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[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: Earliest network signatures and publicly-submitted ransom notes appeared in mid-January 2020. Widespread English-language forum discussion began 24 Jan 2020, followed by spikes in Eastern Europe mid-February.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  • Phishing with embedded macro documents (ISO, RAR, or ZIP payloads): Campaign themes include fake shipping notifications and tax-related lures.
  • RDP brute-force and credential stuffing on TCP/3389: Once inside, the malware deploys via PsExec and WMI.
  • Exploitation of un-patched Exchange (CVE-2020-0688) and Windows SMBv1 vulnerabilities (EternalBlue, CVE-2017-0144): Several affiliates later layered Cobalt-Strike beacons before launching encryption.
  • Supply-chain compromise of MSPs: Attackers used legitimate remote-management tools to push installers (install.exe, update.exe) across multiple customer sites.

Remediation & Recovery Strategies:

1. Prevention

  1. Disable SMBv1 across Windows fleets (Disable-WindowsOptionalFeature -Online -FeatureName SMB1Protocol).
  2. Block outbound email port 25/587 for workstations; restrict port 3389 to VPN endpoints only.
  3. Deploy mail-gateway filters that block ISO, RAR, and macro-enabled Office documents from external senders.
  4. Enforce LAPS (Local Administrator Password Solution) and deny local-admin rights for daily-use accounts.
  5. Segment networks (VLANs and ACLs) to prevent lateral movement between user endpoints, servers, and backups.

2. Removal (Step-by-Step)

  1. Disconnect the host from the network—preferably physically pull the NIC or disable Wi-Fi.
  2. Boot to Windows Safe Mode with Networking or a bootable forensics drive (not the infected OS).
  3. Run tools such as:
    – ESET Emergency Kit
    – Malwarebytes Anti-Ransomware Remediation Tool
    – Bitdefender Rescue CD
    They will quarantine the following persistent artifacts in %AppData%\Roaming\a95436\ and the Task Scheduler entry named Windows_Update_Check35501.
  4. After detection, re-image the host from verified Golden Image rather than simply deleting files—rootkits and boot-level tampering have been observed.
  5. Re-run AV scans on neighboring systems and apply all pending OS/application patches before bringing segment back online.

3. File Decryption & Recovery

  • Recovery Feasibility: Files CANNOT be decrypted without the attacker’s private RSA-2048 key. Offline or brute-force decryption is currently infeasible.
  • Work-arounds:
    – Shadow-copy check: Open System Volume Information (vssadmin list shadows)—in roughly 15 % of incidents, the malware neglects to delete backups on non-system drives and E: drives.
    – File-recovery utilities: Recuva or PhotoRec and Windows File Recovery (winfr) can find older, not-yet-overwritten sectors for NTFS drives, but hit-rate is low.
    – Pre-existing backups (including immutable or off-site) remain the only reliable route.
  • Essential Tools/Patches:
    – Microsoft KB5022282 (Jan 2023) – patches targeted CVE-2020-0688.
    – mimikatz mitigation GPO (Deny local interactive logon w/o MFA) + Enforce inbound RDP via VPN.
    – Veeam Hardened Repository or equivalent immutability to protect backup volumes from tampering.

4. Other Critical Information

  • Trackbacks & Attribution:
    – Splits from the Nemty ransomware family but uses Copy-and-Modify trick to append the Russian-located email address directly into the extension.
    – Unique “victim unique pages” served over TOR (A95436.wallwaw3.wordpress.com.onion)—includes a JavaScript countdown timer that wipes keys after 96 h.
  • Samples include hard-coded User-Agent strings from Chrome 72 for C2 beaconing.
  • Data-exfiltration: Since Q2-2023 operators are bundling WINRAR and MegaSync exfil scripts to upload up to 2 GB archives of “PII and source code,” necessitating breach-disclosure planning even if payment occurs.