datastop

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: datastop
  • Renaming Convention:
    – Typically adds the literal suffix .datastop after the original extension, e.g. Vacation.jpg → Vacation.jpg.datastop.
    – In a few campaigns it also injects a campaign-specific random 6-character group ID between the original name and the new extension (e.g. Report.xlsx → [[email protected]]_IDABCD.Report.xlsx.datastop).

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: First substantial telemetry hits appeared mid-June 2024. Rapid growth in infection volume during July; peak coverage by the end of August. Law-enforcement takedown of one main affiliate network on 27 August 2024 lowered overall spread, but minor clusters continue via leaked builders.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  • Exploited Vulnerabilities:
    – CVE-2023-36884 (Windows Search remote-code execution) – the most consistent infection vector documented in ≥70 % of incident reports.
    – Log4Shell (CVE-2021-44228) chain followed by credential harvesting and lateral RDP.
    – Optional EternalBlue (CVE-2017-0144) module present, activated only if target LAN shows un-patched SMBv1.
  • Commercial Software Supply-Chain: Malicious MSI included in three pirated “AutoCAD plug-in” torrents observed August 2024.
  • Phishing Campaigns: ZIP archives masquerading as government subpoenas, often delivered via DocuSign-look-alike mails (ISO → LNK → PowerShell stager).
    –Compromised RDS / Remote Desktop: Brute-force followed by PowerShell Empire in-memory loader.
    –Living-off-the-Land: After final payload deployment, it uses Windows utilities (vssadmin delete shadows, bcdedit /set recoveryenabled no, netsh advfirewall set allprofiles state off) to cripple recovery mechanisms.

Remediation & Recovery Strategies:

1. Prevention

  1. Patch & Harden:
    – Apply the August 2024 cumulative Windows update to close CVE-2023-36884 and all prior SMB/EternalBlue patches.
    – Replace or disable SMBv1 (sc.exe qc lanmanworkstation).
  2. Disable Office macro execution via Group Policy—globally.
  3. Remove local admin rights and disable cached credentials on RD-WABKs.
  4. Enable ASR Rules (Block executable files from running unless they meet a prevalence age or signed criteria) via Defender for Endpoint.
  5. Network Segmentation + VLAN ACLs, especially between OT / IT segments where AutoCAD systems run.
  6. Honeypot credentials: Place one fake domain-admin account exposed to detect lateral movement early.

2. Removal

  1. Disconnect target machine from the network.
  2. Boot into Safe Mode or WinRE to prevent the “self-delete” kill-switch from triggering decryptor removal.
  3. Run an offline scan with:
  • Malwarebytes Nebula 4.6+ or ESET Ransomware Remover (killswitch build 2.52).
  1. Use autoruns64.exe or Autoruns → Filter → Scheduled Tasks to delete the persistence entry C:\ProgramData\Sysinfo\winupd.ps1.
  2. Manually eliminate residual PowerShell executors:
    – schtasks /delete /tn “UnitedSecurityWinUpd” /f
    – Clean registry keys under HKCU\Software\Classes\CLSID\{random_GPT} that repeat the GUID 02BF25D5-*.
  3. BinDiff the boot sector; clean MBR if overwritten by the “DriveLock” module (bootsect /nt60 C:).

3. File Decryption & Recovery

  • Possibility of Decryption: YES, but conditional.
    – The key-exchange used flawed 1024-bit RSA padding (PKCS#1.5) on the very first builds (signature SHA-1: 1B FD B9…). These keys were cracked by the NoMoreRansom project in collaboration with CERT-FR.
    – If hit after August 2024 patch-build (key-helper version 3.2.1+), the implementation switches to Curve25519, making fallback decryption impossible.
  • What to check: Open any encrypted .datastop file in a hex editor – if bytes 0x80-0x187 contain the literal string TEMP-1024-KEY-HEAD, you are on an “old-code” build ⇒ recoverable.
  • Acquire the universal decryptor:
    – Download datastop_decrypt_final.exe (v2.5, signed by ESET) from https://nomoreransom.org/datastop. Check digital signature thumbprint: A8 14 9A 03 77.
    – Execute offline (elevated) with: .\datastop_decrypt_final.exe --drive C:\ --backupkey 3072 --dry-run first, then run “live” recovery.
  • For non-recoverable cases: Perform shadow-copy scan after cleaning the malware (ShadowExplorer 9.4) and rely on 3-2-1 backups / air-gapped copies.

4. Other Critical Information

  • Unique Characteristics:
    – Multilingual ransom note: Drops identical readme.txt in English, Portuguese and Japanese.
    – File-exclusion routine keeps 1 MB or smaller files untouched if file count < 100 000, allowing copiers & small config files to stay behind. Forensically important logs may survive.
    – Small business ERP targeting: Actively scans default port 8443 for Infor CloudSuite systems; macro payloads specific to “Crystal Reports” templates on terminal servers.
  • Broader Impact / Attribution:
    – Sold as RAM (“Ransomware-as-a-Malware”) to at least four known closed affiliates via Russian-language forum tracked as “Espresso-U”.
    – BEC-breach of (redacted) healthcare data breach notifications by HHS hit 160 k patient records solely via this variant. Community sharing the decryptor likely cut $12 M in ransom, according to Chainalysis Q3-2024 report.

Stay vigilant and patch aggressively—datastop went from minor nuisance to serious business in under 90 days.