If You're Reachable, You're Breachable, Part 3: The Adversary's Final Move – Exploiting You

Over the part 1 and part 2 of this series, we have followed the adversary's journey. In Part 1, we saw how they use internet-wide scanners to find your exposed VPNs, Firewall and other digital assets. In Part 2, we detailed how they classify those assets, building a detailed blueprint of your security stack i.e. VPNs, Firewalls, and your application infrastructure.

Now, we arrive at the final, inevitable conclusion of this process. The reconnaissance is over. The blueprint is complete. This phase is the "breach" in "breachable." This is the exploitation phase.

From Knowledge to Action: Weaponizing Intelligence

The adversary now has a list of your exposed services like VPNs and Firewalls, and their exact versions. This is the ammunition. The next step is to find the weapon to fire it.

1. Finding the Exploit (The CVE Playbook)

The first stop is a public vulnerability database, like the National Vulnerability Database (NVD). The attacker takes the version number they discovered (e.g., Apache/2.4.49, VPN/Brand Name) and searches for any associated Common Vulnerabilities and Exposures (CVEs).

Instantly, they have a list of known weaknesses for that specific software. Each CVE comes with a description of the vulnerability, its severity score (CVSS), and often, links to proof-of-concept (PoC) code. The attacker isn't guessing; they are following a well-documented recipe for a breach.

2. Loading the Weapon (Exploit Frameworks like Metasploit)

For common vulnerabilities, an attacker doesn't even need to write code. They turn to powerful, open-source exploit frameworks. Think of these frameworks as a digital Swiss Army knife for penetration testers and, unfortunately, for criminals. It contains a vast library of pre-built "exploit modules"—scripts that are ready to fire at a vulnerable service.

The process is chillingly simple:

• Search these repositories or frameworks for the CVE number (e.g., CVE-2024-55591).
• Load the corresponding exploit module.
• Set the target IP address (which they already have).
• Type exploit

If successful, the framework establishes a "shell" or a "session" on your VPN or Firewall server, giving the attacker direct command-line control. They are now inside your network. It can be that easy.

AI: The Autonomous Attacker Is Here

If the commoditization of exploits wasn't bad enough, AI is now supercharging the entire exploitation process, enabling attacks at a scale and speed that is impossible for human defenders to counter.

• AI-Driven Exploit Customization: Standard exploits are often caught by security tools like Intrusion Detection Systems (IDS) or Web Application Firewalls (WAF). Adversaries are now using AI to generate polymorphic versions of their exploits. The AI can subtly alter the attack code for each attempt, creating an infinite number of variations that fly under the radar of signature-based defenses.
• Predictive Exploitation: An AI model can analyze the complete target profile—OS, services, patch level, detected security tools—and predict the single most effective exploit chain. It might determine that a frontal assault on the web server will be blocked, but a less-common vulnerability in an adjacent VPN has a higher chance of success and will lead directly to the internal database.
• Autonomous Kill Chains: The most advanced adversaries are using AI to automate the entire attack sequence. The AI finds a target, classifies its services, selects and launches the initial exploit, and then—once inside—begins moving laterally, escalating privileges, and exfiltrating data, all without direct human intervention. This compresses an attack that once took weeks or months into a matter of minutes.

Breaking the Chain: How to Make Yourself Un-breachable

Let’s recap the adversary's playbook: Find → Classify → Exploit.

Notice a pattern? Every single step depends on one fundamental prerequisite: your internal application must be invisible and unreachable on the public internet. If an attacker can't find you, they can't classify you. If they can't classify you, they can't exploit you.

Traditional security tried to solve this with better firewalls, WAFs, and VPNs—essentially, by building stronger doors and locks. But as we've seen, adversaries will always find a way to pick the lock or discover a window left open.

The only way to win is to change the game entirely. The solution is not a stronger door; it’s to remove the door from public view i.e. replace your VPNs and Firewalls.

The Zscaler Difference

This is the core principle behind the Zscaler Zero Trust Exchange.

Instead of exposing your applications to the internet and hoping your defenses hold, Zscaler makes your applications and internal resources completely invisible. The Zero Trust Exchange operates as an intelligent, inline switchboard that checks identity, device posture and business policies before connecting the right party (user, application, etc.) to the right party. Here's how:

1. No Inbound Connections: Your applications, code repositories etc., whether in the data center or a public cloud, never accept inbound connections. They are not listening on the internet. They have no IP addresses that can be discovered or scanned by any tools. Your attack surface is not just minimized—it's eliminated.
2. Inside-Out Connectivity: To make services available, a lightweight Zscaler connector, sitting with your applications, establishes an inside-out connection to the Zscaler cloud. This connection is outbound only, so no inbound firewall rules are ever needed.
3. Brokered Access: When an authorized user—authenticated and policy-checked by Zscaler—needs to access an application, the Zero Trust Exchange securely stitches the two outbound connections together. The user connects to the application through Zscaler; they never connect to the application directly. Secure, brokered connections are built on a session-by-session basis, following the principles of least privilege access, and continuously assessed for changes in risk.

An adversary scanning the internet sees nothing. There is no VPN to find, no Firewall port to scan, no banner to grab, and no vulnerability to exploit. Your organization is off the public map. Your existing VPNs and Firewalls are not the answer as they are built on an architecture that exposes them to the Internet and hence to the attackers. Your security stack needs to protect you, not expose you. Hence, you should look at replacing your existing VPNs and Firewalls, with a solution that enables you to stay invisible and reduces your attack surface.

You can't be reachable, because you're not there. And if you're not reachable, you can't be breached. It's that simple.

For a summary and a visual representation, please see this video.