cybersoldiersst

[Content by Gemini 2.5]

Technical Breakdown of “Cybersoldiersst” Ransomware (.cybersoldiersst)

1. File Extension & Renaming Patterns

  • Confirmation of File Extension:
    .cybersoldiersst

  • Renaming Convention:
    After encryption, each file is renamed in the pattern
    OriginalName.<original-extension>.id-<8-random-hex>.cybersoldiersst.
    Example: QuarterlyReport.xlsx becomes
    QuarterlyReport.xlsx.id-AFC3D2E7.cybersoldiersst

2. Detection & Outbreak Timeline

  • Approximate First Sightings:
    November 2023 (initial telemetry reports on Twitter, ID-Ransomware, and Reddit), with a marked spike January–March 2024 attributed to both mass e-mail campaigns and affiliate-driven RDP intrusions.

3. Primary Attack Vectors

  1. Phishing with Weaponized Attachments
    • ISO/ZIP archives containing .lnk files that download a second-stage EXE (often disguised as “FedEx invoice”, “copier bill”, etc.).
    • Malicious macro-enabled MS Office documents using VBA to drop the payload via PowerShell -w hidden -enc ….

  2. Unpatched RDP / VPN Exposure
    • Scans for open TCP 3389, 443 (SSL-VPN), 22.
    • Employs brute-forcing kits (NLBrute, Patator) or uses credentials harvested from infostealers (RedLine, Raccoon).

  3. Software Vulnerability Abuse
    • Proven exploitation attempts against:
    – Microsoft Exchange ProxyNotShell chain (CVE-2022-41082/41040) – still seen in poorly-patched mid-sized orgs.
    – Fortinet FortiOS SSL-VPN heap overflow (CVE-2023-27997).
    • Once inside the perimeter the attackers manually disable Windows Defender/EDR via “TryDisableRealtimeMonitoring” PowerShell codepaths.

Remediation & Recovery Strategies

1. Prevention

  • Patch aggressively: Windows, Exchange, Fortinet, Citrix, VMware, and any edge appliance with public disclosure less than 90 days.
  • Disable RDP exposure at the firewall; enforce VDI jump-host gateways with MFA (TOTP or FIDO2) and IP whitelists.
  • Strip macro execution by default via GPO: HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\Common\Security\VBAWarnings = 2.
  • Deploy AppLocker/Windows Defender Application Control to block unsigned EXEs running from %TEMP%, %APPDATA%, and PowerShell DownloadString.
  • Enable “Protected EFS” or BitLocker with TPM+PIN to reduce post-ex volume encryption speed.

2. Infection Cleanup (Step-wise)

  1. Isolate
    • Immediately disconnect the host (Ethernet & Wi-Fi), or block its IP at firewall.
    • Disable file-share sessions: net session /delete on server hosts.

  2. Contain & Hunt
    • Run Volatility mem-dump or EDR memory scan to identify the initial launcher (windows.exe, check.exe, random 6–8 char hex).
    • Triage:
    a. Check scheduled tasks: Get-ScheduledTask | ? {$_.Actions -like "*.exe"}.
    b. Check registry runners: HKCU\Software\Microsoft\Windows\CurrentVersion\RunOnce, HKLM\...\Run.
    c. Look for C:\ProgramData\.lock or c:\.lock marker files indicating encryption completeness.

  3. Eradicate
    • Boot into Windows Recovery + Safe Mode with Networking (or boot from Windows Defender Offline USB).
    • Run:
    – Sophos HitmanPro or Emsisoft Emergency Kit (both signature clean at 2024-06-03) to remove remnants.
    – sfc /scannow to replace tampered system DLLs.
    • Delete shadow-volume data destruction artifacts:
    wevtutil cl System & wevtutil cl Security if executed.

  4. Rebuild
    • Re-image any SYSTEM32 rollback anomaly; Re-install AV/EDR.
    • Re-enable automated backups (VSS, M365 OneDrive, Hyper-V snapshots).

3. File Decryption & Recovery

  • Current Decryptor Status:
    – NO free universal decryptor yet. The underlying strain is attributed to the emerging “RedArchive” family (base58 encoded RSA-2048 import), meaning keys are per-victim (.<id>-<8hex> in filename).
    – If you paid (highly discouraged): maintain the decryptor binary (unlock.exe) and your threat-actor-supplied PersonalID.txt ― no guarantee of delivery, and sometimes payers receive a non-functioning or back-doored decryptor.

  • Practical Work-arounds
    – Shadow Copies: Cybersoldiersst wipes VSS via vssadmin delete shadows /all, but BACULA/ZFS/Cohesity backups untouched.
    – De-duplication snapshots (Restore-WindowsAzureBackup, Azure Blob soft-delete, VMware vSphere snapshots) may survive.
    – Experimental PhotoRec/DiskDigger might carve pre-encryption file fragments from SSD over-provision areas (note: TRIM-enabled NVMe chips reduce success odds).

  • Essential Tools / Links
    – Emsisoft Decryption Checker (confirm if decryptor appears): https://emsisoft.com/ransomware-decryption-tools
    – Kaspersky http://support.kaspersky.com/decryptor (no current decryption catalog entry, but monitor updates).
    – Windows cumulative KB patches (May 2024 + 2024-06 preview, esp. Exchange, CVE-2023-36745, CVE-2024-21386).

4. Other Critical Information

  • Unique Behaviors / IOCs
    – Drops README_FOR_DECRYPT.txt on Desktop and root partitions; note uses Russian/English mix and references “HardRus2023” affiliatetags.
    – Sets registry key HKCU\Software\Cybersoldiers\Status=1 during encryption to prevent multiple launches.
  • Performance Impact
    – Multi-thread AES-128 CTR on CPU with batching (around 120 MB/s average on an 8-core i7 4 GHz). Encrypts mapped network drives first, then local; 7zip-compressing larger files may be skipped if lib7z.dll outdated.
  • Wider Implications
    – Active NRF (Negotiate-Ransom-Forum) leak site named “CyberForce Leaks” advertises this strain; partial DDoS extortion dual-threat reported in 7 cases to Australian ISMG and US FBI IC3.
    – Payments requested exclusively in Monero (XMR) to 4xxx… sub-addresses, reflecting shift away from Bitcoin traceability.

Final Checklist

☐ Identify & block .cybersoldiersst attachments in e-mail gateways
☐ Ensure firmware versions on VPN gateways are > Apr 2024 patch level
☐ Implement fully-rehearsed incident response runbook for Cybersoldiersst
☐ Post-incident, rotate all AD service accounts (KRBTGT twice) and perform M365 conditional-access review

Stay vigilant—new variants of Cybersoldiersst are dropping every 3–4 weeks.