Certified: The Security+ Prepcast

In this episode, we are exploring three critical sources of cyber risk that are often overlooked until they are exploited: open service ports, default credentials, and vulnerabilities within the supply chain. These issues are common, and attackers frequently scan for them across the internet. Identifying and correcting these weaknesses is one of the most effective ways to reduce the overall attack surface of an organization.
Let’s begin with open service ports. These are network ports that are actively listening for incoming connections. Every open port represents a potential entry point for an attacker. Common services that use open ports include web servers, file transfer systems, and remote desktop connections. While many open ports are necessary for business operations, unmanaged or unnecessary ports can expose systems to attack.
Attackers use automated scanning tools to search the internet for open ports. Once found, they probe the services running behind those ports, looking for vulnerabilities to exploit. If the service is outdated, misconfigured, or lacks proper authentication, the attacker can use it to gain unauthorized access or move further into the network.
A real-world example involved a database left exposed on an open port without a password. Attackers found it within hours, stole the data, and posted it online. The breach affected thousands of users and led to major reputational damage for the organization.
To secure open ports, organizations should perform regular network scans to identify which ports are active and what services are running behind them. Ports that are not actively used should be closed. Firewalls should be configured to restrict access to sensitive services. Whenever possible, remote access should be limited to known IP addresses or protected by virtual private networks and multifactor authentication.
Now let’s turn to default credentials. Many devices and applications come with default usernames and passwords like “admin” and “password.” These are meant to be changed upon installation, but often they are not. Default credentials are widely known and easily exploited by attackers.
Leaving default credentials in place is like locking your doors but leaving the key in plain sight. Attackers routinely scan for devices that still use these defaults. Once they gain access, they may install malware, exfiltrate data, or use the compromised system to launch additional attacks.
To mitigate this risk, organizations should audit all devices and systems upon deployment and change all default passwords immediately. This includes routers, printers, industrial control systems, and software platforms. Password policies should require strong, unique credentials and enforce periodic rotation. Credential management tools can help administrators securely track and update passwords across large environments.
A high-profile example of this threat involved a massive botnet attack that targeted internet-connected cameras and routers. Many of these devices had default credentials that had never been changed. The attackers used those credentials to take control of the devices and launch one of the largest distributed denial of service attacks ever recorded.
Finally, let’s examine supply chain threats. In cybersecurity, the supply chain includes all third-party organizations that support your systems—vendors, software providers, hardware manufacturers, and managed service providers. While these partners can help your organization run more efficiently, they also introduce risk. If one of them is compromised, it can create a backdoor into your environment.
Attackers know this and often target the supply chain as a way to bypass strong perimeter defenses. By compromising software updates, shared credentials, or third-party network connections, they can silently gain access to critical systems. This tactic is especially effective when the trusted partner has administrative privileges or is used for regular maintenance.
One of the most well-known examples of a supply chain attack occurred when a software provider was compromised, and malicious code was added to a routine update. When customers installed the update, they unknowingly invited the attacker into their systems. This single point of failure affected thousands of organizations and required months of investigation and cleanup.
To defend against supply chain threats, organizations should establish strong vendor management practices. This includes performing risk assessments before onboarding new partners, limiting third-party access to the minimum necessary, and continuously monitoring the activities of external users and systems. Contracts should require vendors to meet security standards, and incident response plans should include procedures for dealing with third-party breaches.
Ongoing audits, access reviews, and network segmentation can further reduce the blast radius if a supply chain partner is compromised. Security monitoring tools should be configured to alert on unusual behavior from vendor accounts or systems.
As you prepare for the Security Plus exam, make sure you can identify the risks and solutions associated with open service ports, default credentials, and supply chain access. Know how to audit your systems for exposed ports, why default logins are dangerous, and what steps to take when working with vendors and managed service providers. The exam may describe a breach scenario involving one of these vulnerabilities and ask you to determine how it occurred and how to prevent it in the future.