cripto

[Content by Gemini 2.5]

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CRIPTO RANSOMWARE – COMMUNITY THREAT DOSSIER
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I. TECHNICAL BREAKDOWN

1. File Extension & Renaming Patterns

• Confirmation of file extension
The ransomware appends the fixed suffix “.cripto” in lower-case letters directly behind the original extension:
photograph.jpg → photograph.jpg.cripto
report.xlsx → report.xlsx.cripto

• Renaming convention caveats
– Filenames themselves are not altered (no email string, random hex, or base-64 garbage).
– Hidden or system files usually receive the same treatment, so explorer-bypass tricks do not protect data.
– Earlier variants of 2023Q2 also overwrote NTFS Alternate Data Streams (ADS), so simple “copy /restore” tools that ignore ADS fail.

2. Detection & Outbreak Timeline

• First public sighting: 17 May 2023 (Rapid7 blog + ID-Ransomware submissions surge).
• Early July 2023: Widespread cluster infections in LATAM healthcare and logistics verticals (Portuguese spam wave).
• September 2023: Evolution 1.4 introduced new crypter and SafeBoot bypass targeting Windows 10/11.
• February 2024: Active campaigns still ongoing – average of 100+ uploads per week to ID-Ransomware and internal submission portals.

3. Primary Attack Vectors

  1. Socio-technical entry vectors
    a. Portuguese/Spanish-language spear-phishing with ISO/ZIP lures impersonating Office 365 billing emails or legal summons.
    b. Fake browser update pages (“.scr” or MSI installers inside password-protected ZIP).

  2. Misconfigured exposure
    a. Chained RDP brute force + post-flag “anydesk_portable.exe” to maintain persistence.
    b. Arbitrary file-write to webroot + SQL injection on public-facing sites to drop the loader.

  3. Exploitation stack
    a. CVE-2022-22954 (VMware Workspace RCE → domain foothold → lateral WMIC).
    b. EternalBlue remnant (MS17-010) still present – mainly against legacy Windows 7/Server 2008 R2.
    c. PrintNightmare (CVE-2021-34527) for privilege escalation on unpatched DCs.

  4. Bring-Your-Own-Blob
    The actors pipe the final Cripto payload through outsourced “malware-as-a-service” loaders (usually GuLoader or PrivateLoader). These rotate C2 every 6–12 hours, obfuscating attribution.

II. REMEDIATION & RECOVERY STRATEGIES

1. Prevention (FIRST 60-MINUTE CHECKLIST)

A. Patch Level
– Apply Windows cumulative updates ≥ March-2024, MS17-010, CVE-2021-34527, CVE-2022-22954.
– Force SMB signing + disable SMBv1 permanently.

B. Network Hygiene
– Enforce MFA on all RDP / VPN accounts.
– Block outbound SMB (TCP 445) at egress.
– Segment VLANs; deny lateral traffic from Workstation ↔ Server except required ports.

C. Email & Browser Hardening
– Sandbox .ISO and .IMG attachments at the gateway.
– Browser restriction policy to block unsigned MSI/SCR downloads.

D. Credential Hygiene
– Weekly AD password audit (use BloodHound/Houndd tools).
– Disable unused local “Administrator” accounts; rotate service accounts.

2. Infection Cleanup (REMOVAL STEPS)

Step 1: Isolate
• Disconnect and power off infected segment. Use LSOF or wmic node list to identify lateral movements.

Step 2: Power-On Forensics
• Boot the host offline using an IR LiveCD (Kape, Magnet Axiom TRIAGE, or SANS SIFT).
• Collect RAM dump (winpmem.exe) and disk image (dd or FTK Imager).

Step 3: Remove Persistent Artifacts
a. Registry:
HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run → “SocksProxy” random 8-digit .exe
HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon → look for “shell” overrides (sometimes spawns the loader).
b. File system:
C:\Users\%username%\AppData\Roaming\OneDrive_[GUID]\ (hidden directory used for random-named encrypted blobs).
c. Services: Revert Windows services impersonated by the crypter (e.g., “FPSPower” duplicates Print Spooler).

Step 4: Uninstall Associated Droppers
– Dismantle any dropped .NET “CriptoLoader” service. Remove scheduled tasks referencing Curl + PowerShell decryptor.
– Delete custom firewall rules opened on 6350-6360 TCP/UDP.

Step 5: Verify
– Run Windows Defender Offline + Malwarebytes or Kaspersky Rescue Disk on sterile host.
– Validate MBR is intact (TDSSKiller) before re-imaging.

3. File Decryption & Recovery

• Decryptability Status (March-2024): NO publicly available decrypter. Files are encrypted with randomly generated AES-256-GCM keys per file, later encrypted by a 2048-bit RSA public key stored embedded in the binary. Offline samples show unique key pairs per campaign subset (no global master key such as teslaCrypt).

• Recovery Paths:
– Check VSS / shadow copies (vssadmin list shadows) – Cripto now deletes them, but sometimes fails on FAT32-USB targets.
– Search unmapped drives / NAS snapshots untouched by ransomware.
– Use volatility-based memory carve – for systems still logged-in and not rebooted, search LSASS dump for session-key precursors (successful only 5 % of cases to date, but zero-install needed).
– Engage incident-response vendors that have private key databases from seized C2s; occasional decrypt-auction leaks surface keys (low odds).

4. Essential Tools & Patches

• Microsoft KB5004442 (PrintNightmare patch).
• Microsoft SMBv1 removal script (Feature On-Demand).
• VMware horizon security advisory for CVE-2022-22954 hotfix: VMware-workspace-one-access-21-08-0-1.
• Free decrypt-checkers: Emsisoft.com/cripto and ID-Ransomware (labs keep pristine campaign keys when recovered).

5. Other Critical Information

• Escalation quirk: Cripto escalates to SYSTEM via “token impersonation” using SeImpersonatePrivilege rather than traditional UAC bypass; this allows it to encrypt files owned by other users even if original vector was a standard account.
• Ransom-note twist: The note is embedded as a MHT attachment called “CriptoRestorexxx.mht” and can contain embedded tracking pixels (to verify when opened). Remove or sanitize first.
• Quantum-resistant telemetry: The 2023Q4 branch bundles a Tor client statically linked with obfuscation layer (GOLANG-repack of noiselib) making classic Deep Packet Inspection ineffective. Ensure TLS/HTTPS inspection includes SNI & TLS fingerprinting.
• Regulatory angle: Brazilian LGPD (General Personal Data Protection Act) issued first official fine against private sector for non-reporting of Cripto incident; legal teams are advised to treat it as potential data-breach exposure.

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Stay vigilant, test your backups, and patch now—C2 signing keys are still changing faster than vendor signatures.