Web security

Web security is also known as “Cybersecurity”. It basically means protecting a website or web application by detecting, preventing and responding to cyber threats. Websites and web applications are just as prone to security breaches as physical homes, stores, and government locations.

An effective approach to web security threats must, by definition, be proactive and defensive.


Difference between Authentication and Authorization

When speaking with other programmers and IT professionals, I often encounter confusion regarding the distinction between authorization and authentication. And of course, the fact the abbreviation auth is often used for both helps aggravate this common confusion. This confusion is so common that maybe this issue should be included in this post as “Common Web Vulnerability Zero”

Let’s clarify the distinction between these two terms:

  • Authentication: Verifying that a person is (or at least appears to be) a specific user, since he/she has correctly provided their security credentials (password, answers to security questions, fingerprint scan, etc.).
  • Authorization: Confirming that a particular user has access to a specific resource or is granted permission to perform a particular action.


What are common web app security vulnerabilities?

Attacks against web apps range from targeted database manipulation to large-scale network disruption. Let’s explore some of the common methods of attack or “vectors” commonly exploited.

Cross site scripting (XSS) – XSS is a vulnerability that allows an attacker to inject client-side scripts into a webpage in order to access important information directly, impersonate the user, or trick the user into revealing important information.

SQL injection (SQi) – SQi is a method by which an attacker exploits vulnerabilities in the way a database executes search queries. Attackers use SQi to gain access to unauthorized information, modify or create new user permissions, or otherwise manipulate or destroy sensitive data.The problem here is that the attacker can inject commands to these entities, resulting in loss of data and hijacking clients’ browsers.

Anything that your application receives from untrusted sources must be filtered, preferably according to a whitelist. You should almost never use a blacklist, as getting that right is very hard and usually easy to bypass. Antivirus software products typically provide stellar examples of failing blacklists. Pattern matching does not work.

Denial-of-service (DoS) and distributed denial-of-service (DDoS) attacks – Through a variety of vectors, attackers are able to overload a targeted server or its surrounding infrastructure with different types of attack traffic. When a server is no longer able to effectively process incoming requests, it begins to behave sluggishly and eventually deny service to incoming requests from legitimate users.

Memory corruption – Memory corruption occurs when a location in memory is unintentionally modified, resulting in the potential for unexpected behavior in the software. Bad actors will attempt to sniff out and exploit memory corruption through exploits such as code injections or buffer overflow attacks.

Buffer overflow – Buffer overflow is an anomaly that occurs when software writing data to a defined space in memory known as a buffer. Overflowing the buffer’s capacity results in adjacent memory locations being overwritten with data. This behavior can be exploited to inject malicious code into memory, potentially creating a vulnerability in the targeted machine.

Cross-site request forgery (CSRF) – Cross site request forgery involves tricking a victim into making a request that utilizes their authentication or authorization. By leveraging the account privileges of a user, an attacker is able to send a request masquerading as the user. Once a user’s account has been compromised, the attacker can exfiltrate, destroy or modify important information. Highly privileged accounts such as administrators or executives are commonly targeted.

Data breach – Different than specific attack vectors, a data breach is a general term referring to the release of sensitive or confidential information, and can occur through malicious actions or by mistake. The scope of what is considered a data breach is fairly wide, and may consist of a few highly valuable records all the way up to millions of exposed user accounts.


Few common mistake of web Developer

  1. The URL might contain the session id and leak it in the referer header to someone else.
  2. The passwords might not be encrypted either in storage or transit.
  3. The session ids might be predictable, thus gaining access is trivial.
  4. Session fixation might be possible.
  5. Session hijacking might be possible, timeouts not implemented right or using HTTP (no SSL security), etc…
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