External Threats vs. Internal Threats in Cybersecurity

External Threats vs. Internal Threats in Cybersecurity
6 minute read

A comprehensive security strategy consists of two parts: internal threat defense and external threat defense. While it is important to know the difference, total defense-in-depth requires both key players. Building out that well-rounded approach requires an overall understanding of the nature of both strategies, how they diverge, and how to balance both in a zero-trust-centered security architecture.

External Threats

External threats are risks that originate outside the network, taking in public-facing forums and world events. Hence, external cybersecurity can be defined as, “the orchestration of humans and machine intelligence to discover and disrupt threats beyond the corporate perimeter.” We all know there is no such thing as a security perimeter anymore, but the corporate enterprise has its bounds. Beyond those lie risks to data, people, domains, apps, and the brand at large. These risks are lurking on malicious domains, in social media apps, and on the open web, in emails as phishing attempts, and as attack chatter on the Deep and Dark Web, to name a few vectors. The perpetrators? Hacktivists, cybercriminals, nation-states, and geo-political dissidents. The list goes on.

Do you see how hard it would be to “catch” all these threats with traditional enterprise-bound tools? An XDR tool, for all its power and use, cannot search back-alley channels of Tor to proactively scope out percolating danger. SIEMS and firewalls, and SOAR tools cannot reach LinkedIn and remove sensitive data that’s been posted by an unwitting employee or protect an executive’s account from being impersonated. And yet those threats are out there, and someone has to account for them. Saying your security tools don’t reach far enough may be true, but it won’t be any consolation when your organization falls prey to an external blind-spot attack.

Internal Threats

Internal threats, on the other hand, are what we are used to. They are what most typically think of when we define cyber threats at large, and usually don’t extend beyond the “perimeter”. This means that they originate in or primarily take place within the corporate enterprise, and can be detected, investigated, and blocked there.

Internal threats include ransomware and malware threats, C2 commands, viruses and exploited vulnerabilities, cross-site scripting exploits, and signature-based threats. They can also be part of broader schemes of cybercriminal science and require AI-driven solutions to ferret them out. The differentiating factor is the fact that they are found and fought by enterprise security tools within the bounds of the company’s digital ecosystem.

Differences between External and Internal Threats

External and internal threats not only differ in type and origin, but in methods, motives, and risks. 

External threats are perpetrated in “the digital environment beyond your perimeter where digital innovation happens, customers engage, and threat actors lurk.” They happen via brand impersonation (by anyone from domain squatters to nation-state actors), executive impersonation (when a C-level gets spoofed), illegitimate apps carrying malware, fake job postings, DDoS attacks planned in the Underground Economy, and more. Bad actors behind these crimes are often social engineering experts and can be spurred on by a variety of motives: personal or social issues that would lead them to ruin a brand (hacktivists), political leanings (nation-state actors), or financial gain (job board spoofers). Unfortunately, they create a unique flavor of risk for the companies they target: brand and reputational damage, monetary loss, and even physical harm.

Internal threats often involve more sophisticated attack methods and are motivated mainly by material gain. A criminal hacking organization might release a never-before-seen advanced exploit that travels through a company’s software supply chain (NotPetya anyone?), perform a cross-site-scripting or man-in-the-middle attack, attempt to leverage expired certificates to gain entry into a system, or otherwise infiltrate network bounds and try to achieve root access. The goal can be data exfiltration (for the purpose of data sale), network disruption (often the work of nation-state actors), a ransom payment (ranging up to $40M), or infamy (as hacking groups try to ‘make it big’ with Colonial Pipeline-scale headlines).  

Both threats are critical and should be taken seriously. Together, they are two halves of the kind of holistic cybersecurity approach that is simply necessary in today’s threat environment. Companies face risks from all sides – sophisticated cybercriminals trying to sneak emerging exploits in and encrypt databases at the level of the kernel, and Dark Web-based baddies planning new ways to DDoS a water utility or take over the Twitter account of a Fortune 500 CEO. Either way, it’s bad news.

Balancing External and Internal Threat Protection

It makes no sense to lock the front door while leaving the back wide open. Similarly, securing an enterprise with state-of-the-art, AI-driven technology and failing to guard the company’s online presence only blocks some threats while inviting others. Both can incur costs any company would be unwilling to bear.

Achieving balance between the two sides means finding the resources that will do the job best, on both sides. This could mean an in-house XDR solution for combatting internal threats. This could mean an outsourced SOC. This could mean a range of disparate, ad-hoc external security solutions (the current status quo), or this could mean a managed external security provider.

As we stated in a previous blog, external cybersecurity is not “a replacement for firewalls, endpoint detection and response solutions (EDR), cloud access security brokers (CASB), etc.” Instead, the value add it can bring to the table is knowing when your records have been breached (and are being sold) on the Dark Web, and whether underground attack planning is taking place against your enterprise. You don’t have to be high-profile to be the subject of attack: external bad actors often target utilities, celebrities, or anyone they think can influence others to give away information or spend money in a ruse.

Keep internal controls while adding external security measures on top of an existing strategy. Don’t lessen defenses inside but do increase them outside. A balanced approach to cybersecurity starts where you are and builds, which is why companies should see if they have the resources for an external threat team – and if not, contact an external cybersecurity provider that can navigate the waters for them.

When done right, both internal and external security components lead to each other. Internal tools collect valuable data that is then synthesized by external cybersecurity models and used to build threat profiles on possible wrongdoers. External security solutions add additional insight and context to what might otherwise seem like a host of unrelated threats. External cybersecurity can also detect insider threats selling IP or remote access.

Used in tandem, external and internal security measures can disrupt potential threats before they get to your network – no matter where they’re from.


While different in nature and scope, external and internal threat detection methods provide a crucial combination for a winning cybersecurity approach. 

Internal threats do most of their damage within the inner workings of the network, and external cybersecurity covers threats that lurk in the greater digital (and often physical) world. Often, when a cybercriminal can’t get in one way, they’ll use the other. 

That’s why it’s so key to maintain a security strategy that regularly maintains and invests in best-in-class solutions for both, and leverages the expertise needed to run both sides with facility. 

ZeroFox is the leader in external cybersecurity, with inroads into the Underground Economy and years of experience in digital takedowns. From removing and debunking online impersonations and account takeovers to providing best-in-class brand protection, domain protection, social media protection, Dark Web monitoring, and a lot more, we’ve got the know-how to make sure your security strategy secures against threats on all fronts.

Want to learn more? See why ZeroFox is the unrivaled leader in external cybersecurity.

Tags: CybersecurityExternal Cybersecurity

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