Zero-Day Attack Vectors: A Complete Guide

Ever had a cyber attack that you did not see coming? Zero-day attacks exploit unidentified vulnerabilities in your systems, rendering you helpless. Zero-day exploits do not signal themselves like other traditional threats do. They appear with no notice at all, and security teams will have zero seconds to patch and prepare. You will have lost data, suffered operational interruption, and lost reputation when these stealthy bugs are exploited. You can shield your organization from being vulnerable to such unseen attacks by learning about attack vectors, proactively employing security measures, and having a ready response. If you need to protect yourself against such invisible attacks, learn to detect, minimize, and react to zero-day attacks before disaster hits.

We will explain zero-day attacks for you, break them down, and cover how to deal with zero-day attack exploits too.

What Is a Zero-Day Attack?

What are zero-day attacks? They are attacks carried out by operators who have various sets of motives. Some are driven by financial gains while others have personal agenda They may be bitter about the organization and want to tarnish its reputation. Hacktivists launch zero-day exploits and take advantage of them because they want to draw attention to their causes. Zero-day threats are a great way to gain high visibility among the masses. Corporate espionage can be seen as a way to gain competitive intelligence. State-sponsored actors and governments may also launch zero-day attacks and see them as a tool to wage cyber warfare against other countries and states.

Impact of Zero-Day Attacks on Organizations

Here is a list of the impacts of zero-day attacks on organizations:

• Delayed Discovery Results in Long Risk Windows: The time it takes for systems to be initially exposed and vulnerabilities discovered can be months. During this period, attackers can secretly operate while organizations are blissfully unaware they are compromised.
• Backdoor System Access and Operations Disruption: Zero-day attacks allow intruders to create persistent backdoors and vulnerable access points into the system. This unauthorized access can disrupt mission-critical business operations and lead to long-term security breaches.
• Financial and Reputation Loss: Firms lose money directly through zero-day attacks and suffer heavy reputation loss when attacked. Customer trust, which can be lost as a result of theft of sensitive data, is recovered in years.
• Data Exfiltration and Privacy Violations: Zero-days are employed by criminals to exfiltrate sensitive data from compromised systems. This violates user privacy as well as the organizational data asset integrity, with a potential violation of regulatory requirements.
• Weaponization for Cyber Warfare: Government-sponsored groups and malicious actors use zero-day vulnerabilities as weapons for espionage and cyber warfare. Such attacks can hit significant infrastructure with resultant heavy disruption or even physical damage.
• Evasion of Traditional Security Tools: Zero-days are “unknown unknowns” that will likely evade traditional security tools based on signature-based detection. This built-in detection gap creates humongous security blind spots.
• Enforcing Reactive Security Postures: Since zero-days by definition are unexpected, they put the security team in a reactive position instead of a proactive one. This gives the attacker a tremendous strategic advantage at the start of the exploit process.
• Dormant Threat Actors Within Systems: Attackers who enter through zero-days can become dormant within systems for extended periods of time, achieving persistence before executing bigger attacks. This complicates detection and remediation significantly.
• Increased Frequency and Severity of Attacks: With every new zero-day found, attacks become more intense and frequent. This also makes the security environment more hostile for organizations.
• Reducing Windows of Response: As attacks become more sophisticated, detection and response windows for businesses narrow to hours or minutes, requiring faster automated defense and intelligence capability.
• Black Market Exploit Trade: Black markets are created by the costly nature of zero-days with such exploits being traded. The economic incentive drives vulnerability finds off responsible disclosure channels to malicious exploitation.

Why Are Zero-Day Attacks Dangerous?

The scary part about zero-day attacks is that you don’t know the window of vulnerability. You don’t know exactly what you’re working with or what hits. And the worst part is you don’t know how long that period of vulnerability will last until the software developer eventually releases a patch or finds a solution for it. The clock is ticking and you don’t know how much time you have. So the scope of damage is unknown. The adversary gets complete access to your systems and resources and they can keep breaching until it’s too late.

In some cases, they might even dismantle your business operations and discontinue services. You won’t have a chance to even recover against some of these threats. The downtime can be permanent, which is what makes it so scary. By the time you fix the zero-day exploit, the damage has already been done. For unknown vulnerabilities, it’s much harder for vendors to cover up and provide insurance to clients. By the time vendors are aware of the zero-day vulnerability, attackers would have already gotten into the network and exploited flaws. That means users stayed unprotected. You don’t know what the attacker knows and that’s what makes the zero-day attack so dangerous. It’s called a zero-day vulnerability because you get zero days to remediate it.

Common Zero-Day Attack Vectors

Here is a list of the most common zero-day attack vectors:

• Web Application Vulnerabilities: You are exposed to attack through unpatched content management systems, custom web applications, or API endpoints. Attackers exploit input validation vulnerabilities, injection flaws, or broken authentication to initially gain access to your systems.
• Unpatched Operating Systems: Holding off on updating systems leaves your organization vulnerable to kernel-level attacks. These provide privilege escalation and lateral movement on your network.
• Document Exploits: Keep an eye out for PDFs, Office documents, and other attachments. They may contain malicious code directed at application parsers and viewers that execute upon opening.
• Browser Vulnerabilities: You will be vulnerable to attacks by compromised sites that have browser exploits. These bypass sandbox protection and execute arbitrary code on visitor machines without any intervention from the user.
• Supply Chain Compromises: Third-party software and components within your supply chain can bring vulnerabilities with them. Attackers target these upstream dependencies in order to infect numerous victims simultaneously.
• IoT Device Vulnerabilities: When you use internet-connected devices with few security controls, you will be leaving more attack surfaces open. Firmware vulnerabilities and hardcoded credentials allow the attacker to pivot into your main network.
• Memory Corruption Vulnerabilities: Buffer overflows, use-after-free, and heap manipulation vulnerabilities provide attackers with control of program execution flow, enabling code injection or execution.
• Protocol Implementation Weaknesses: You may be vulnerable through network devices using protocols with implementation flaws in TLS, DNS, or other communication protocols.

How Zero-Day Vulnerabilities Work?

A zero-day vulnerability is a hidden weakness in an organization’s software build. There can also be loopholes found in user accounts that can be exploited. Think of it like a bug for which no fix has been made yet. The developers aren’t aware of the bug but the hacker finds and exploits it. It can be a defeat in the software’s code or any opportunity in the network that could grant them unauthorized access.

The attacker will build off the vulnerability and try to propagate it. Maybe they will create new vulnerabilities or hijack the system by carrying out specific actions. The point is, it’s a way of malicious entry into the organizations. Once they are in, they can steal data, control other systems and resources remotely, and execute malicious code in the background. They can stay hidden and attack whenever they want. Zero-day prevention begins with the awareness of how these zero-day exploits work.

Detecting Zero-Day Attacks

There are several ways you can detect zero-day attacks:

• Ethical hackers can use a series of penetration tests to scope for security flaws before the dark hats can find them. They can simulate attacks on systems and probe for existing vulnerabilities. Penetration tests will thoroughly test your organization’s security posture. They will use a mix of tools  and assessments to check the systems’ resilience.
• Bug bounty programs identify and report findings about zero-day vulnerabilities and help too. Companies these days are offering monetary rewards in exchange for providing comprehensive zero-day vulnerability reports. You can hire bug bounty bounters and take their expertise anytime to find hidden and unknown zero-days. However, keep in mind that they follow strict disclosure guidelines to report their findings and stay private.
• Static and dynamic code analysis can be used for zero-day detection and mitigation. This is where you examine the code syntax, structure, and semantics carefully. There are various tools you can use like SentinelOne to perform it. Common security flaws you will look for are SQL injection points, buffer overflows, and unsafe coding practices. Dynamic code analysis targets looking for malicious code and effects after software execution. It will study your program’s behavior in real-time and identify security issues when your programs run. Dynamic code analysis is ideal for detecting runtime zero-day exploits and checks for flaws that arise when your apps interact with others across different environments.
• Sharing threat intelligence is another excellent way to identify zero-day vulnerabilities. It can help assess potential risks and provide additional insights. You end up learning about the latest tactics and techniques used by adversaries to breach your organizations’ defenses. You can collaborate with threat intelligence platforms and cybersecurity companies to safeguard your future and work on your new security strategy. The collective knowledge helps in coming up with the best patches, countermeasures, and other defenses to reduce the window of exposures.

Mitigating Zero-Day Exploits

To mitigate zero-day exploits, organizations should take steps to prevent them. The best line of the defense is the measures you set up. An attacker is less likely to breach when your security defenses are robust. Here are some recommended courses of action effective zero-day exploit prevention:

Disable HTTP servers – Organizations can reduce attack surfaces and prevent unauthorized access. They must promptly disable HTTP servers. Cisco has made a list of IoCs after their reach to help businesses watch out for common vulnerabilities. They can refer to that list for early detection and threat isolation.

Build a Zero Trust Network Architecture (ZTNA) – It’s also equally important to build a Zero Trust Network Architecture (ZTNA) and enforce robust authentication mechanisms. Organizations should implement multi-factor authentication and add additional layers of security. In the event their credentials get stolen by adversaries, they will be better protected. With MFA turned on, attackers can’t get deeper access to sensitive resources.

Responding to Zero-Day Threats

For a zero-day attack, you have to segregate infected systems as soon as possible in order to limit the breach. Isolate affected systems from the network but maintain evidence for forensic analysis. You can roll out stopgap measures like network filtering, application whitelisting, or feature disabling to block attack vectors until patches become available. If you have to assess damage, conduct swift triage to identify affected data, affected users, and business impact. You will need to prioritize important assets for recovery processes.

You must search for indications of compromise across your environment to find attack persistence. There will be indications of unusual network activity, unusual system activity, or unusual account activity. You will have to report openly to stakeholders regarding the incident, response to be taken, and security advice. But you will have to comply with reporting data breach legislation applicable. Whenever patches are made, you can bring them in phases via an emergency change process, checking fixes before mass deploying them.

Real-World Examples of Zero-Day Attacks

Cisco presented new zero-day vulnerabilities on their devices that used iOS XE software. Devices were exploited locally on networks, and targeted ones were exposed on the web. Attackers made accounts with the highest privileges and completely controlled infected devices. Patching was needed to take care of outages, but they were too late, based on system specifics.

The Apache Log4j vulnerability in December 2021 is another zero-day vulnerability case study. It shocked the Java security community. No patch, fix, or update was available for it. Governments, corporations, and other agencies were all hit by it.

How Can SentintelOne Help?

If you think your organization is at risk of zero-day exploits or suspect something is happening but can’t pinpoint it, a solution like SentinelOne can be a critical part of your cyber defenses. Its External Attack and Surface Management tools, included in its agentless CNAPP and comprehensive vulnerability assessments, can help you identify the latest security weaknesses.

SentinelOne can work as an IoT security and observability platform. You get continuous AI threat detection in real-time with runtime security.  SentinelOne’s Offensive Security Engine can help you fight against known and unknown threats. Purple AI, its Gen AI cybersecurity analyst, can provide additional security insights about your tools, users, and devices. SentinelOne gets your organization compliance-ready and prevents policy violations by adhering to the best regulatory frameworks like ISO 27001, SOC 2, NIST, CIS Benchmark, etc. Its global threat intelligence can extract and analyze data from multiple sources for further analysis, building off of what’s available online. SentinelOne’s platform can not only fight against zero-day exploits, but also provides active defenses against spyware, ransomware, malware, phishing, social engineering, and all other forms of cyber threats. Its Cloud Workload Protection Platform can help secure your VMs, containers, and other services. For organizations that want to extend their endpoint defenses, the SentinelOne Singularity XDR Platform will help. Book a free live demo.

Conclusion

Zero-day attacks are a constant threat to your digital assets, exploiting yet-to-be-known vulnerabilities before patches. You can minimize your attack surface by tight management of patches, implementing defense-in-depth tactics, and using behavior-based detection technologies. By investing in threat intelligence collaboration and security awareness, you will gain valuable time advantages against these stealthy threats. You need to develop incident response playbooks for the particular purpose of zero-day scenarios and practice them regularly in tabletop exercises.

There will always be unknown vulnerabilities, but with multiple layers of protection and the capability to respond rapidly, you can significantly minimize potential damage when zero-day exploits inevitably occur. Contact SentinelOne for assistance.