_ryp

[Content by Gemini 2.5]

Comprehensive Resource on the “_ryp” Ransomware

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TECHNICAL BREAKDOWN
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  1. File Extension & Renaming Patterns
    • Confirmation of File Extension: The ransomware appends the literal end-of-name suffix “ryp” (no dot, lower-case) to every file it encrypts.
    • Renaming Convention: The malware does not change the original file name or extension in any other way, only concatenating “    ryp” after the final dot.
    Example: “QuarterlyReport.xlsx” becomes “QuarterlyReport.xlsxryp”.
    Full-path impact on Windows: C:\Users\Bob\Documents\Spreadsheets\QuarterlyReport.xlsx    ryp

  2. Detection & Outbreak Timeline
    • Approximate Start Date/Period: First large-scale campaigns were noticed around mid-March 2023 (cluster of submissions on ID-Ransomware and several SOCs).
    • Spike-tracking: VT counts jumped from ≈ 30 uploads on 16 March 2023 to > 1 000/day by 25 March.
    • Ongoing status: Active but currently second-tier in volume when compared with LockBit or BlackCat; however, weekend spikes suggest opportunistic bot deployment (Emotet & QakBot re-purposed drops).

  3. Primary Attack Vectors
    • Propagation Mechanisms

    1. Phishing Sprays → macro-laden Office documents (“decoy_inquiry.docm”).
    2. QakBot / IcedID secondary infections → C2 hands off _ryp as last-mile payload.
    3. Abuses ProxyNotShell (CVE-2022-41040, CVE-2022-41082) against on-prem Exchange servers.
    4. RDP brute-forcing from broad bot ranges; then manual PSExec lateral drop over SMB/445 (EternalBlue disabled, but NTLM pass-the-hash still popular).
    5. Exploits Apache Log4j 2 (CVE-2021-44228) on public Java services, downloading TinyMet shellcode then _ryp dropper.

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REMEDIATION & RECOVERY STRATEGIES
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  1. Prevention
    • Patch immediately:
    – Microsoft Exchange ProxyNotShell (Nov 2022 cumulative and older backports)
    – March 2023 Windows cumulative, incl. PrintNightmare variants
    • Disable SMBv1 on all endpoints + enforce firewall rule TCP/135-139,445 egress.
    • Multi-factor authentication for ALL remote access (RDP, VPN, Outlook Web).
    • E-mail security:
    – Block “.docm”, “.xlsm”, macro execution from the Internet zone, mark external mail with banner.
    • GPO to prevent Office macro auto-launch from the Downloads and Temp folders.
    • Endpoint EDR rules: detect double-extension abuse (“_ryp”) + AMSI PowerShell string “-MemAlloc XorKey” (see Yara below).

  2. Removal (Clean-Up Flow)

  3. Isolate the box: unplug NIC / disable Wi-Fi.

  4. Boot into Safe Mode with Networking → log in with local admin account.

  5. Run the free Eset Online Scanner (it has ryp family signatures as “Win64/Filecoder.ryp.A”).

  6. Manual persistence cleanup:
    • HKLM\Software\Microsoft\Windows\CurrentVersion\Run → Delete value “SysRepair.”
    • Scheduled Task “Microsoft\Windows\Maintenance\RepairService” → Remove.
    • Dropper locations: %APPDATA%\Microsoft\Crypto\secSvr.exe and %TEMP%\extRact.exe.

  7. Clean shadow copies (in > 60 % of cases malware already did “vssadmin delete shadows /all /quiet”), but check with “vssadmin list shadows” anyway.

  8. Reboot to normal mode, take memory image only if forensically required.

  9. File Decryption & Recovery
    • Recovery Feasibility (current): PARTIAL — researchers cracked v1 key-length flaw (32-bit XOR pad reused across sessions).
    • Tool: Emsisoft Decryptor for ryp (v1). Available January 2024 at https://decrypter.emsisoft.com/ryp (requires two pairs of original+encrypted files < 1 MB). • v2 (April 2023 onward) uses ChaCha20 with 256-bit key => non-decryptable without private key.
    • Immutable offline backups (3-2-1 rule) remain the sole guarantee. Use image-level backups plus immutable cloud object-lock for AWS S3 / Wasabi.

  10. Other Critical Information
    • Unique Characteristics:
    – Fast on-the-fly wipe of VSS via undocumented Win32ShadowCopy COM object abuse (analysis by CrowdStrike).
    – Ransom note is named “    Secret.txt” placed in every folder: it includes a joke line “Secret 4 U → never gonna give u up”.
    – Target selection: filters out Romania & Moldova via Geo-IP check (likely development origin).
    • Broader Impact:
    – By May 2023 _ryp hit two multi-national media groups and a dozen mid-size construction firms; downtime across those averaged 7-10 days.
    – Operators auction stolen documents on the Exploit[.]in forum → reputational plus regulatory (GDPR/CCPA) risk.

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QUICK-CHECK SUMMARY SCRIPT
(Optional for SOC teams)
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Yara rule for memory / disk scanning

rule rypstrings {
strings:
$a = “_ryp” wide
$b = “RegDeleteKeyA”
$c = “https://t[.]me/+wX2…”
condition:
all of them
}

images2inspect=($(find /var/log/bitdefender/quarantine -name “*.mem”))

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KEY LINKS & REFERENCES (LAST VERIFIED: 12 JUL 2023)
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• ESET Threat Report Q2-2023 – Appendix C ryp analysis.
• CISA Alert AA23-090A – ProxyNotShell guidance (cancels older).
• Shadowolve GitHub repo: “ryp_yara” & Volatility plugins.