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10 Web Application
Security Threats and How
to Mitigate Them


StackHawk|March 1, 2023

Delve into 10 common web application security threats, their consequences, how web apps are vulnerable to them, and how to mitigate them.

Web application security is crucial to ensuring the safety and security of online systems and their users. As more and more daily activities and transactions move online, the importance of securing web applications becomes increasingly clear. Daily reports of breaches and always-changing security threats mean that security is a top priority for every organization.

In this article, we'll explore ten common web application security threats, the consequences of these threats, how web applications are vulnerable to them, and how to mitigate them.

10 Web Application Security Threats

Here are the ten common web application security threats we will cover in this article:

  1. SQL injection

  2. Cross-site scripting (XSS)

  3. Cross-site request forgery (CSRF)

  4. Insecure direct object references

  5. Remote code execution

  6. Insufficient logging and monitoring

  7. Insecure cryptographic storage

  8. Failure to restrict URL access

  9. Cross-origin resource sharing (CORS) misconfiguration

  10. Using components with known vulnerabilities

1. SQL Injection

A SQL injection attack is executed when an attacker injects malicious code into an application's database through user input fields. These types of attacks can accomplish many different things. Two of the most common outcomes include allowing the attacker to gain unauthorized access to sensitive data stored in the database. Depending on what data the database is storing, the attack could get access to passwords, financial information, and personal data. The second outcome could be the manipulation or deletion of data. For instance, a user may be able to execute a DROP TABLE or DROP DATABASE command.

You can mitigate this with the following steps:

  • Validate user input.

  • Use output encoding, which involves converting special characters such as < and > into their HTML entity equivalents, to prevent them from being interpreted as HTML code.

  • Use prepared statements, parameterized queries, or stored procedures instead of dynamic SQL whenever possible.

Most languages and frameworks have recommended ways of handling form input. By combing frontend and backend standards to prevent SQL injection from happening, your application can increase its security against this type of threat.

2. Cross-Site Scripting (XSS)

Cross-site scripting (XSS) attacks involve injecting malicious code or a malicious script into a website. The website then executes the script, allowing the attacker to steal sensitive user data, like session tokens and cookies, or perform other actions.

There are two main types of XSS attacks: reflective and stored. Reflective XSS attacks involve injecting malicious code into a website that is immediately executed. Stored XSS attacks involve injecting malicious code into a website that is stored and executed at a later time.

If successful, a cross-site scripting attack can result in the theft of user session IDs, website defacement, and redirection to malicious sites, thereby enabling phishing attacks.

You can mitigate this with the following steps:

  • Validate user input.

  • Use output encoding techniques.

  • Use auto-sanitization libraries such as OWASP AntiSamy.

  • Implement a content security policy.

Similar to the recommendation for SQL injection, using modern web frameworks generally tends to steer developers towards secure coding practices to avoid XSS and similar attacks.

3. Cross-Site Request Forgery (CSRF)

Cross-site request forgery (CSRF) is a type of attack that involves tricking a victim into performing an action on a website without their knowledge. This can be done by injecting a malicious link or form into a website that the victim is already authenticated on.

When the victim clicks the link or submits the form, the action is performed on their behalf, potentially leading to data loss or unauthorized access.

You can mitigate this with the following steps:

  • Leverage CSRF protections already built into the framework you are using, if applicable.

  • Use CSRF tokens. These are unique, randomized values associated with a user's session and are included in forms and links to verify the authenticity of the request.

  • Use SameSite cookies. These are a type of cookie that is only sent with requests to the same origin as the cookie's creation. This can help prevent attackers from being able to send requests on behalf of a victim, as they would not have access to the victim's SameSite cookies.

4. Insecure Direct Object References (IDOR)

Insecure Direct Object References, or IDOR, occur when an application exposes direct object references, such as URLs or database keys, that allow attackers to access restricted data by manipulating these references.

For example, an application may allow users to access their account information by entering their account number in a URL, such as "". An attacker could potentially access other users' account information by changing the account number in the URL.

You can mitigate this with the following steps:

  • Implement proper access controls and session management. This involves setting up mechanisms to ensure that only authorized users have access to certain resources or data. The OWASP cheat sheets on authorization and authentication can be helpful resources for reviewing best practices in these areas.

  • Validate user input. To help prevent attackers from manipulating direct object references to access-restricted data, ensure that user input is the correct type, length, and format.

  • Avoid using predictable references. Instead, consider using globally unique identifiers (GUIDs) to prevent attackers from guessing the direct object references they need to access restricted data.

As noted in the mitigation steps above, IDOR-based vulnerabilities don’t occur on their own. These vulnerabilities must be coupled with other vulnerabilities to become an effective attack vector.

5. Remote Code Execution (RCE)

Remote Code Execution (RCE) attacks allow attackers to execute arbitrary code on a server, potentially leading to full system compromise and unauthorized access to sensitive data.

RCE attacks can occur through a variety of means, such as exploiting vulnerabilities in code libraries or injecting malicious code through user input fields.

A successful RCE attack can have several consequences. These include Denial of Service (DoS) attacks, exposure of sensitive data, illicit cryptocurrency mining, and execution of malware. In some cases, a successful RCE attack can even give full control over the compromised machine to the attacker.

You can mitigate this with the following steps:

  • Sanitize user input.

  • Implement secure memory management. RCE attackers can potentially take advantage of memory management flaws such as buffer overflows. Conducting regular security vulnerability scans on your applications can help you identify buffer overflow and memory-related vulnerabilities that an attacker could exploit.

  • Always keep your operating system and your third-party software up to date to ensure that you have the latest security patches.

  • Limit the attacker's ability to move through a network y implementing network segmentation, access management, and a zero-trust security strategy.

RCE attacks have been a major source of breaches in the last few years, many leading to worldwide security emergencies. One that many people will remember is the Log4j fiasco discovered in 2021 where multiple RCE vulnerabilities were discovered in Log4j. These RCE vulnerabilities allowed attackers to exploit vulnerable applications to execute Cryptojacking attacks and other malware on compromised servers.

6. Insufficient Logging and Monitoring

Insufficient logging and monitoring refer to a lack of proper logging and monitoring processes in place to detect and respond to security threats. This can allow attackers to go unnoticed and continue to compromise the system, potentially leading to data loss and financial loss.

It’s also important to be aware of what is being logged. If secure information, such as credit card numbers or passwords, are being written to logs, attackers who gain access to the logs could use this information maliciously. Fraudulent credit card charges or unauthorized access to a system could be easily executed.

You can mitigate this with the following steps:

  • Enable logging for key events and actions in your application and monitor logs regularly.

  • Use log analysis tools. These can help automate the process of reviewing logs and identify potential security issues or anomalies more quickly and efficiently.

  • Set up alerting systems to notify administrators of any potential security issues in real time, allowing them to respond more quickly to potential threats.

  • Ensure that sensitive information is either not included in logs or is properly masked.

7. Insecure Cryptographic Storage

Insecure cryptographic storage refers to the improper handling of cryptographic keys, such as storing them in plain text or using weak keys. This can allow attackers to gain access to sensitive data through compromised cryptographic keys.

You can mitigate this with the following steps:

  • Use strong cryptographic algorithms, such as AES or RSA, to secure stored data.

  • Implement key management best practices, such as regularly rotating keys and securely storing them, to help prevent unauthorized access to encrypted data.

  • Use secure storage solutions, such as hardware security modules or encrypted storage devices, to help further protect encrypted data.

One suggestion is also to audit the data that you need to store in an encrypted state. The best way to protect data is to simply not store it at all. If sensitive data is being stored without need, it may be best to forego the storage of this data to lessen the data that potential attackers have access to.

8. Failure to Restrict URL Access / Broken Access Control

Failure to restrict URL access refers to a lack of proper access controls that allow unauthorized users to access restricted pages and resources. This can allow attackers to access sensitive data and potentially compromise the system.

This security threat is mostly similar and related to the IDOR vulnerabilities we discussed earlier. The core differentiating factor between the two is that IDOR tends to give the attacker access to information in the database, while failure to restrict URL access allows the attacker access to special functions and features that should not be available to any typical user.

You can mitigate this with the following steps:

  • Implement proper access controls by setting up authentication and authorization processes to ensure that only authorized users have access to certain resources or functions.

  • Use role-based authorization. The enforcement mechanism should deny all access by default, requiring explicit grants to specific users and roles for access to every page.

  • Implement adequate authorization measures at relevant stages of user web app use.

Many routing libraries and routing mechanisms built into modern web frameworks tend to protect against this by default. By making sure that the application routing is set up correctly, these types of vulnerabilities can be completely avoided.

9. Cross-Origin Resource Sharing (CORS) Misconfiguration

Cross-Origin Resource Sharing (CORS) is a security feature that allows a web server to specify which domains are allowed to access its resources. However, if CORS is misconfigured, it can allow attackers to access restricted resources from a different origin. This could potentially expose data through services that can be used without authorization.

You can mitigate this with the following steps:

  • Properly configure CORS headers.

  • Use CORS libraries that provide an easy-to-use interface for configuring CORS headers to help you configure CORS properly.

Many server-side frameworks and platforms can aid developers in properly configuring CORS for their services. Developers should be aware of how CORS can be configured in the framework of their choosing. One common reason for CORS security misconfiguration is that when developers are creating applications locally they will set an entirely open CORS policy for easier development. Ensuring that these policies do not get checked into production code is crucial.

10. Using Components with Known Vulnerabilities

Using components with known vulnerabilities refers to the use of outdated code libraries, frameworks, or other components with known vulnerabilities.

Many websites today are built using complex components, which can make it difficult for development teams to understand their internal workings. This can create potential vulnerabilities if a component contains known security issues that are not properly addressed.

You can mitigate this with the following steps:

  • Keep track of component versions. You can address any vulnerabilities by regularly checking for updates and staying up to date with the latest versions of components.

  • Use security scanners to help you identify known vulnerabilities in components and alert developers to potential issues.

Using tools like Dependabot can help keep your dependencies up to date automatically. By using scanning tools and automation, keeping dependencies secure and up-to-date is easy to do as part of the development process.

What Is the Biggest Security Threat to a Web Application?

It's difficult to determine the single biggest threat to a web application. This is because it depends on the specific web application and its unique vulnerabilities.

However, the most common application security threats according to the OWASP Top 10 are broken access control, cryptographic failures, and injection (including SQL injection and cross-site scripting). By using the latest tools for security scanning and monitoring, as well as the latest secure coding practices, developers and their organizations can limit their exposure. 


Web applications are an integral part of modern life, and as such, they're a common target for attackers. By understanding common security threats and implementing proper mitigation techniques, web application developers and administrators can help protect their systems and users. To assist with this process, consider using a security platform like StackHawk to automate and improve your application security testing.

With StackHawk, developers can add Dynamic Application Security Testing directly into their CI/CD pipelines. StackHawk scans the running application for vulnerabilities that are outlined in the OWASP Top 10 and more. Developers are then able to view reports for each test that is executed, uncover vulnerabilities, and be guided on fixes. The best part: all of this can happen before the application hits production. To see the benefits of StackHawk for yourself, sign up today for a free trial.

Learn more

  • Read on to see how StackHawk’s CSO, Scott Gerlach talks about “Shift Left” being more than just a buzzword here

  • Check out why Omdia’s On the Radar report highlights StackHawk as an “interesting alternative to most other DAST tools” here.

  • Getting started with StackHawk? Check out Advice and Answers from the amazing StackHawk team here

StackHawk  |  March 1, 2023

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