Gowthamaraj Rajendran (@fuffsec)FollowSystem Weakness--ListenShareCross-Site Scripting (XSS) is one of the most prevalent, obstinate, and dangerous vulnerabilities in web applications. It allows attackers to inject malicious scripts into web pages viewed by other users, leading to a range of potential attacks such as stealing user sessions, defacing websites, or redirecting the user to malicious sites. In this blog post, we will delve into the details of XSS vulnerabilities, how to identify them during a Secure Code Review, and what measures can be taken to prevent them.Cross-Site Scripting (XSS) attacks occur when an application includes untrusted data in a new web page without proper validation or escaping, or updates an existing web page with user-supplied data using a browser API that can create HTML or JavaScript. XSS vulnerabilities enable attackers to inject malicious scripts into web pages viewed by other users.XSS attacks can be classified into three types:During a secure code review, the primary goal is to identify places in the code where the application includes untrusted data in a web page. Here are some things to look for:Here is a checklist to follow when performing a secure code review to identify XSS vulnerabilities:Preventing XSS vulnerabilities involves proper design and coding practices. Here are some measures that can be taken:In conclusion, XSS is a serious threat to application security, but it can be effectively mitigated with proper coding and design practices. A thorough secure code review is a crucial step in identifying and fixing these vulnerabilities before the application goes into production.References:----System WeaknessSecurity Researcher | DevSecOps | Red Teamer | Malware Analyst | Bug Bounty Hunter | Software developer (OSCP, CRTP, eWPTX, SSCP)Gowthamaraj Rajendran (@fuffsec)inSystem Weakness--Mr JokarinSystem Weakness--2Yashwant Singh 🐧inSystem Weakness--5Gowthamaraj Rajendran (@fuffsec)inSystem Weakness--1Viral Vaghela--Kira--1vvek--Prathamesh Ghumade--Abinjohn--1Rajkaran--HelpStatusWritersBlogCareersPrivacyTermsAboutText to speechTeams