XSS vs. CSRF

Cross-Site Scripting (XSS) and Cross-Site Request Forgery (CSRF) attacks may operate quietly, but their impact is anything but subtle. If your web applications aren’t secure, these attacks can compromise user sessions, leak sensitive data, and escalate into large-scale breaches. And no industry is beyond their reach. 

Earlier in 2024, Ticketmaster's breach exposed sensitive data on 560 million customers. The stolen data included names, emails, addresses, phone numbers, ticket sales, and order details, and was put on sale for $500,000.

Vulnerabilities such as XSS and CSRF can significantly harm your organization and undermine user trust. To combat this, DevSecOps teams must understand these threats and prioritize security from the beginning of the development process. 



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What is XSS (Cross-Site Scripting)?

Cross-site scripting (XSS) is a vulnerability that lets attackers inject malicious scripts into web pages, which then execute in users’ browsers. By embedding JavaScript or HTML into trusted pages, attackers can steal session cookies, hijack login credentials, or access sensitive data without direct user interaction. Since these scripts run under the site’s trusted domain, they bypass typical security controls.

XSS attacks come in three primary forms:

•  Stored XSS occurs when an attacker embeds malicious scripts into a target website’s database, delivered to users when they access specific pages. 
• Reflected XSS works by embedding the script in a URL or a form submission. The script is then “reflected” back to the user as part of the webpage content. 
• DOM-based XSS is more complex. It manipulates the document object model (DOM) structure, causing the client-side code to execute the attack payload directly in the browser.



A recent example from October 2024 involved hackers exploiting an XSS vulnerability in Roundcube Webmail, targeting government agencies in CIS countries. Attackers embedded malicious scripts into emails that triggered upon opening, allowing unauthorized access to sensitive data within the victims’ accounts.



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The Consequences of XSS Attacks and Why Prevention Matters

At their core, XSS attacks exploit trust, tricking users into thinking they’re interacting with legitimate content when, in reality, malicious scripts are being executed in their browsers. These scripts can hijack user sessions, allowing attackers to impersonate users, swipe sensitive data, or even escalate privileges within an application. For example, privilege escalation flaws like Dirty Cow have been linked to unauthorized access affecting millions of devices worldwide. 

In high-stakes apps like banking or healthcare, one XSS vulnerability can lead to severe breaches, exposing users and organizations to substantial financial and regulatory fallout. The risk of leaving XSS vulnerabilities unpatched is well-documented, with studies consistently ranking XSS among the most pervasive threats to web applications. 

For example, XSS vulnerabilities constitute up to 18% of all bug bounties on platforms like HackerOne. Unpatched XSS flaws allow repeated exploitation, eroding user trust and exposing applications to multiple attack cycles.

What is CSRF (Cross-Site Request Forgery)?

CSRF manipulates the trust a web application places in an authenticated user’s session, tricking the server into executing unauthorized actions on behalf of the user. Because the site trusts the user’s session, it processes the request without any additional checks, letting the attacker perform actions as if they were the user – often without the user even realizing it.

There are two main types of CSRF attacks:

1. Traditional CSRF targets a user’s session by embedding malicious forms or scripts on an external site. When the user unknowingly triggers these requests, the attacker can manipulate the user's account, causing unintended actions like transferring funds, abusing subscriptions, or changing account settings.
2. Login CSRF is more focused on session manipulation. It tricks users into logging into an attacker-controlled account. Once logged in, the attacker can monitor the user’s activities or access sensitive information under the false session.



For example, in 2022, TeamCity’s OAuth integration had a vulnerability that allowed attackers to inject arbitrary query parameters, bypassing the intended GitHub validation steps. The victim’s  TeamCity account was then linked to an attacker-controlled GitHub account, effectively hijacking the session. 

CSRF Attacks: The Risks and Importance of Prevention

Applications assume that authenticated requests are safe once a user is logged in. By piggybacking on this trust, attackers can send malicious requests that appear to come from the user’s session, leading to actions like account changes, unauthorized transfers, or sensitive data exposure. 

In enterprise environments, CSRF vulnerabilities can compromise access control by allowing attackers to issue high-privilege requests, potentially disrupting system operations or exposing internal data.

CSRF prevention is critical for preserving the integrity of high-stakes user actions and minimizing business impact, particularly in applications managing financial data, personal information, or elevated permissions.



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Key Differences Between XSS and CSRF

XSS and CSRF attacks work on two very different trust assumptions within web applications. XSS injects malicious scripts into trusted web pages. It relies on users assuming the site is safe and trusting the content they see on the page. In contrast, CSRF takes advantage of the server’s trust in the authenticated user, tricking the server into accepting unauthorized requests as legitimate.

Here's how they compare in a few other areas:

• User Interaction: XSS typically needs user engagement, like clicking a link, to execute in the browser. CSRF requires that only the user be logged in.
• Session Requirement: CSRF relies on the user being authenticated and using session cookies to issue requests. XSS can operate with or without a session, although an active session increases its reach.
• Scope of Actions: XSS gives attackers direct control over the browser environment, allowing them to alter content, lift cookies, or access local storage – essentially anything on the page. CSRF is more limited, only executing actions that the authenticated user is allowed to perform.
• Attack Initiation: Attackers embed XSS  in the site and usually inject it through input fields or manipulated URLs. CSRF comes from an external source, such as a crafted link or form on another site.
• Risks: XSS poses a high risk of data theft and session hijacking in web applications, including those built with frameworks like Angular, single-page applications (SPAs), and dynamic platforms. CSRF’s primary risks lie in unauthorized actions, such as transferring funds or altering user settings.



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Preventing XSS and CSRF in Modern DevOps Pipelines

In the fast-moving DevOps pipeline, constant code changes can create prime opportunities for XSS and CSRF vulnerabilities if you don’t embed security at every stage. Such vulnerabilities often slip through in code due to assumptions about input safety and trust in authenticated sessions. 

Focus on input sanitization and encoding to effectively prevent XSS and CSRF. It’s not just about filtering user input but encoding it specifically for where it’s displayed, whether in HTML, JavaScript, or URLs. Frameworks like Django and Rails help handle this, but it’s wise to ensure you encode for each unique context to avoid edge cases that generic sanitization might miss.

Content Security Policies (CSPs) add another layer by tightly controlling where scripts, styles, and other resources are loaded. Set CSP headers to limit script sources to a trusted domain and turn off inline scripts by default. Specific CSP directives, like script-src and object-src, can go a long way in locking down your resources.



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For CSRF protection, embed unique CSRF tokens tied to user sessions on any form or state-changing request. When combined with SameSite cookie attributes set to Strict or Lax, you’ll block cross-site requests that might otherwise exploit session cookies.

Automating security checks is a great way to verify that other best practices remain intact as code changes and new deployments roll out. Jit’s AppSec Platform integrates tools like Semgrep and OSV-Scanner directly into your CI/CD pipeline, so you can catch issues as your application evolves. Semgrep scans for vulnerable patterns tied to XSS and CSRF – such as unsanitized fields or absent CSRF tokens – with every code push. 

Dependencies also handle user input or session management, so it’s vital not to overlook them. OSV-Scanner checks these libraries for known vulnerabilities, helping catch issues that might otherwise let XSS or CSRF exploits sneak into production.

Build Resilience Against XSS and CSRF with Jit

Regarding XSS and CSRF, the risks are anything but hypothetical – they’re entry points for real threats that can turn minor oversights into massive breaches. For DevSecOps teams, embedding strong security early is a safeguard against these attacks' very real financial and operational impact.

Jit helps teams tackle this by integrating tools like Semgrep and OSV-Scanner directly into CI/CD workflows, turning each code push into an opportunity to catch and mitigate risks tied to XSS and CSRF. With intelligent prioritization, Jit can help your team zero in on what matters, making security feel manageable even in fast-paced development environments.

Ready to secure your pipeline? Visit Jit.io to learn more.