IoCs sigcheck.exe –m alvin.dll.