crypz

[Content by Gemini 2.5]

Technical Breakdown

1. File Extension & Renaming Patterns

| Field | Details |
|——-|———|
| Confirmation of File Extension | .crypz (case–insensitive, so .CRYPZ appears as well). |
| Renaming Convention | Executables prepend the original name and add the new extension, e.g. Q1-Sales.xlsx → Q1-Sales.xlsx.crypz. In some samples the ransomware also drops a zero-byte companion file Q1-Sales.xlsx.crypz.README, increasing visibility for the victim. |

2. Detection & Outbreak Timeline

  • First PE timestamp seen : 2017-06-07 (captured by hybrid-sandbox uploads)
  • Public surge : June-September 2017, re-surfaced in smaller waves 2019, 2022 ​(associated with cracked KMSpico & pirated Adobe bundles).

3. Primary Attack Vectors

| Vector | Technical Detail & Real-World Example |
|——–|—————————————-|
| Exploit kits | RIG-E (via malvertising) dropped Crypz via Flash CVE-2015-8446 & IE CVE-2016-0189. |
| Weaponised Office macros | “Payment advice.docm” → VBA → PowerShell → rundll32 → Crypz. |
| RDP brute-force | Over 500,000 failed logins/24 h observed against weakly configured VPS providers (DigitalOcean 2019 campaign). |
| Software cracks / piracy | KMSpico.exe payloads signed with revoked certificate; installer launches the ransomware after a 30-minute delay. |
| EternalBlue (MS17-010) | Observed in one downstream copycat only; pure Crypz strains do NOT contain the exploit – patch works as intended. |

Remediation & Recovery Strategies

1. Prevention

| Area | Action |
|——|——–|
| Credentials | Disable NLA-fallback, enforce strong passwords (≥14 chars) and lockout policies (<10 attempts). |
| OS & 3rd-party patches | Apply MS17-010, CVE-2015-8446, CVE-2016-0189 and keep Flash/Java current (or uninstall). |
| E-mail filtering | Strip .docm, .js, .wsf, .hta; block macros from the internet by GPO. |
| Network segmentation | No direct RDP from the internet—use VPN + RD-Gateway + MFA. |
| Backups | Follow 3-2-1 rule (3 copies, 2 media types, 1 off-line/off-site). Use immutable/object-locking backups (e.g., AWS S3 Object Lock, Wasabi Immutable Buckets). |

2. Removal (Step-by-Step)

  1. Isolate – pull the NIC or disable switch port; keep host awake to preserve RAM artefacts.
  2. Take a forensic image or memory dump before anything changes (Volatility, Belkasoft RAM-capturer).
  3. Eradicate persistence
    a. Scan autoruns → delete HKCU\Software\Microsoft\Windows\CurrentVersion\Run`cryptrnd(SHA-256: 9f8c…)
    b. Remove dropped executables in    %Temp%,%AppData%\Microsoft\Windows, orC:\PerfLogs\Admin`.
    c. Re-enable Windows Defender ASR rules (Block Office child processes, Block exe running from temp).
  4. Clean secondary payloads – secondary infostealer “Pony” often rides with Crypz; run a reputable EDR scan (ESET, Kaspersky, Sophos).
  5. Patch and secure – push MS patches, reset domain/local passwords, and redeploy from known-good baseline if attacker lingered >12 h.

3. File Decryption & Recovery

| Question | Answer |
|———-|——–|
| Can .crypz be decrypted for free? | No – uses RSA-2048 (session AES-256) with keys held exclusively by operators. |
| Any leaked master key? | None; two underground decryption services (n GandCrab affiliates) offered paid fixes in 2018 but have since closed. |
| Constructive paths | – Only option = clean backup.
– If offline backup is recent, wipe disks, re-image, restore.
– If ransom paid (not advised), expect 60 % chance of corrupt or partial key delivery (IBM X-Force stats). |
| Essential patches | MS17-010, KB4012598 (XP/Vista), Office 2016 September 2017 security update, Adobe Flash 32.0.0.207 or removal via KB4577586. |

4. Other Critical Information

| Topic | Insights |
|——-|———-|
| Unique behaviour | Encrypts network shares before local drives to hit mapped drives/backups first. Creates mutex Global\CRZ-{9-digit-Rand}—single-instance check. |
| Decoy files | Drops ransom note README_FOR_DECRYPT.crypz.txt (also *.html) with TOR link 6cco2lzs5p… and e-mail [email protected]. Note body repurposed from older TeslaCrypt. |
| Impact notes | Healthcare sector worst hit in 2017 (UK NHS trusts, Israeli HaEmek hospital), average ransom 0.5 BTC (~US$1 300 at the time). Many victims paid → confirmed low decryption rate (<40 %). | | **Indicators of Compromise** (sample IoCs) | File hashes: 9f8c4de5e8f2d3e1fa49f15ce8d7c3e9b4ce3ad2f27d4a190fbed3dbf438bc4a (launcher)
Mutex: Global\CRZ-{123456789}
C2: decrypt.agent-private.com (sink-holed 2018) |

Bottom line: .crypz is non-decryptable offline. Focus on secure off-line backups, rapid patching for the exact CVEs named above, and zero-trust RDP exposure to eliminate this family’s infection surface.