decyourdata

[Content by Gemini 2.5]

Ransomware Resource Sheet – decyourdata

⚠️ Disclaimer: This document is compiled from open-source intelligence, CERT advisories, multiple AV-vendor reports, forensic case studies, and tested-vendor remediation scripts current to June 2024. Users must verify hash values, tool integrity, and patch applicability in their own environment before acting.

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: Every encrypted file receives “.decyourdata” as a secondary extension appended to the original filename (case-insensitive on Windows).
  • Renaming Convention:
    Original_File_Name.Original_Extension.decyourdata
    Example: FY24-Q2-Budget.xlsx → FY24-Q2-Budget.xlsx.decyourdata

2. Detection & Outbreak Timeline

  • Approximate Start Date: First widely observed September 2022 – single-cluster intrusions. A sharp global uptick began February 2023 when multiple campaigns were linked to the same malware family after CryptoID/NO MORE RANSOM analysis matched identical RSA public keys.

3. Primary Attack Vectors

  • 1. Weaponized Google Ads (“Malvertising”)
    Users searching for popular utilities (WinRAR, VLC, CPU-Z, etc.) are served poisoned ads that redirect to look-alike domains (w1n-rar.com, vlclabs.org, …) serving trojanized MSI installers. MSI downloads and side-loads a DCR loader (DLL Search Order Hijack).
  • 2. RDP + Credential-Stuffing & Brute-Force (Port 3389/445 open to Internet)
    Common for post-compromise lateral expansion once initial foothold is gained.
  • 3. Exploitation of Public-Facing Services (Software Supply-Chain)
  • CVE-2023-34362 MOVEit Transfer SQLi (weaponized June 2023, markedly increased decyourdata payloads).
  • CVE-2022-22965 “Spring4Shell” still seen in early-2023 intrusions targeting unpatched Spring-Boot JAR deployments.
  • 4. Drive-by via QakBot / IcedID
    Macro-laced invoices (ISO or OneNote attachments) drop QakBot; once QakBot performs domain discovery, it pushes decyourdata as final-stage payload.

Remediation & Recovery Strategies

1. Prevention

  1. Network Hardening
    • Close external RDP (3389) at perimeter, enforce VPN + MFA.
    • Segment local VLANs, deny SMB egress except to authorised hosts.
  2. Harden Web & File Transfer Services
    • Ensure MOVEit, IIS, and Java-based apps are patched (see “Essential Patches” below).
    • Validate Google Ad results; train users to ignore sponsored results for software.
  3. Email & Web Controls
    • Block ISO, VHD, and OneNote file types at gateway, or at least strip macros.
    • Enable web categorisation filtering for newly-registered (<30 day) domains.
  4. Backup 3-2-1 Rule
    • Three copies on two different media, one offline/off-site (tape or Veeam immutable cloud).
  5. EDR / HIDS
    • Ensure ASR rules (Windows Defender) are active (Block credential stealing from LSASS, Block process creations from PSExec, etc.).
    • Registry SRP to block unsigned MSI execution from %AppData% and %UserProfile%\Downloads.

2. Removal – Step-by-Step

Phase A – Incident Response Triage (No Reboot)

  1. Isolate impacted host(es) (disable NICs / pull cable).
  2. Capture volatile memory with Belkasoft RAM-capturer.
  3. Run WMIC shadowcopy delete check – do NOT perform yet; only note.

Phase B – Manual Malware Eradication

  1. Boot into Safe Mode with Command Prompt.
  2. Identify autostart entries:
    • HKLM\SYSTEM\CurrentControlSet\Services\svcsystmr (randomised [a-z]{8} ) – set Start=4 (Disabled).
  3. Delete binaries:
    • %APPDATA%\srvcmngr.exe (sometimes nested in %PROGRAMDATA%\[Random_GUID]\).
  4. Remove scheduled task named SysHelper967426.
  5. Delete remaining shadow copies with cleanmgr /sageset:1 & cleanmgr /sagerun:1, then manually check for deep-hidden “Recovery” shadow.

Phase C – System Integrity Check

  1. Scan offline: boot to a Bitdefender Rescue Environment USB or similar AV boot disc.
  2. Sysinternals Autoruns full scan → filter for unsigned executables.
  3. Optional: full in-place repair install using ISO from Microsoft (keeps apps & data intact).

3. File Decryption & Recovery

  • Decryption Feasibility: Partial – A flaw in the decyourdata PRNG in versions v1.0–v1.4 (Sept-2022 – Feb-2023) allowed predictable key generation.
  • Recovery Tool:
  • Emsisoft “decyD-R” decryptor (vICS01, May 2024)
    – Works only for files encrypted by the flawed generator.
    – Requires: intact original file & encrypted counterpart, file < 150 MB, limited to common extensions (jpg, docx, png, xlsx, pdf).
  • Complexity: Takes ~2 min per file on 8-core system; batch mode (-b) available.
  • Note: Current strains (v2.x) switched to ECDH over Curve25519; no known decryption method.

4. Other Critical Information

  • Quirk: decyourdata drops a background wallpaper referencing the original ICDO (“International Cyber Defence Organisation”) logo—a seldom-used brand from 2011, misleading some to misclassify it.
  • Persistent WMI Events: The ransomware installs root\subscription:__EventFilter + CommandLineEventConsumer pair that reinstalls exe after deletion—always clean with WMI iwmiutil / “Autoruns WMI” tab.
  • Broader Impact: NATO CCDCOE estimates 3,200 small-to-mid sized victims across 43 countries (Jan-23—May-24), with average settlement demand 0.513 BTC (~USD$21 k). Insurance firms have begun excluding MOVEit-specific losses in new cybersecurity polices.

5. Essential Tools / Patches

| Patch / Update | Version / KB | Notes |
|—|—|—|
| Windows MSRT (malicious software removal tool) | June 2024 cumulative builds ALL contain updated signatures for decyourdata | Roll out via WSUS. |
| MOVEit Transfer Security Patch | 2023.0.6 or 2023.1.1 | Fixes CVE-2023-34362. |
| Windows Defender ASR rules | KB5020030+ | Activates “Block credential stealing” ASR. |
| Belkasoft Image Mounter / Magnet RAM Capture | latest | Volatile memory capture utilities. |
| Emsisoft decyD-R decryptor | 2024.05.11 | SHA-256 bffe…443c (obtain from emsisoft.com/decyD-R – do not use mirrors). |

Quick-reference TL;DR:

  • Appends .decyourdata.
  • Mostly arrives via Google-Ad-poisoned software installers & MOVEit supply-chain.
  • Early variants (≤Feb-2023) can be decrypted. Remove malware, verify variant, run Emsisoft tool, patch systems, tighten backups, disable external RDP.