Software developers regularly explore for undiscovered flaws and, when they do, release a code fix (also known as a “patch”) to address them. A software weakness, on the other hand, that has not yet been identified by the vendor is known as a zero-day attack.


A Zero-Day Attack: What Is It?


A software vulnerability that is exploited by attackers before the vendor is made aware of it is known as a zero-day (or 0-day) attack. As there is currently no patch available, attackers can easily take advantage of the flaw since there are no safeguards in place. As a result, zero-day vulnerabilities pose a serious security risk.

After an attacker discovers a zero-day vulnerability, they require a delivery method to compromise the system. A socially engineered email or other message, which appears to be from a trusted or legitimate correspondent but is actually from an attacker, is frequently used as the delivery method. The message aims to persuade the user to take a specific action, such as opening a file or going to a malicious website, which will unintentionally activate the exploit.


What Are Zero-Day Exploits and Why Are They Dangerous?


An attack on a system using a zero-day vulnerability is known as a zero-day exploit. These exploits are particularly risky since they have a higher chance of success than assaults on known flaws. When a vulnerability is made public on day zero, businesses do not yet have time to patch it, which makes an attack conceivable.

The fact that certain sophisticated cybercriminal organisations deploy zero-day exploits strategically makes them much riskier. Some firms save zero-day exploits for high-value targets including government agencies, financial institutions, and healthcare facilities. This can lengthen the duration of the attack and decrease the likelihood that the victim will find a vulnerability.


A common zero-day attack goes like this:

1. Attackers look through the code or experiment with well-known programs in search of vulnerabilities. Moreover, they could purchase weaknesses on the black market.

2. Attackers write exploit code, such as malicious software or other technical tools, to take advantage of the vulnerability.

3. Attackers can employ automated scanners, bots, and other techniques to find systems that are vulnerable by searching for systems that are affected by the vulnerability.

4. Preparing the attack: Before launching a targeted attack against a particular company, attackers may conduct extensive reconnaissance to determine the best technique to compromise the weak point in the system. Attackers generally utilize bots or extensive phishing operations in non-targeted attacks to try to access as many weak systems as they can.

5. An attacker enters through the perimeter defenses of an organization or personal device.

6. Launch of a zero-day exploit now allows attackers to remotely execute code on the infected machine.


Attackers can fall into a number of groups depending on how they plan and execute zero-day attacks:

  • Cybercriminals– are hackers whose main motivation is frequently monetary.
  • Hacktivists-assailants driven by an ideology—typically want their attacks to be widely prominent so that others will support them in their cause.
  • Corporate espionage-attackers that want to steal confidential information from other companies.
  • Cyberwarfare-in recent years, nation states and national security agencies have frequently used cyberthreats against the infrastructure of other countries or critical infrastructure groups within those countries.


The Difference Between Targeted and Non-Targeted Zero-Day Attacks


Targeted zero-day attacks are carried out against high-profile targets, including senior personnel who have privileged access to company systems, access to sensitive data, intellectual property, or financial assets, huge corporations, and government or public institutions.

Non-targeted zero-day attacks often target numerous residential or commercial users who make use of a weak system, like an operating system or browser. The attacker’s objective is frequently to hack these computers and utilize them to create sizable botnets. Using the EternalBlue vulnerability in the Windows SMB file protocol, the WannaCry assault recently compromised over 200,000 devices in a single day. Hardware, firmware, and Internet of Things can all be the subject of untargeted attacks (IoT).


Zero-Day Attacks Examples:

1. Stuxnet

Stuxnet was referred to as the first cyberweapon in history. In 2006, Iran’s uranium enrichment centrifuges were breached using malware. The National Security Agency (NSA), according to several analysts, developed the zero-day exploit. A specialized industrial control system was compromised by Stuxnet, which then sped up or slowed down the centrifuges until they self-destructed. Iranian monitoring systems gave the impression that everything was running normally during this operation.


2. RSA

An unpatched flaw in Adobe Flash Player allowed attackers to enter the network of security provider RSA in 2011. Employees at RSA received emails from the attackers with Excel spreadsheet attachments that activated Flash files that took use of zero-day Flash vulnerabilities. Key data from SecurID security tokens used by RSA clients was among the stolen data.


3. Sony

A zero-day hack specifically targeted Sony Pictures in 2014. The attack brought down Sony’s network, and attackers leaked sensitive corporate data on file sharing websites, including private information about Sony employees and their families, internal correspondence, details about executive salaries, and copies of unreleased Sony movies, even though the specifics of the vulnerability exploited in the attack are still unknown. Several systems on Sony’s corporate network were deleted by attackers using a variation of the Shamoon wiper malware.



The Zero-Day Market

An advantageous asset is a zero-day vulnerability. It is important to attackers who can use it to their advantage and vulnerable to software suppliers who seek to safeguard their customers.

There are now three markets where both honest and dishonest researchers can exchange zero-day vulnerabilities and exploits:


  • White Hat Markets – There are a number of bounty programs where software developers and security firms would pay someone to find a brand-new, undiscovered vulnerability. GitHub and BugCrowd have started bounty programs, as have major technological companies like Apple, Microsoft, and Facebook, as well as governmental organizations like the Pentagon. If researchers are successful in identifying and documenting a security vulnerability, all of these offer researchers between hundreds and hundreds of thousands of dollars.


  • Zero-day feeds– Security research firms provide their clients with zero-day feeds, which contain details on undiscovered vulnerabilities but are kept confidential to preserve their usefulness.


  • Grey Hat Markets- There are zero-day brokers who hunt for solid zero-day research and purchase it on behalf of their clients while maintaining the confidentiality of the buyer and seller’s identities. While the vulnerability information may be provided to software vendors or other legitimate parties, in some cases it may be sold to a hostile foreign country, a terrorist organization, or a hacker group. The seller, who may be a legitimate researcher, has no control over what the end purchaser will do with the vulnerability information.


  • Black Markets– There is a booming underground market for exploits and zero-day vulnerabilities. Threat actors purchase vulnerabilities that hackers or unethical researchers have identified for sale with the intention of exploiting them in attacks against susceptible systems. Cybercriminals are increasingly producing and disseminating zero day information and vulnerabilities, according to researchers who keep an eye on these black marketplaces.


Zero Day Protection and Prevention


There are ways to prepare, even though zero-day assaults are challenging to fight against. To learn about four best practices that can shield you from zero-day attacks, see our guide on zero-day protection:

  • Windows Defender Exploit Guard– is a security tool included with Windows 2010 that contains a number of features that can successfully thwart zero-day attacks. When attacking Windows endpoints with zero-day exploits, it can act as a first line of defense.
  • Next-Generation Antivirus (NGAV)-traditional antivirus protection is typically ineffective against zero-day attacks because they take advantage of vulnerabilities in already-released software. However some zero-day attacks may be resistant to Next Generation Antivirus (NGAV) systems’ use of threat intelligence, behavioral analytics, machine learning code analysis, and other anti-exploit approaches.
  • Patch management-can assist businesses in identifying systems that require patching, locating the patches, and swiftly deploying them before attackers can launch a zero-day attack. This is done by establishing a formal procedure and putting automated technologies in place.
  • Incident Response Plan – having a specific plan focused on zero-day attacks can reduce confusion and increase the chances of detecting, mitigating and reducing the damage caused by zero-day attacks.


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