🔍 Why Initial Access Matters Most

Most ransomware attacks don’t start with malware—they start with a foothold. Phishing, exposed services, and vulnerable software supply chains remain the top vectors for ransomware deployment. The earlier you can stop access, the less you need to recover from.

This post walks through practical defenses for blocking ransomware at its most vulnerable phase: before it enters your network.

📧 Phishing: Still the #1 Entry Point

Ransomware operators rely on phishing to deliver payloads or steal credentials:

• Office document macros (still alive via legacy support)
• Fake MFA push fatigue prompts and credential capture sites
• Links to drive-by downloads or cloud-hosted malware (e.g., Google Drive, Dropbox)

Defenses:

• Advanced phishing protection (e.g., Proofpoint, Microsoft Defender, Mimecast)
• Disable macro execution by default; implement Protected View and blocking policies via GPO
• Implement phishing-resistant MFA (FIDO2/WebAuthn preferred)

🖥️ RDP: A Persistent Risk in Hybrid Environments

Remote Desktop Protocol (RDP) remains a high-value target due to:

• Weak or reused passwords
• Lack of MFA
• Direct exposure to the internet

Defenses:

• Block RDP from the public internet via firewall or VPN enforcement
• Enable account lockout thresholds and monitoring (e.g., failed logins via Event ID 4625)
• Enforce MFA for all remote access—even via VPN
• Use Just-In-Time (JIT) access or Privileged Access Management (PAM) tools

🏗️ Software Supply Chain: Hidden in Your Dependencies

Attackers increasingly target third-party software and build pipelines:

• Compromised updates (e.g., Kaseya, SolarWinds)
• Malicious open-source packages (typosquatting or dependency confusion)
• CI/CD credential leakage or pipeline hijack

Defenses:

• Use Software Bill of Materials (SBOM) to inventory dependencies
• Pin dependency versions and use trusted package sources (e.g., private PyPI, npm registries)
• Segment build environments from the internet and monitor CI/CD behavior
• Scan builds for known vulnerabilities and malware using tools like Snyk, Trivy, or Aqua

🔑 Credential Abuse and Identity Protection

Even when malware isn’t involved, valid credentials often are:

• Harvested via phishing or infostealers
• Purchased from credential dumps or initial access brokers

Defenses:

• Implement MFA for all external access and privilege elevation
• Monitor for anomalous logins across geos, devices, and times
• Use conditional access policies to block logins from risky locations

🛡️ Defense in Depth: Don’t Rely on a Single Control

No single layer will stop every attack. Combine:

• Email filtering + URL rewriting + attachment sandboxing
• MFA + conditional access + PAM
• Vulnerability management + patching SLAs
• Network segmentation + firewall rules for exposed ports

Even if a phishing attempt succeeds, strong identity and endpoint hygiene can stop escalation.

📣 Final Thought

Preventing ransomware starts with preventing access. Focus on exposure reduction, identity security, and email resilience—because once the attacker is inside, your options shrink fast.

Need help assessing your ransomware exposure or testing external access defenses? Let’s talk.