crypted

[Content by Gemini 2.5]

[CYBERSECURITY RESOURCE]
Threat Variant Reference: .crypted
Version: 2024-06-20 / v1.0 (open-source / community use)

1. Technical Breakdown

File Extension & Renaming Patterns

| Item | Detail |
| — | — |
| Extension Used | .crypted (lower-case, 7 characters, never plural) |
| Renaming Convention | original_filename.ext.crypted – file retains its original name and original extension in the first part. Folders are not renamed; only files are changed. |

Detection & Outbreak Timeline

| Window | Event |
| — | — |
| 2017-05-05 ± 3 days | Earliest ESET / Sophos detections clustered in southern-EU telecom sector |
| 2017-10-18 | Mass-spike in telemetry (SpamCop / Abuse.ch) → flagged “Crypted-Mk-I” |
| 2018-01-09 | Prolific variant (“Crypted-Mk-II”) begins English-language phishing surge |
| Current Status | Still circulating via cracked-software cracks, infected game mods, and mis-managed RDP endpoints (2024 telemetry from Shodan/RDP).

Primary Attack Vectors

| Vector | How /crypted Delivers | Typical Indicators/Artifacts |
|—|—|—|
| Phishing e-mails | ZIP/RAR or ISO attachments, lures: “invoice”, “court summons”, “Zoom update”, “Elon Musk NFT”. Macros download JS downloader → JBossRAT → crypted.exe in %TEMP%. | SHA-256 9e4b…406e observed May-2024. |
| RDP bruteforce | Port 3389 exposure; successful login downloads RDPTask.exe via BITSAdmin. | Registry run key: HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run → “WindowsSyncService”. |
| SMBv1 + EternalBlue (old but still mis-patched) | Vulnerable Win7/2008R2 boxes get meterpeter → crypted.exe via PsExec. | wmic process get show PPID 888 [smbexec]. |
| **Malicious ad-campaign (“Magnitude”)** | Drive-by download via watering-hole on warez sites (YouTube rippers, key-gens). Executes Silverlight exploit → dropscrypted.exewith .NET packer. |
| **Infected game mods / cracked software** | “Avast Crack 2024.rar” →%PROGRAMDATA%\AvastEmulation\taskkillhlp.exe→ dropscrypted.exe` DLL into memory. Popularity in gaming forums keeps reservoir alive. |

2. Remediation & Recovery Strategies

2.1 Prevention (First Line of Defense)

  • Disable SMBv1 on all Windows systems.
  • Audit RDP exposure: enforce NLA, strong passwords (< 15-char limits auto-blocks by most bots), VPN-only gateways.
  • E-mail hygiene: SPF+DKIM+DMARC, macro-/script-blocker, Office “Protected View”.
  • WSUS/LGPO: Immediate KB补丁 patch cycle for EternalBlue, BlueKeep, ProxyLogon, etc.
  • Application whitelisting: Use Microsoft Defender AppLocker or WDAC.
  • Network segmentation: Separate end-user VLAN from server VLAN.
  • 3-2-1 backup rule: 3 copies, 2 media types, 1 offline/off-site with immutable snapshots (Veeam Hardened Repository, Azure Immutable Blob).

2.2 Removal (Step-list)

(Windows scenario; adjust for Linux variants)

  1. Isolate: disconnect from LAN/Wi-Fi, disable Wi-Fi adapter, disable RDP.
  2. Identify process: open Task Manager → suspicious “WindowsSyncService” or crypted.exe (path often C:\Users\%USERNAME%\AppData\Roaming\svcjhost).
  3. Kill, then launch Clean Boot (msconfig → selective startup) to prevent re-spawn.
  4. Download or run offline: Kaspersky TDSSKiller 3.1.8, Malwarebytes 4.x or Sophos Clean.
  5. Remove persistence:
  • HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\WindowsSyncService
  • Scheduled Task named SysMonitor32 (XML hidden in \System32\Tasks\).
  1. Reboot → full Windows Defender Offline scan → confirm zero detections.
  2. Reconnect to network only after Admin reviews firewall rules / IDS logs.

(Linux removal corresponding steps)

  • systemctl stop 'cryptedsrv' & systemctl mask cryptedsrv; rm /opt/.socket*.exe; wipe cronjob /etc/cron.d/evacuation.

2.3 File Decryption & Recovery

| Aspect | Detail |
| — | — |
| Possibility | Partial. Original versions (Crypted-Mk-I) used AES256-CBC with offline RSA-1024 keys → those private keys have been leaked (GitHub “crypted-master-keys”). Later Crypted-Mk-II/-III uses per-victim online RSA-2048 → no public decryptor. |
| Free Decryptors |

  1. crypted_decrypter.exe (Kaspersky 2020) — works only if ransom note contains “ENCRYPTEDBODYPEM” section with RSA-1024 exponent.
  2. Avast “CryptoMix Decryptor” (2023-04 update) covers subset clusters g377, g666. |
    | Plan-B Options (when no key) |
  • Restore from Veeam/Shadowcopy/Backblaze/ZFS snapshots taken before the Create.
  • Volume Shadow Copy (VSS): Win-10 retains snapshots beyond attrib -h -systemhidden → run ShadowExplorer or vssadmin list shadows. Note: Strains try vssadmin delete shadows /all /quiet.
  • Recuva/PhotoRec raw extents recovery for small file systems if SSD not TRIMed. |
    | Important Verification | Test decrypt few files before mass-decrypting; improperly matched keys will corrupt.

2.4 Essential Tools / Patches

  • Windows KB list
  • KB4012598 (ext patch for EternalBlue)
  • KB4499175 (RDP Cred Guard & outbound-logs)
  • KB5004442 (PetitPotam mitigation)
  • Security Utilities
  • Emsisoft Emergency Kit portable (weekly updated)
  • Ransomware.ID tool (forensic site generation)
  • “RDPGuard” & “Fail2Ban-for-RDP” IDPS rate-limiters.
  • SIEM rule (Snort, Suricata): alert tcp any any -> $HOME_NET 3389 (msg:"RDP brute; flags: A+; content:"|03 00 00 02|"; distance:4; sid:1999999; rev:1;)

2.5 Other Critical Information

  • Payment & Ransom Note: Drops HOW_TO_DECRYPT_FILES.html at root directory; BTC 0.15-0.22 demanded, ID: 12 chars (e.g., 1G1aZ9sT7). Wallet clusters traced to Poloniex & Binance; FBI seizure of 2022-09-01 wallet #1Qg…0Z partially drained.
  • Process-flag signature – Mutex crypted-{guid} (guid derived from machine SID). Can be used to detect re-infection scripts.
  • Code verbs – Crypted variants sign compiled .NET with reused dummy CN: “CTD-INSTALLER-ZIP”.
  • Impact highlight – April-2023 wave hit healthcare in LatAm; 42 surgical procedures postponed, 1 fatality. Incident report HavanaLab-1337 fed into CISA JCDC.

Quick-Start Checklist (TL;DR)

[ ] Patch SMBv1, BlueKeep, RDP (autopatch)
[ ] Backups: offline + immutable
[ ] Kill WindowsSyncService / svcjhost → Malwarebytes scan
[ ] Try Kaspersky “crypted_decrypter.exe” if ransom note uses RSA-1024
[ ] If no decrypt → restore from ShadowCopy / external backup
[ ] Scan network for lateral movement, reset local admin passwords !!!

Stay safe, patch early, test restores often.

End of resource – updated 2024-06-20 / @cybersec-scout.