What is a Zero Day exploit?

If you have been watching the Netflix mini-series Zero Day and are still unsure what a zero-day exploit or attack is...then we may be able to help...

A zero-day exploit is a cyberattack that takes advantage of a software vulnerability that is unknown to the software maker and the public. Since no patch or fix exists yet, hackers can use it to compromise systems before anyone even knows about the flaw - hence the term zero-day (meaning zero days of protection).

How It Works:

1. A hacker (or researcher) discovers a flaw in software, an app, or even hardware.

2. If malicious hackers find it first, they can create an exploit—code that takes advantage of the flaw to break in.

3. Since no fix exists yet, attackers use it to steal data, disrupt services, or spy on users.

4. Once the software vendor (like Microsoft, Apple, or Google) learns about it, they scramble to release a security patch.

5. Meanwhile, cybercriminals or nation-state hackers might use it in targeted attacks, often on high-value targets like governments or big companies.

Why It's a Big Deal:

• No defense exists initially. Since the software maker doesn’t know about the flaw, users are vulnerable.

• Used in cyber warfare & espionage. Governments and hacking groups often use zero-day exploits to spy or attack infrastructure.

• Can be extremely valuable. Some zero-days sell for millions of dollars in underground markets or through "bug bounty" programs.

Real-World Examples:

• Stuxnet (2010): A cyberweapon used to sabotage Iran’s nuclear program, exploiting multiple zero-day vulnerabilities.

• Pegasus spyware: Used to hack phones of journalists, activists, and politicians worldwide.

• Log4j (2021): A critical zero-day exploit in a widely used software library, affecting millions of systems.

If the show zero day focuses on cyberattacks or national security threats, it might be exploring

how these vulnerabilities can be used for large-scale disruptions.

How Zero-Day Exploits Are Discovered and Stopped

1. How They Are Discovered

Zero-day vulnerabilities can be found by different groups, each with their own motives:

• Ethical Hackers & Security Researchers:

• White-hat hackers work for cyber security firms or "bug bounty" programs (like those run by Google, Microsoft, or Apple).

• They analyse software, test for weaknesses, and report vulnerabilities responsibly before they can be exploited.

• Malicious Hackers & Cybercriminals:

• Black-hat hackers actively look for unknown weaknesses to exploit systems.

• Some sell these exploits on the dark web to the highest bidder.

• Government & Intelligence Agencies:

• Some zero-days are discovered (or even secretly developed) by intelligence agencies for cyber-espionage or warfare.

• Example: The NSA allegedly discovered and used a Windows zero-day exploit before it was leaked and used by cybercriminals (WannaCry ransomware attack).

• Automated Scanning Tools & AI:

• Some cyber security companies use AI-driven tools to scan software and networks for unusual behavior that might indicate a zero-day vulnerability.

2. How They Are Stopped

• Patch Deployment:

• Once a zero-day is reported, the software company rushes to develop a patch (a security update) to fix the flaw.

• Example: If a zero-day is found in Windows, Microsoft releases an emergency security update through Windows Update.

• Intrusion Detection Systems (IDS) & AI-Based Security:

• Since patches take time, cyber security tools use behavior-based detection to spot unusual activity (e.g., unauthorised access, data leaks).

• Example: AI-driven security platforms like CrowdStrike or Palo Alto Networks use machine learning to detect zero-day attacks in real time.

• Threat Intelligence & Security Teams:

• Cyber security teams in big companies continuously monitor attack patterns and collaborate with global networks to detect and share information on zero-day threats.

• Organisations like CISA (Cyber security & Infrastructure Security Agency) issue alerts about new threats.

• Zero Trust Security Model:

• Instead of assuming everything inside a network is safe, companies now use zero trust—meaning every request is verified before access is granted, reducing the damage from unknown vulnerabilities.

Why Fixing Zero-Days Is So Hard

• The time between discovering a zero-day and patching it is called the patch gap - this is when hackers exploit it the most.

• Some patches break other parts of the software, so companies need time to test them.

• If users don’t update their software quickly, they remain vulnerable.

💡 Pro Tip: Always keep your software and operating system updated! Many zero-day exploits target outdated systems.

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Reporting

Report all Fraud and Cybercrime to Action Fraud by calling 0300 123 2040 or online. Forward suspicious emails to report@phishing.gov.uk. Report SMS scams by forwarding the original message to 7726 (spells SPAM on the keypad).

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