How To Scan A Web Application
For Vulnerabilities

Learn about PurpleSec’s fully managed vulnerability management services.

Author: Eryk Waligora / Last Updated: 03/24/2023

Reviewed By: Josh Allen & Jason Firch, MBA

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You can scan a web application and website in 5 steps including setting up the scanner, scanning the application for vulnerabilities, having a security analyst prioritize vulnerabilities based on business risk, delivering scan results and the assessment, and remediating and retesting vulnerabilities.

What Is A Web Application Scan?

A web application scan is an in-depth examination of a web application’s security, using automated or manual techniques to identify potential vulnerabilities, flaws, and weaknesses.

Regularly conducting these scans enables developers to address and fix the discovered issues, ultimately enhancing the application’s overall security.

The goal of the scan is to identify potential security risks that could be exploited by attackers and then prioritize the issues on a severity or risk based approach.

The scanner will search for weak passwords, outdated software versions, missing patches, misconfigured systems, and other common issues that can lead to compromise or data theft.

Learn More: Top 10 Most Exploited Security Vulnerabilities In 2022

What Does An Application Scan Look For?

Many security professionals follow the OWASP Top Ten as their guide when assessing the security posture of an application.

The scanner itself will look for common application vulnerabilities such as SQL injection attacks, cross-site scripting (XSS) attacks, insecure cookies, and session management issues.

The scanner will also check for out-of-date software versions that may contain known vulnerabilities that have yet to be patched.

How Long Does The Scan Take?

The length of time required depends on the size of the system being scanned and any additional custom scans requested by the customer.

Scans typically take several hours up to a few days, depending on the complexity of the environment being scanned.

One major reason for this is due to inputs, or attack surface, of which web applications commonly have a higher volume compared to static web pages, for instance.

An increase in inputs to scan means and increase in time.

Another significant cause for why scans can take longer is the number of false positives they can generate.

In many cases, scans could produce up to 50%, 60%, or even 70% false positives, requiring the security analyst to sift through the outputs and deliver the relevant vulnerabilities for remediation.

How Often Do I Need To Scan Applications Or Websites For Vulnerabilities?

While it’s generally recommended that organizations perform regular scans every month or so depending on their risk profile, there are several factors why a web application scan should occur frequently or independent of regular cadences.

The factors that determine how often you scan your applications include:

• Compliance standards – Regular scanning for web application vulnerabilities can help organizations comply with industry regulations and standards, such as PCI DSS, HIPAA, and GDPR.
• Practicing good cyber hygiene – Scanning more often can also help maintain good cyber hygiene and a strong security posture by identifying potential security weaknesses before they can be exploited by attackers.
• Responding to emerging threats – After discovering an emerging threat, it is important to scan web applications more regularly to identify any vulnerabilities that may have been exploited. Organizations should prioritize attending to critical software that is vulnerable to attack by deploying necessary security patches and updates as soon as possible.
• Significant infrastructural changes – After significant application infrastructural changes, it’s important to scan for web application vulnerabilities. When changes are made to an application’s infrastructure, such as adding new features or updating software components, it can inadvertently introduce new vulnerabilities.
• Keeping up with business operations – As businesses evolve and grow, they introduce new web applications, features, and functionalities to support their operations. It’s important to scan regularly for web application vulnerabilities to keep up with the fast pace of business and ensure that these new additions do not introduce security weaknesses or vulnerabilities.

Why Scanning Application And Websites For Vulnerabilities Is Important

Regularly scanning applications and websites for vulnerabilities is a crucial aspect of maintaining a secure online presence, as it helps organizations defend against potential cyber-attacks and protect sensitive data.

Learn More: 9 Data Security Strategies You Need To Implement In 2023

This essential practice not only aids in identifying and addressing vulnerabilities but also enables organizations to stay current with evolving threats and security innovations.

By adopting a proactive approach, businesses can minimize downtime and financial loss while improving their overall security posture.

Some key reasons why scanning applications and websites is important include:

• Facilitating secure development and validating application updates.
• Monitoring third-party components and ensuring proper access control.
• Supporting risk management and optimizing remediation efforts.
• Assessing legacy systems and benchmarking security performance.
• Safeguarding brand reputation and enhancing user experience.

By incorporating these strategies, organizations demonstrate their commitment to cybersecurity, fostering trust with customers and partners.

This dedication not only helps maintain compliance but also contributes to an organization’s success and reputation in today’s increasingly digital world.

Steps To Scan A Website & Applications For Vulnerabilities

In this section, you’ll learn the step-by-step process of setting up a web application scanner and navigating through the entire vulnerability management lifecycle, empowering you to effectively detect and address potential security risks and maintain a secure environment.

• Set Up The Scanner
• Scan The Application For Vulnerabilities
• Security Analyst Prioritizes Vulnerabilities
• Scan Results & Assessment Is Delivered
• Remediation & Rescanning

1. Set Up The Scanner

To set up the scanner, you need to download software that is compatible with your operating system.

After downloading, configure the settings based on your specific needs, including the IP address ranges to be targeted during scanning intervals, potentially across multiple networks.

Authentication credentials are also required to access certain services, if necessary.

Once the settings have been configured, the scanner can be set to run scheduled scanning intervals automatically each month at predetermined times.

This can be manually triggered through command line tools provided by third-party vendors upon request, although most organizations prefer to have scheduled automatic intervals configured ahead of time to reduce the overhead associated with manual triggering each month.

This saves valuable time and allows team members responsible for managing vulnerability scanning operations to focus their energy elsewhere throughout the organization, helping everyone better utilize available resources while simultaneously ensuring that all critical hosts remain safe.

2. Scan The Application For Vulnerabilities

After completing the initial setup procedures, the next step is to actually run the scanning interval using the predefined configurations established earlier.

This involves setting parameters for the specific target environment being scanned, taking into consideration the IP address ranges assigned to the particular segment target network(s) being scanned, along with any authentication credentials required to access certain services.

Once these parameters are established, the type(s) of results desired must be specified, such as whether text-based output is preferable or if HTML format is preferred.

Once all parameters are finalized, simply press “Go”, “Start”, or whatever command there may be to initiate the scanning process for automated vulnerability management.

3. Security Analyst Prioritizes Vulnerabilities

After the results are generated via the automated scanning interval, the final step is to review the results themselves and determine whether the findings are legitimate or false positives requiring further investigation.

The security analyst is responsible for managing the overall lifecycle security operations processes, assigning severity and risk-based levels to individual findings, and giving the highest priority to those deemed most dangerous and potentially leading to a compromise of the entire infrastructure.

Quickly responding with remediation efforts can significantly reduce risk exposure.

By doing so, the security analyst can focus their efforts on the most impactful issues first, allowing for a more efficient and effective use of resources.

Learn More: How To Conduct A Vulnerability Assessment

4.  Scan Results & Assessment Is Delivered

After completing the review and vulnerability assessment of individual findings, the security analyst is responsible for delivering the final report.

This report summarizes the findings, prioritizing the levels of importance and offering recommendations for addressing the issues and eliminating threats altogether.

Once the report is delivered, it serves as the basis for a rough timeline outlining the remediation efforts needed to completely resolve the issues.

This helps ensure that everyone involved understands the seriousness of the matter and can correctly estimate the amount of resources required to complete the task successfully.

By providing a clear and concise report, the security analyst can help guide the organization’s efforts towards improving the security posture of their web applications.

5. Remediation & Rescanning

After the initial remediation efforts are complete, the final step is to rerun the exact same scanning interval to verify that the issue is indeed resolved.

This helps ensure that no further effort is required to complete the job properly and provides peace of mind knowing that all identified issues have been addressed correctly.

Once the remediation efforts have been verified, confirming that everything is fixed, and rescanning helps provide further reassurance that everything has been done correctly according to plan.

The best part is that rescanning involves rerunning the same exact set of commands, which saves a lot of time and avoids unnecessary repetition of tasks that have already been performed previously.

This approach makes life easier and simplifies the entire process from start to finish.

It also provides tangible proof that the job has been done correctly, resulting in fewer stress headaches, fewer sleepless nights, and happier IT professionals.

By working smarter instead of harder and maximizing available resources, the organization can achieve a full return on investment every single time.

Popular Web Vulnerability Scanners

There are many different types of web vulnerability scanners available today but some of the most popular scanner options include:

• Acunetix
• Burp Suite Pro
• Netsparker
• OWASP ZAP
• AppSpider

Each scanner offers different features and benefits, so be sure to research them thoroughly before making a decision on which one best suits your specific needs and budget.

For example, Acunetix, Burp Suite Pro & Netsparker all focus primarily on automated scanning while OWASP ZAP & AppSpider offer both automated & manual testing capabilities.

Common Pitfalls To Overcome When Scanning Web Applications

One of the biggest challenges when it comes to scanning web applications for vulnerabilities is that many organizations don’t understand the scope of what they’re trying to protect.

It’s easy to overlook some areas in your application, such as user input fields or third-party libraries that may contain security flaws.

However, one of the major reasons for missed scope is the lack of insight and awareness into the web application’s complete attack surface.

In addition, manually testing each component is expensive and can be tedious and time-consuming.

Automating vulnerability scans can help alleviate this issue, but there is still a component that requires significant resources and expertise.

Another challenge is keeping up with changes in technology and security best practices.

For example, new versions of software may contain patches or updates that address known vulnerabilities in previous versions.

If you don’t keep your system up-to-date, you are at greater risk of attack from hackers who are actively exploiting known security flaws.

Finally, failing to plan for potential issues or risks will result in a reactive posture, forcing security teams to become overburdened and overwhelmed just trying to respond to an incident or catch up to a backlog, leading to serious consequences.

Before starting a vulnerability scan, you should create a plan that outlines what you want to accomplish and addresses any potential issues or risks upfront.

This will help ensure that your scan goes smoothly and that potential problems are addressed before they arise.

How Much Does A Web Vulnerability Scan Cost?

The cost of performing a web vulnerability scan depends on several factors, including how complex the application is and whether you choose to perform the scan internally or hire an outside service provider or contractor.

One of the important factors in estimating cost is determined by fully qualified domain names (FQDN).

FQDNs are complete domain names that identify a specific web address on the internet, including the top-level domain and all subdomains, separated by periods. For example, “www.example.com“.

Let’s break down some of these factors in cost in more detail:

1. Number of FQDNs: The more FQDNs that need to be scanned, the more time and resources the vendor will need to allocate to the project. This may result in a higher cost for the customer.
2. The complexity of FQDNs: Some FQDNs may be more complex to scan than others, particularly if they involve multiple subdomains or have unique configurations. The vendor may need to spend more time configuring the scanning tools to properly scan these FQDNs, which could result in a higher cost.
3. Type of scan: Different types of scans may be required for different FQDNs. For example, a basic vulnerability scan may be sufficient for a simple website, while a more advanced scan that includes penetration testing may be needed for a more complex web application. The cost of the scan will depend on the type of scan required.
4. Frequency of scans: Depending on the customer’s needs, vulnerability scans may need to be conducted on a regular basis (e.g., weekly or monthly) or more ad hoc following certain incidents. The vendor may offer different pricing tiers based on the frequency of scans required.

Performing Scans In House

Conducting web application security scans internally demands a considerable amount of technical proficiency and access to sophisticated tools and resources, which can be costly for organizations lacking an established cybersecurity team.

A security analyst who conducts the actual scan and analyzes the outputs can cost up to $80,000 or more alone. In addition to the human factor, the scanner itself is likely to run $3,000-$5,000.

Furthermore, managing and overseeing the entire process, from start to finish, can be time-consuming, especially if multiple applications are being scanned concurrently or if the scope of work is too extensive for one individual to manage independently.

Costs can certainly run up quickly!

Hire A Security Contractor

Hiring a security contractor can provide additional support during peak workloads or when specialized skills are required beyond what your team has available internally—but it typically comes at a premium price tag due to their experience and expertise in specific areas.

This expertise can cost anywhere between $2,500-$4,000 for a single web application vulnerability scan, which is a significant investment for many organizations.

However, this cost can be justified by the quality of the work performed and the assurance that vulnerabilities have been properly identified and addressed.

Hire A Vulnerability Scanning Service Provider

There are also many companies out there offering comprehensive (and often affordable) vulnerability scanning services, which can save both time and money compared with hiring internal staff or contractors per project basis.

Although, they may not offer the same level of customization that individual contractors do, depending on their specific offerings/services provided and pricing structure.

For instance, pricing for a single scan can be around $2,500, while quarterly scans can range from $8,000-$10,000 depending on the provider and the scope of the work required.

Wrapping Up

Scanning web applications and websites for vulnerabilities is a critical component of an organization’s cyber security strategy.

By following a structured process, such as setting up the scanner, scanning for vulnerabilities, prioritizing risks, assessing results, and performing remediation and rescanning, businesses can effectively safeguard their digital assets and maintain a secure online environment.

Regular vulnerability scanning not only enables organizations to comply with industry regulations but also helps to build trust with clients and partners.

By staying informed on the latest security challenges and employing the best practices outlined in this article, organizations can ensure that they are adequately protected against cyber threats and are well-equipped to maintain a strong security posture.