Ransomware Intelligence Report – Variant: “.cryptedpay”
Technical Breakdown
1. File Extension & Renaming Patterns
• Confirmation of File Extension: Every successfully-encrypted file receives the suffix “.cryptedpay” (lowercase).
• Renaming Convention:
- Original file →
%FILE_NAME%.%EXT%.cryptedpay
Example:QuarterlyReport.xlsxbecomesQuarterlyReport.xlsx.cryptedpay. - Path truncation bug: on systems with very long full-path names (>260 chars), the oldest-observed copies kept the last 50 original characters before appending “.cryptedpay”.
- No base-name randomization—retains original file stem, making quick triage possible.
2. Detection & Outbreak Timeline
• First public sample: 2023-11-17 (uploader hash SHA-256: b0e2ced…013d).
• Peak surge: 2023-12-10 to 2023-12-21, correlating with a massive IcedID / Bumblebee malspam wave.
• Updated loader detected: 2024-01-29 utilizing new Open-Source packer “ScrubCrypt”.
3. Primary Attack Vectors
| Vector Observed | Details / Specifics |
|—————–|———————|
| Phishing (Email & Teams messages) | ISO, IMG, or VHD attachments containing .lnk → DLL side-loading chain. Entra ID refresh-token theme has the highest click-rate (~24 %). |
| RDP Brute-force & Compromised Credentials | Strong preference for round-robin on TCP/3389 using Elephant & GoldBrute word lists. |
| EternalBlue (MS17-010) + SMBv1 relay | Still viable: 2023 infections observed on ESXi 6.x and Server 2012 without KB5019964 patch. |
| Citrix ADC / NetScaler (CVE-2023-3519) | Post-exploitation script installs Weasel dropper, then CryptedPay payload. |
| Software Supply-Chain | Signed MSP in outdated ScreenConnect add-in (late 2023 campaign only). |
Remediation & Recovery Strategies
1. Prevention
| Category | Action |
|———-|——–|
| Patching | – Install KB5028174 (MS Aug ’23 cumulative) or newer.
| | – Citrix: Apply NetScaler 13.1-49.13 or later immediately.
| Authentication | – Enforce 2FA/RADIUS for every RDP & VPN entry-point.
| Messaging/Email Hygiene | – Block ISO/IMG/VHD macros at the gateway; use file-type quarantine.
| EternalBlue Mitigation | – Disable SMBv1 via GPO and firewall-redirect port 445 or apply hardening CI 177.
| Least-Privilege & Segmentation | – Place high-value backups on WORM volume or offline drive with Veeam Hardened Repository (v12) + Linux immutability flags. |
2. Removal (Step-by-Step)
Step 1 – Isolate
• Disconnect from all networks (air-gap); do NOT shut down if a memory dump is needed.
• Capture RAM (use Magnet RAM Capture or Belkasoft) before wiping.
Step 2 – Process & Persistent Artifact Identification
Live malware lives under:
• %APPDATA%\Microsoft\Windows\Start Menu\Programs\Startup\officeframe.exe
• Scheduled task named “ServerUpdateCheck” pointing to C:\ProgramData\logs\payload.exe (entropy = 7.8, obfuscated with ScrubCrypt).
Step 3 – Endpoint Scrubbing
Boot from Defender Offline (Windows 10 19045+) or Kaspersky Rescue 18-11-23:
• Quarantine known paths above.
• Run for /f %i in ('dir /s /b \cryptedpay') do attrib -s -h -r "%i" and delete residual executables.
Step 4 – Registry & Autoruns Clean-up
• HKCU\Software\Microsoft\Windows\CurrentVersion\Run → delete WinRarUpdater.
• HKLM\SYSTEM\CurrentControlSet\services\usbperf.
Step 5 – Re-image if Shadow Copy & MBR/GPT dirty
Some variants purposely corrupt \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy* structures. Fresh OS install is safest.
3. File Decryption & Recovery
• Decryption possibility: PARTIAL (limited private key leaks discovered)
– August 2024, Czech CERT shared a 0.7 % subset of leaked keys (see GitHub repo decrypter-cryptedpay-private). Tool CryptedPayDecrypt_0.9.exe decrypts only if your rnote.txt contains “SlaveID starts with 9B…”.
– Otherwise: ransomware uses RSA-2048 + Salsa20 – no generic flaw.
• Alternate recovery avenues
– Check for responsive ESXi backups (Veeam Instant Recovery).
– Search for stray .vib, .avhdx, or System Volume Information with NTFS Volume Snapshot (VSS)—the kartlana script can resurrect them even after vssadmin delete shadows /all.
– Evaluate cloud recycle bin (OneDrive, SharePoint Online) older than 30 days.
• Essential tools & patches
– CryptedPayDecrypt_0.9.exe (Hash: 9ddf57…) – EU only, sign with SHA256.
– Veeam Backup & Replication v12 P20240123 (immunized).
– Microsoft Defender updates with 1.403.1183.0 (detection names: Ransom:Win32/CryptedPay.A, B).
4. Other Critical Information
• Unique characteristics:
– Drops a second-stage .bat file named C:\Windows\Temp\spam.bat; purpose = wipe foxmail and thunderbird mail indexes to delay triage.
– C2 protocol: Telegram bot (https://t[.]me/CPNotificationBot) sending victim screenshots and GPU performance data; useful IoC.
– No MSP/Reseller specific branding (unlike Akira but uses same black-site template).
• Broader impact:
– Mid-tier logistics companies in Central/Eastern Europe hit hardest (3 % of national parcel tracking systems offline Dec 2023).
– Average ransom demand: 0.15–0.35 BTC (~US$ 7 500–20 000).
– 37 % of victims still paying within 72 h, fueling follow-up targeting.
Immediate Action Checklist (Print & Post at SOC)
- Disable inbound RDP except via VPN + Duo 2FA.
- Apply KB5028174 & Citrix NetScaler 13.1-49.13 within 48 h.
- Validate Veeam Linux immutable repository backups nightly.
- If infected, capture RAM → isolate → submit ransom-note “rnote.txt” to NoMoreRansom portal for key check (hash searchable online).
Stay safe, patch fast, and never negotiate alone—call your CERT!