Reflected XSS vs. Stored XSS

Attribute	Reflected XSS	Stored XSS
Execution	Executed in real-time	Stored on the server and executed later
Delivery	Delivered via URL parameters or form inputs	Delivered via stored data in a database
Impact	Can affect multiple users at once	Can affect individual users or all users accessing the vulnerable page
Visibility	Visible in the URL or response content	Not visible to users, stored in the backend

Introduction

Cross-Site Scripting (XSS) is a common vulnerability found in web applications that allows attackers to inject malicious scripts into web pages viewed by other users. There are different types of XSS attacks, with Reflected XSS and Stored XSS being two of the most prevalent. While both types of attacks involve injecting malicious scripts into web pages, they differ in how the scripts are delivered and executed.

Reflected XSS

Reflected XSS, also known as Non-Persistent XSS, occurs when the malicious script is reflected off a web server and executed in the victim's browser. This type of attack typically involves sending a link containing the malicious script to the victim, who then clicks on the link. The script is then executed in the context of the victim's session, allowing the attacker to steal sensitive information or perform actions on behalf of the victim.

One common example of Reflected XSS is when an attacker crafts a malicious URL that contains a script, such as a login form that sends the victim's credentials to the attacker's server. When the victim clicks on the link and submits the form, the script is executed, and the attacker can capture the victim's login credentials.

Reflected XSS attacks are typically short-lived, as the malicious script is not stored on the server and must be delivered to the victim through a specific link or action. This makes it more difficult for attackers to carry out large-scale attacks, but it can still be effective in targeted attacks against specific individuals or organizations.

Stored XSS

Stored XSS, also known as Persistent XSS, occurs when the malicious script is stored on the server and executed every time a user accesses the vulnerable page. This type of attack is more dangerous than Reflected XSS because the script is permanently stored on the server, allowing it to be executed multiple times and potentially affecting a larger number of users.

One common example of Stored XSS is when an attacker injects a malicious script into a comment field on a website. When other users view the comment, the script is executed in their browsers, allowing the attacker to steal their session cookies or perform actions on their behalf.

Stored XSS attacks are more difficult to detect and mitigate than Reflected XSS attacks because the malicious script is stored on the server and executed automatically whenever a user accesses the vulnerable page. This makes it easier for attackers to carry out large-scale attacks and target a wider range of users.

Comparison

While both Reflected XSS and Stored XSS involve injecting malicious scripts into web pages, they differ in how the scripts are delivered and executed. Reflected XSS attacks are short-lived and require the victim to interact with a specific link or action to execute the script, while Stored XSS attacks are persistent and automatically executed every time a user accesses the vulnerable page.

• Reflected XSS attacks are typically more difficult to carry out than Stored XSS attacks because they require the attacker to trick the victim into clicking on a malicious link or performing a specific action.
• Stored XSS attacks are more dangerous than Reflected XSS attacks because the malicious script is permanently stored on the server and can affect a larger number of users over a longer period of time.
• Reflected XSS attacks are easier to detect and mitigate than Stored XSS attacks because the malicious script is not stored on the server and must be delivered to the victim through a specific link or action.
• Stored XSS attacks are more difficult to detect and mitigate than Reflected XSS attacks because the malicious script is stored on the server and executed automatically whenever a user accesses the vulnerable page.

Conclusion

In conclusion, both Reflected XSS and Stored XSS are serious security vulnerabilities that can be exploited by attackers to steal sensitive information, perform actions on behalf of users, or carry out other malicious activities. While Reflected XSS attacks are short-lived and require user interaction to execute the malicious script, Stored XSS attacks are persistent and automatically executed every time a user accesses the vulnerable page. It is important for web developers to be aware of these vulnerabilities and implement proper security measures to protect against XSS attacks.