Initial Access is the first phase in the MITRE ATT&CK framework where a threat actor attempts to gain a foothold in a target environment.
This phase focuses on how attackers enter a network, system, or cloud environment—often by exploiting vulnerabilities, manipulating users, or abusing legitimate access methods.

Think of it as the “break-in” stage before any deeper malicious actions occur (e.g., execution, persistence, privilege escalation, etc.).

🔍 Why Initial Access Matters

It reveals common entry points used by attackers.
Helps organizations strengthen defenses by closing vulnerable pathways.
Supports incident responders in identifying how a breach started.

🛠️ Main Techniques Under Initial Access (Clear Explanation)

1. Phishing (T1566)

Attackers send deceptive emails or messages to trick users into performing actions like clicking malicious links or opening harmful attachments.

Often leads to malware infection or credential theft.

2. Drive-by Compromise (T1189)

A user unknowingly gets compromised by visiting a website that automatically executes malicious code due to browser/plugin vulnerabilities.

3. Exploit Public-Facing Application (T1190)

Attackers take advantage of vulnerabilities in internet-facing applications (e.g., web servers, APIs) to gain unauthorized access.

4. Supply Chain Compromise (T1195)

Malicious actors infiltrate through a trusted partner, software vendor, or third-party dependency.

Example: installing malware in a software update package.

5. Valid Accounts (T1078)

Using legitimate credentials—either stolen or purchased—to log directly into the system.

Can bypass many security alerts because access appears normal.

6. Hardware Additions (T1200)

Attackers introduce malicious hardware devices (e.g., infected USB sticks, rogue Wi-Fi access points) to gain entry.

7. Trusted Relationship (T1199)

Abusing pre-established connections between organizations or systems.

Example: breaching a managed service provider (MSP) to reach its clients.

8. External Remote Services (T1133)

Logging in through remote access services like VPN, RDP, SSH using valid or brute-forced credentials.

9. Replication Through Removable Media (T1091)

Malware spreads via removable media like USB drives—popular among espionage-focused threat actors.

10. Internet-Facing Remote Services (subset of T1133 variations)

Targeting exposed remote access points such as Citrix, VNC, or cloud admin portals.

MITRE Initial Access: How Cyber Attacks Begin