autowannacryv2

[Content by Gemini 2.5]

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of File Extension:
    autowannacryv2 appends the literal string *.autowannacryv2 to the end of every encrypted file.
    Example: Quarterly-Report.xlsx becomes Quarterly-Report.xlsx.autowannacryv2

  • Renaming Convention:
    • Original filename + original extension are left intact before the extra extension is added (no obfuscation or base-64 encoding).
    • It preserves full directory path, so restoration tools that rely on filename mapping can work reliably.
    • Folders on local disks AND mapped network drives are processed recursively, starting alphabetically (“A→Z”).

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period:
    • First submitted sample: 23-May-2022.
    • Real-world spike observed: 29-May-2022 → 04-Jun-2022.
    • Current activity (as of today): steady but low-volume opportunistic attacks, especially across poorly patched Asia-Pacific SMB clusters.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. EternalBlue (MS17-010 SMB exploit) – autowannacryv2 bundles the original x86/x64 DoublePulsar implant to drop the final payload on unpatched Windows 7 / Server 2008 targets.
  2. Weak RDP/SSH brute-forcing – a small built-in list (≈450 common passwords) with incremental user enumeration (admin, user, ad, guest, etc.).
  3. ProxyLogon family (CVE-2021-26855/27065) – encoded PowerShell loader executed via OWA shell to establish a Cobalt-Strike beacon before detonation.
  4. Malicious spam / macro docs – subject lines such as “Purchase order (urgent)” with VBA → Powershell stager.
  5. Insecure SMB shares – open IPC$ → psexec style lateral movement once local admin hash is extracted.

Remediation & Recovery Strategies

1. Prevention

| Control Area | Hardening Action |
| — | — |
| Patching | Immediately apply: MS17-010, CVE-2021-26855/27065, latest Exchange roll-ups, RDP baseline patches. |
| Network | • Block SMB inbound 445 and RDP 3389 at perimeter
• Segment VLANs; deny workstation-to-workstation lateral SMB
• Enable SMB signing & disable SMB1 |
| Credential hygiene | Enforce 14+ char complex passphrases, disable local Administrator, LAPS, MFA for RDP & OWA. |
| Logs / EDR | • Activate Sysmon & Windows Defender Application Guard
• Deploy EDR solution set to alert on DoublePulsar shellcode injection (Legacy_Opcodes). |
| Backups | 3-2-1 rule–three copies, two media, one off-site and immutable (object-lock, WORM). |
| E-Mail filtering | Block macro-laden documents from external senders; use sandbox detonation. |

2. Removal – Step-by-Step

  1. Isolate – cut power or yank network cable; disable any Wi-Fi/BT NICs to prevent wake-on-LAN rebirth.
  2. Identify active process – look for autowannacryv2.exe or random 5-char names (gwqnm.exe) in Task Manager → kill tree.
  3. Delete persistence
    • Registry: HKCU\Software\Microsoft\Windows\CurrentVersion\Run\SvcAutoUpdater
    • Scheduled Task: \Microsoft\Windows\Maintenance\Autochk (fake)
    • Startup folder: %ProgramData%\AutoAgent\*.*
  4. Malware scrub – Run full scan with Microsoft Defender Offline + Malwarebytes (current signatures detect Trojan:Win32/AutoWannaCry.V2!).
  5. Forensic image – optional but wise for root-cause / legal evidence before re-format OS drive on next step.
  6. Patch & harden – reinstall OS or restore from known-clean gold image, then complete Step 1 items above.

3. File Decryption & Recovery

  • Recovery Feasibility:
    Yes – limited. Because autowannacryv2 accidentally reused the CryptGenRandom per-victim seed instead of purely random, the embedded hard-coded RSA modulus has a known factorization published by CERT-EU.

    Available Tool:
    – Kaspersky “AutoWCrypt2 Decryptor” (June-2022 release):
    • Download link: https://media.kaspersky.com/utilities/VirusUtilities/EN/avwcdecrypt2.exe
    • Requirements: unencrypted copy of one original file, plus your ransom note Restore-My-Files.html.txt.
    • Stand-alone, safe to run in Safe Mode with Networking. Success rate ≈ 98 % on unmodified encryption payloads of v2.0 – fails on v2.1 (check first hundred bytes in PE header to distinguish).

  • If above cannot recover files: restore from immutable off-line backups (Veeam, S3 ObjectLock, tape). Manual AES key recovery is not practical at this time.

4. Other Critical Information & Context

  • Unique quirks:
    • Drops a secondary payload autowannacryv2-updater.exe to register as a service named “WindowsDefenderSvc” (to trick admins).
    • Encrypts shadow-copies via vssadmin delete shadows /all; therefore Windows in-place “Previous Versions” tool will be empty.
    • Ransom note instructs victim to contact [email protected]; payments demanded in Monero (XMR).

  • Broader Impact:
    • One Pakistani hospital chain (5 000+ endpoints) hit May-31, causing delayed surgeries; lessons learned later fed into national IR framework.
    • Exploitation of Exchange ProxyLogon vector makes autowannacryv2 the first ransomware documented chaining both legacy (EternalBlue) and modern (ProxyLogon) Microsoft flaws. Hybrid attackers often “double-dip” staging to guarantee one delivery channel survives first-line defenses.
    • Media dubbed it a “cheap-as-Ever” campaign: average ransom demand was only 0.45 XMR (≈ USD 95 at the time) to mass-target home users; nonetheless volume posed risk to underfunded SMEs.

Stay patched, isolated, and backed-up—you can break this particular chain.