Main Vulnerabilities in Web Applications

Understanding web application vulnerabilities is crucial for safeguarding sensitive data, maintaining user trust, and ensuring operational continuity. Being aware of these vulnerabilities allows developers and businesses to preemptively address potential security threats, which can prevent financial losses, reputational damage, and legal issues. Additionally, this knowledge is vital for complying with security regulations and standards, making it an essential aspect of responsible web application development and maintenance.

Here is a list of key vulnerabilities we’ve successfully resolved over time, based on experience.

1. Cross-Site Request Forgery (CSRF): Cross-Site Request Forgery (CSRF) is a type of security vulnerability in web applications. It allows an attacker to induce users to perform actions that they do not intend to do on a web application where they are authenticated. For example, if a user is logged into their bank’s website, an attacker could trick them into executing unwanted actions, like transferring money, by clicking a malicious link or visiting a compromised webpage. CSRF exploits the trust that a site has in the user’s browser, and it typically involves forged HTTP requests like GET or POST to perform actions without the user’s consent.
2. Local File Disclosure: This vulnerability allows an attacker to read files from the server that hosts the web application. This might include system files, application source code, or sensitive configuration files, depending on the permissions set on the server. LFD can be exploited through insecure file handling practices within the application, such as when user input is improperly sanitized and used to construct file paths that the server then accesses.
3. Full Path Disclosure (FPD): This vulnerability occurs when error messages from a web server include the absolute paths to files that are involved in the error. An attacker can use this information to gain a deeper understanding of the server’s directory structure and possibly other sensitive information that can be used to craft further attacks. FPD is often a result of poor error handling and can be mitigated by configuring the server to handle errors more securely without disclosing detailed internal information.
4. Rate Limiting Mechanisms:
   Rate limiting mechanisms are tools used to control the frequency of user actions to prevent abuse and ensure system stability. They are commonly used in contexts like API access, web traffic management, and securing login attempts to prevent overload and enhance security.
5. Stored Cross-Site Scripting (XSS): a web security vulnerability where an attacker injects malicious scripts into content that is saved (stored) on a web server. This content is then served as part of web pages to other users. Unlike reflected XSS, which involves scripts being immediately echoed by server-side scripts into the user’s browser, stored XSS is more insidious as the malicious content persists on the server and affects all users who access the infected content
6. Reflected Cross-site Scripting (XSS): occurs when a web application sends back user-input data as part of a webpage without properly sanitizing it first. This unsanitized input can include malicious scripts that execute in a user’s browser, potentially leading to unauthorized access to sensitive data. Preventing Reflected XSS involves thoroughly validating and encoding user inputs to ensure they are treated safely as data rather than executable code.
7. SQL Injection: a security vulnerability that occurs when an attacker manipulates a SQL query by injecting malicious SQL code through user input areas of an application, such as form fields or URL parameters. This allows the attacker to execute arbitrary SQL commands on the database, which can lead to unauthorized access, data theft, data manipulation, or even destruction of the database.
8. Insecure Direct Object References (IDOR): occur when an application provides direct access to objects based on user-supplied input. This vulnerability allows attackers to bypass authorization and access resources directly by modifying the value of a parameter used to directly point to an object, such as a file, database record, or key. For example, if a URL or request parameter allows direct access to specific user accounts by changing a number (e.g., user_id=123), an attacker could change user_id to a different number to access someone else’s account information without proper authorization.
9. Session Expiration: this is a security measure in web applications that ends a user session after a set period of inactivity or a fixed time. It helps prevent unauthorized access by automatically logging users out, reducing the risk of security breaches if a user forgets to log out or their session is hijacked. Effective session management includes implementing timeouts and absolute expirations to ensure sessions do not remain open indefinitely.
10. Application Security Headers: these are HTTP response headers that, when set by web applications, can help enhance the security of an application by instructing browsers on how to behave when handling the site’s content. These headers protect against a variety of attacks such as cross-site scripting (XSS), clickjacking, and other code injection attacks.
11. Information Exposure through HTTP response headers: occurs when a web server inadvertently reveals sensitive information within its HTTP headers. This information can include details about the server’s software, configuration, or other data that should not be publicly accessible. Attackers can use this information to tailor attacks, exploiting specific vulnerabilities known to be associated with the disclosed versions or configurations.
12. Unneeded/deprecated cipher Block Chaining ciphers: Tthe CBC mode but are considered obsolete or less secure due to various vulnerabilities. Cipher Block Chaining is a method of encrypting plaintext where each block of plaintext is XORed (exclusive or operation) with the previous ciphertext block before being encrypted. While this method provides certain security benefits, it is susceptible to certain types of attacks such as padding oracle attacks.
13. SSL 64-bit Block Size Cipher Suites Supported (SWEET32): this vulnerability affects cipher suites using 64-bit block ciphers like 3DES and Blowfish in TLS. Due to their small block size, these ciphers are susceptible to a birthday attack when large amounts of data are encrypted with the same key. Over time, an attacker can gather enough data to discover patterns and decrypt sensitive information, despite the encryption. This vulnerability highlights the need to move away from older 64-bit block ciphers to more secure alternatives.
14. BEAST (Browser Exploit Against SSL/TLS): This vulnerability targets a flaw in the implementation of the Cipher Block Chaining (CBC) mode in SSL 3.0 and TLS 1.0. The BEAST attack allows an attacker to decrypt data exchanged between the client and the server by exploiting predictable initialization vectors (IV) used in these older protocols. To mitigate this, newer versions of TLS (1.1 and higher) implement more secure measures for IVs and encryption protocols.
15. TLS 1.0 and TLS 1.1 (Deprecated versions): older versions of the Transport Layer Security (TLS) protocol, deprecated due to significant security vulnerabilities. TLS 1.0, introduced in 1999, is susceptible to attacks like BEAST, which exploits weaknesses in its CBC mode cipher suites. Both versions lack support for modern cryptographic standards, leading to their official deprecation in 2020 to encourage the adoption of more secure versions, such as TLS 1.2 and TLS 1.3.

Learn how we solved XSS (Cross site scripting) on our latest blog post.