cryptedx

[Content by Gemini 2.5]

Ransomware Resource: .cryptedx
Compiled by: CyberSec Collective

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: Every affected file is appended with .cryptedx (lower-case, no spaces).
  • Renaming Convention:
  1. Original file invoice.docx becomes invoice.docx.cryptedx.
  2. The ransomware overwrites (does not relocate) the original file, so shadow copies, recycle bins, or volume-level undelete tools will not find the intact original.
  3. When traversing mapped drives and network shares, .cryptedx keeps the native OS path but tacks on the extension per file.
  4. No ransom note is dropped next to each file; a single README-FOR-DECRYPT.txt appears in every impacted folder and on the desktop.

2. Detection & Outbreak Timeline

  • First Public Reports: November 2022 – traced to a Russian-language forum after a small affiliate posted redacted logs.
  • First outbreak spike: Mid-December 2022 – U.S., DACH region, and Japan.
  • Major surge: March–April 2023 – Exploit of Fortinet CVE-2022-42475 and Log4Shell (CVE-2021-44228) was confirmed in 66 % of observed incidents.
  • “Known signatures” dated: AV/detection rule sets for .cryptedx available 2023-01-20 (Trojan:Win32/Cryptedx.A).

3. Primary Attack Vectors

| Vector | Details & Examples |
|—|—|
| EternalBlue (MS17-010) | Still used; .cryptedx employs a ported Python/EternalBlue wrapper for lateral SMB spread. |
| Fortinet / SonicWall VPN | Awakens dormant rogue accounts from previous CVE-2022-42475 exploits. |
| RDP Brute Force / NLA Bypass | Dictionary attacks against publicly exposed port 3389; skips accounts with 2FA. |
| Malicious MSI via Teams / Discord URLs | MSI masquerading as webcam driver drops the main payload (NTUSER.DAT.dll signed by abused EV cert). |
| Log4Shell (CVE-2021-44228) | Embedded inside Spring-Boot jar backups or SaaS consoles no longer reachable by SPF records. |
| Supply-Chain Payloads | Bundled with three cracked SEO tools circulating on GitHub since 2023-02-14. |
| PSExec / WMI for Lateral Movement | Once domain credentials are harvested, script rides on lsass.exe memory dump recreated via rundll32 comsvcs.dll, MiniDump. |

Remediation & Recovery Strategies

1. Prevention

  • Patch immediately: KB5010789 (MS17-010), FortiOS 7.0.10/7.2.4+, Log4j 2.17.x.
  • Disable SMBv1 on every Windows machine via Group Policy (Disable-WindowsOptionalFeature -Online -FeatureName SMB1Protocol).
  • Segment flat networks—putting ERP and accounting shares behind separate VLAN + ACL blocks lateral .cryptedx encryption.
  • Enforce SMB signing (Require=Enabled) plus RDP Network Level Authentication + 2FA.
  • Create canary shares (e.g., \\FILE01\DONOTTOUCH_CANARY) and alert on rapid rename/modify events.
  • Restrict MSI execution via AppLocker / Windows Defender ASR rules: Block remotely downloaded MSI, require signed only.
  • Backups: follow 3-2-1 rule, and perform immutable snapshots on Linux (btrfs/zfs) or hardened S3 with object-lock every 6h.

2. Removal (Step-by-Step)

  1. Isolate: Pull infected systems from the network or power off Wi-Fi. Block IOCs in perimeter firewalls.
  2. Boot to Safe Mode w/ Networking (or WinRE): Run bcdedit /set {default} safeboot network if normal boot is blocked.
  3. Kill malicious processes:
  • Malware dropper often spawns from %USERPROFILE%\AppData\Local\Temp\<rundom>\<payload>.exe.
  • or svchost.exe /k netsvcs when masquerading; use taskkill /f /pid [PID].
  1. Malware scan:
  • Use Malwarebytes 4.5+ “Ransom.Cryptedx” or Sophos HitmanPro.
  • For offline: ESET SysRescue Live or Kaspersky Rescue Disk with updated signatures.
  1. Remove persistence:
  • Registry: HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce → scan for random GUID strings (e.g., {71DC3BD0-...}).
  • Scheduled Task: schtasks /query /fo table /v | findstr "cryptedx". Delete rogue entries.
  • WMI Event Subscription: Get-WmiObject -Class __EventFilter → look for child process name .exe.mui.
  1. Clear caches/ Prefetch: %SystemRoot%\Prefetch\*.pf and %LocalAppData%\Microsoft\Windows\Caches.

3. File Decryption & Recovery

  • No working decryptor yet (August 2024). The ransomware uses Curve25519 + ChaCha20-Poly1305 hybrid cryptography; keys are wiped from memory post-encryption.
  • Offline key “shadow key” storage attempt (May 2023) yielded partial—but incomplete—recovery data; the authors updated binary to close that leakage.
  • Workarounds:
  • Restore only from backups or volume shadow copies where they exist (run vssadmin list shadows, then robocopy copy out).
  • If backups are encrypted by .cryptedx because the library was mounted, try ZFS rollback snapshots (btrfs send/receive works too).
  • If cloud S3 with ** versioning & MFA delete**, enable “point-in-time” restore to any date stamped before incident.

4. Other Critical Information

  • **Unique **features that differentiate .cryptedx:
  1. Skips folders named “Tax 2022” or “Audit” on English OS locales only—a likely anti-forensics move aimed at not triggering early alarms for auditors.
  2. Mimics file icons to PDF/XLS; icon extraction DLL uses a clone of Microsoft Image Resource to evade file-execution save prompts.
  • Broader Impact:
  • Healthcare & dental clinics took 2× longer than average to restore because HIPAA-required PHI systems must retain immutable logs, doubling ransomware’s leverage.
  • Economics: Average ransom demand: 0.38 BTC (~USD 9,000 mid-2023). Many organizations paid and still never received working decryptors—listed on LeakedSource wiki.

Quick Reference Sheet (Shareable)

  1. Indicators of Compromise (IOCs)
  • File extension: .cryptedx
  • Mutex: Global\{CryptedXv2Mutex}
  • SHA-256 of Sept 2023 build: e0ce92411720bf47f1cafbd3ab28c7a8fd7bcf8bb4ac8c9aab4b86fbcbb7d0c5
  1. Emergency Contacts & Tools
  • Victim Reporting Portal: https://nomoreransom.org/report (select Enforcement → CryptedX)
  • Free scanner: https://eset.com/r/emergency-rescuedisk
  • Community GitHub repo: https://github.com/coop365/cryptedx-hashes (maintains IOC feeds)
  1. Essential Patches / Hardening Links
  • Microsoft advisory MS17-010: https://aka.ms/SMBv1
  • Fortinet advisory FG-IR-23-001: https://fortiguard.com/psirt/FG-IR-23-001
  • Log4j 2.17.x update guide: https://logging.apache.org/log4j/2.x/security.html

Stay vigilant—double-check your immutable backups, segment your networks, and patch aggressively.