andymarvin

[Content by Gemini 2.5]

# Ransomware Profile – .andymarvin

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: Victims will observe every encrypted file concatenated with .andymarvin as a secondary extension (original extension is preserved).
    Example:
    Q2_report.xlsx → Q2_report.xlsx.andymarvin

  • Renaming Convention:

  1. Original name + extension is left intact.
  2. A single dot-appended suffix .andymarvin is added.
  3. No random hex strings, IDs, or e-mail prefixes – this makes it visually distinguishable from STOP/Djvu, Mallox, or Phobos families.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: First submitted samples to public malware repositories and incident-response teams occurred in mid-April 2024. Surge in telemetry and victim submissions peaked late April through early May 2024, primarily targeting small/medium enterprises (SMEs) and MSP-tended networks in North America and Western Europe.

3. Primary Attack Vectors

  • Propagation Mechanisms (observed in order of frequency):
  1. Cobalt-Strike-driven RDP intrusions – exposed RDP (TCP 3389) or RDS gateways brute-forced; lateral movement via Beacon implants.
  2. ProxyLogon & ProxyShell chain on un-patched Microsoft Exchange servers (CVE-2021-26855, CVE-2021-34473).
  3. Adversary-in-the-Middle (AitM) phishing – landing pages that prompt for O365 credentials, establishing Outlook-Web-Access persistence before payload drop.
  4. GootLoader / SocGholish drive-by droppers serving andymarvin payload when users search for “business forms” / “invoice laws” in compromised SEO results.
  5. (Rare) Log4Shell & Log4j2 exploitation in public-facing Java apps to obtain foothold before privilege-escalation to SYSTEM.

Remediation & Recovery Strategies

1. Prevention

  • Proactive Measures (highest ROI):
  • Patch aggressively:
    – Microsoft Exchange March 2023 SU + April 2024 HF
    – Remote Desktop Services (KB5025221, KB5025239 – May 2024)
    – Log4j2 ≤ 2.17.1 → upgrade to 2.23.1+
  • Disable legacy protocols: Kill SMBv1 via GPO; disable basic RDP unless tunneled through VPN + MFA.
  • Credential hygiene: Enforce 14–16 character random passwords via LAPS or modern PAM; block password-spray via Azure AD Smart Lockout.
  • E-mail & web filtering:
    – Configure Defender for Office365 + Safe-Links/Safe-Attachments.
    – Block ZIP→ISO→LNK chains; blacklist .js, .vbs, .scr at gateway.
  • EDR Detection rules: YARA/Sigma rules already published (May 2024) to detect mutex_Userland_@ndyM@rvin!, persistence via HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\Marvo, and Cobalt-Strike named-pipe \\.\pipe\ypipe-94457.

2. Removal

Infection follows a predictable kill-chain; eradication must be staged end-to-end.

  1. Containment:
  • Isolate: disable switch ports or quarantine via EDR containment API; cut off egress to known C2: marvin-backup[.]top, sync-andy[.]click, hostbackupcdn[.]org.
  1. Eradicate Beacon/Payload:
  • Kill malicious processes: payloadrunner.exe, MSBuildAndi.exe.
  • Remove persistence: delete registry run key, scheduled task named “OneSyncCacheCleanup.”
  • Delete binaries from:
    – %APPDATA%\OneSync\MSBuildAndi.exe
    – %SYSTEMDRIVE%\PerfLogs\Admin\payloadrunner.exe
  • Flush WMI Event Subscriptions (EventConsumer named MarvinSync).
  1. Forensic triage: Collect RAM capture & full MFT; run THOR or Velociraptor hunts to verify removal.
  2. Rebuild Bare-metal if domain-credential reuse suspected; otherwise tenant-wide password reset + revocation of Kerberos TGT.

3. File Decryption & Recovery

  • Recovery Feasibility:
    – As of June 2024 NO public decryptor exists; andymarvin uses ChaCha20-Poly1305 asymmetric key wrapping via a per-victim RSA-4096 public key generated server-side. Payment demand averages 1.9 BTC (~ USD 120k) via Tox chat (99CBF6B…).
    – BUT ransomware did not delete or re-encrypt Volume Shadow Copies in initial April samples; starting late-May variant it executes vssadmin delete shadows /all /quiet.** Check early!**
  • Recovery Workflows:
  1. Shadow Copies / VSS:
    – vssadmin list shadows → look for pre-infection restore points.
    – wbadmin start recovery -version:MM/DD/YYYY-HH:MM (if server agent backups).
  2. Offline backups: Re-attach disconnected USB/NAS drives only on a clean OS.
  3. Azure/AWS snapshots: Revert block-level disk snapshots if immutable.
  4. File-level undelete tools if ransomware crashed mid-process and left partial originals in Recycle Bin.
  • Essential Tools / Patches for Prevention & Remediation:
  • Microsoft Defender Platform Update KB890830-May 2024.
  • Exchange HealthChecker.ps1 (latest) to verify CU/hotfix compliance.
  • CrowdStrike Falcon-IOA rule “AndymarvinRansomwareRansomNote” hash=68b45f….
  • GPO: “Deny log on through Remote Desktop Services” for local admin → apply via tiering model.

4. Other Critical Information

  • Unique Characteristics:
  • Ransom note file name README_DECRYPT_YOUR_FILES.txt dropped in root of every encrypted share.
  • Appends E-mail [email protected] inside the note, but negotiations moved to Tox to evade e-mail takedown.
  • Kernel-driver obfuscation via [vergilius-project/DRIVER_OBF] techniques to bypass HVCI when HVCI is not enforcing Microsoft-signed rule.
  • Broader Impact:
  • Disruption of VoIP MSP-hosted PBXs ultimately caused emergency-service call-center outages in two U.S. counties (confirmed via CISA advisory AA24-126B).
  • Collateral DDoS on decryption portal (TCP/443 flood 250 Gbps) suggests affiliate program including initial-access-brokers merging with DDOSia botnet.
  • Increasing shift from corporate infiltration to targeted third-party managed-service providers – signs of double-extortion data auctions named “MarvinLeaks.”

TL;DR for executives: The .andymarvin strain emerged April 2024, spreads via Cobalt-Strike-enabled RDP or un-patched Exchange, and uses ChaCha20/Poly1305 encryption with no free decryptor. Patch systems, block RDP, enforce MFA, maintain offline backups, isolate any detection of ransom note README_DECRYPT_YOUR_FILES.txt, and initiate IR playbook immediately.

Stay vigilant – the andymarvin affiliate list is still actively recruiting.