7 Common Web-App Vulnerabilities

November 10, 2021

Web application vulnerabilities are system flaws, or weaknesses, in a web-based app. They occur primarily due to a lack of validation or sanitation of form inputs, misconfiguring web servers, app design flaws, and more. These vulnerabilities can be exploited to gain access to the app and compromise its security as well as user data. Since a web app needs to interact with multiple users across multiple networks, it is easy for hackers to find weak links and take advantage.

While there are hundreds of web app vulnerabilities, here are 7 of the most common ones:

No Multi-factor Authentication

One of the most common critical vulnerabilities and a gaping hole when it comes to security flaws is the lack of multi-factor authentication (MFA). Given that the end customer is the weakest link with their easy-to-hack passwords, and that the implications of not enforcing it are immense, there is a dire need for MFA in today’s security landscape.

Poor Management of Credentials

In order to access a web application, a user needs to input two pieces of information- their login ID and password. The application then compares this data to the information stored in the database. If they match, a user is granted access. Sometimes, databases store this information without encryption, making it easy for attackers to steal data and use them to access the app.

Improper Session Management

This ranges from not invalidating session tokens on authentication events such as logging out to attacks called “pass the cookie” wherein an attacker can steal a session cookie from another user or admin account and replace their own session token with the stolen one. For example, when a user logs out of a web app, a session token is allotted upon providing valid login credentials. This token is valid for a limited amount of time, or it will invalidate itself once the user has logged out. In many cases, a user can pass this session token upon logging out by simply hitting the ‘back’ button, thereby regaining access due to tokens not being properly disposed of. It is important to patch this vulnerability by implementing an ‘app timeout’ functionality and educating users on the importance of logging out.

Insecure Password Change Feature

Have you ever seen a web app requiring your existing password in order to allow you to change to a new password? Browser password managers make this requirement dangerous. Applications can no longer disable autocomplete to prevent password disclosure. It is possible to retrieve the password when it has been stored in the browser’s manager and use it as part of the ‘password-change’ process. Incorporating multi-factor authentication when changing a user’s password is a way to solve the problem.

Poor Password Requirements

As annoying as it may seem, requiring a certain password length or complexity is one of the best practices to adopt to prevent password leaks. Some poor password requirements include not requiring the use of a password at all, despite passwords being a part of the authentication process; and single-character passwords being permitted. Passwords with no complexity requirements (upper/lower case, numbers, special characters needed) are another example.

Improper Patch Management

Vulnerable web servers, CMS platforms, and plugin libraries are sometimes used in apps. To a hacker, these vulnerabilities offer easy sources of information about the underlying host. More severe vulnerabilities can lead to cross-site scripting, SQL injection, or command and control execution. These are often the first places an attacker will look, and the implications can be massive, depending on which feature is found to be vulnerable. Good patch management policies that require regular checks for vulnerabilities, as well as updates when needed, will help remedy this.

Encapsulation of Codes

While many vulnerabilities leverage web browser access, encapsulation focuses on the weaknesses in how the web app has been coded. Encapsulation refers to the bundling of data and actions that can be taken on that data into a single unit. On one hand, it is beneficial as it hides details about how the code works while creating a better user interface. For example, a developer can bundle access controls such as read/write permissions into an app’s ability to retrieve data. When the user requests information, the app provides only the data that they have permission to access. On the other hand, if a developer doesn’t properly draw a line between the data and the actions taken across different areas of the app, it poses an encapsulation vulnerability. Attackers can request an action that they know will result in an error message. The error message will give them information about how the application works, so they can find a workaround.

Organizations need to continuously monitor their web app’s control effectiveness. SureShield offers an outside-in view of your web app’s security posture and gives you visibility into the likelihood of a data breach. With this information, you can prioritize your strategy and gain a stronger web app security posture. Read our past blogs on how to build a vulnerability management program and the 4 stages of a critical vulnerability management program.

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