2024 CWE Top 25 Most Dangerous Software Weaknesses: Cross-Site Request Forgery (CSRF) CWE-352

2024 CWE Top 25 Most Dangerous Software Weaknesses: Cross-Site Request Forgery (CSRF) CWE-352

Cross-Site Request Forgery (CSRF), identified as CWE-352 in the 2024 CWE Top 25 Most Dangerous Software Weaknesses, remains a pervasive threat in the software development and cybersecurity landscape. This post dives deep into the technical, architectural, and business implications of CSRF, offering actionable insights for software architects and penetration testers.

Understanding Cross-Site Request Forgery (CSRF)

CSRF is a security vulnerability that tricks a victim into performing unintended actions on a web application where they are authenticated. By exploiting the trust that a website places in the user’s browser, attackers can force users to execute actions without their consent or knowledge.

How CSRF Works

1. Victim Authentication: The victim logs into a web application, establishing an authenticated session.
2. Malicious Request Injection: The attacker sends the victim a link, embeds a form, or uses an image tag in a malicious website to trick the victim into performing an action on the legitimate application.
3. Execution of Unauthorised Actions: The server processes the request as though it originated from the authenticated user, as it relies on browser-supplied credentials like cookies.

Impact of CSRF on Businesses

For C-Suite executives, CSRF attacks translate into real-world consequences:

• Financial Loss: Fraudulent transactions and data manipulation can lead to monetary losses.
• Reputation Damage: Breaches erode customer trust, causing long-term brand harm.
• Regulatory Penalties: Non-compliance with data protection regulations such as GDPR or CCPA due to CSRF-induced breaches can incur hefty fines.
• Operational Disruption: Exploited systems require remediation efforts, diverting resources and disrupting business operations.

CSRF in the 2024 CWE Top 25

The inclusion of CSRF in the 2024 CWE Top 25 underscores its relevance. Despite advancements in web security frameworks, the proliferation of vulnerable web applications makes CSRF an ongoing concern. Its placement is a call to action for software architects and penetration testers to prioritise robust security measures.

Anatomy of a CSRF Attack

A Practical Example

Consider an online banking application. A malicious actor crafts a script that instructs the bank to transfer funds to their account. The victim, authenticated to the bank’s website, inadvertently clicks a malicious link while browsing the internet. The bank processes the transfer request, believing it to originate from the user.

Types of CSRF Attacks

1. Stored CSRF: Malicious payloads are stored on the server and executed when users access affected resources.
2. Reflected CSRF: Malicious inputs are embedded into URLs, tricking users into clicking and triggering the payload.
3. DOM-Based CSRF: Manipulates the Document Object Model (DOM) to execute unauthorised requests.

Mitigating CSRF: Best Practices for Software Architects

1. Implement Anti-CSRF Tokens
   • Use synchroniser tokens to validate each request.
   • Tokens should be unique per session and difficult to predict.
2. Leverage Secure HTTP Headers
   • Use the SameSite attribute for cookies to restrict cross-origin requests.
   • Apply Content-Security-Policy (CSP) headers to reduce the attack surface.
3. Adopt Multi-Factor Authentication (MFA)
   • MFA adds an additional layer of verification, making it harder for attackers to exploit compromised sessions.
4. Validate Input Sources
   • Reject requests originating from unauthorised sources.
   • Use referer and origin headers for validation.

Penetration Testing for CSRF Vulnerabilities

Penetration testers play a pivotal role in identifying and mitigating CSRF risks. Here’s how:

1. Simulating Attack Scenarios
   • Use tools like Burp Suite and OWASP ZAP to craft malicious requests.
   • Test token validity and predictability.
2. Assessing Secure Headers
   • Ensure the SameSite attribute is set to Strict or Lax.
   • Check for proper implementation of CSP.
3. Validating Business Logic
   • Test workflows for unauthorised modifications.
   • Focus on critical actions like fund transfers, password resets, and data deletion.

Tools for CSRF Testing

• Burp Suite Pro: Allows custom CSRF attack creation.
• OWASP ZAP: An open-source tool for identifying CSRF vulnerabilities.
• Postman: Useful for crafting and sending HTTP requests.

Emerging Trends and Future Outlook

As web technologies evolve, so do the techniques for exploiting CSRF vulnerabilities. The following trends are reshaping the threat landscape:

1. Increased Use of Single-Page Applications (SPAs)
   • SPAs rely on client-side logic, which can introduce new CSRF risks if APIs are not secured properly.
2. Serverless Architectures
   • Serverless functions must validate input rigorously, as they can be entry points for CSRF attacks.
3. Integration with IoT
   • IoT devices often interact with web applications, expanding the attack surface for CSRF exploitation.

Case Study: The Real-World Cost of CSRF

A global e-commerce platform suffered a CSRF attack that allowed unauthorised users to change account passwords. The breach resulted in:

• Compromised User Accounts: Over 500,000 accounts were affected.
• Regulatory Action: The company faced a £2 million GDPR fine.
• Reputational Fallout: Customer confidence plummeted, impacting sales.

Lessons Learned:

• Anti-CSRF tokens must be mandatory for sensitive operations.
• Secure headers and regular penetration testing are non-negotiable.

Real-World Cyber Incidents Involving CWE-352 (CSRF)

Cross-Site Request Forgery (CSRF), identified as CWE-352, has been the root cause of several high-profile security incidents over the years. Below are notable real-world cases where CSRF attacks caused significant damage, demonstrating the critical importance of addressing this vulnerability.

1. Gmail CSRF Attack (2008)

Overview

In 2008, researchers discovered a CSRF vulnerability in Gmail that allowed attackers to add email forwarding rules to user accounts. This could redirect all incoming emails to an attacker-controlled address without the victim’s knowledge.

Impact

• Privacy Violation: Sensitive personal and business emails were exposed.
• Widespread Exploitation: Attackers used this vulnerability to target corporate accounts and intercept confidential communications.
• Public Backlash: Google faced scrutiny over its lack of proactive security measures.

Takeaways

• Implementation of Anti-CSRF Tokens: Google strengthened its defences by implementing synchroniser tokens.
• Increased Awareness: The incident raised awareness of CSRF risks among web developers and security professionals.

2. MySpace Samy Worm (2005)

Overview

Although primarily a Cross-Site Scripting (XSS) attack, the Samy Worm leveraged CSRF to propagate. Once a user visited an infected MySpace profile, the worm executed malicious code to send friend requests and post messages, spreading itself to other profiles.

Impact

• Exponential Growth: Over one million profiles were infected within 24 hours.
• Reputational Damage: MySpace’s reputation as a secure platform was severely tarnished.
• Monetary Loss: Remediation efforts and system outages cost the platform millions.

Takeaways

• Combination of XSS and CSRF: The incident highlighted how attackers often chain vulnerabilities for maximum impact.
• Need for Secure Defaults: Platforms must ensure secure implementation of authentication and input validation mechanisms.

3. ING Bank CSRF Exploit (2007)

Overview

A CSRF vulnerability in ING Bank’s online banking platform allowed attackers to initiate unauthorised fund transfers. Victims were tricked into visiting malicious websites that executed fraudulent requests on their behalf.

Impact

• Financial Loss: Customers reported unauthorised transactions from their accounts.
• Legal Action: ING faced lawsuits from affected users.
• Erosion of Trust: The incident dented customer confidence in online banking.

Takeaways

• Use of Origin and Referer Headers: Banks now validate these headers to ensure requests originate from legitimate sources.
• Security Education: Financial institutions began educating users about phishing and malicious links.

4. Facebook CSRF Vulnerability (2013)

Overview

Researchers found a CSRF vulnerability in Facebook that allowed attackers to send friend requests or ‘Like’ pages on behalf of victims. Attackers embedded malicious links in third-party websites to exploit the flaw.

Impact

• Misrepresentation: Victims’ profiles were used to promote spam pages and unauthorised content.
• Platform Integrity: The exploit undermined Facebook’s reputation for maintaining user security.

Takeaways

• Anti-CSRF Measures: Facebook introduced comprehensive CSRF protection, including token-based validation.
• Improved Bug Bounty Programmes: The platform expanded its bug bounty programme to encourage researchers to report vulnerabilities responsibly.

5. GitLab CSRF Exploit (2020)

Overview

In 2020, GitLab patched a CSRF vulnerability that allowed attackers to alter user account settings and disable two-factor authentication (2FA). Exploiting this flaw, attackers could compromise accounts and escalate privileges.

Impact

• Security Breach: Developers faced risks of unauthorised repository access.
• Potential Code Leaks: Sensitive source code and intellectual property were at risk.
• Reputational Damage: GitLab had to reassure its users by rolling out immediate security updates.

Takeaways

• Enforcing Multi-Factor Authentication (MFA): GitLab mandated 2FA for enhanced account security.
• Timely Patch Management: Organisations should respond swiftly to vulnerability disclosures.

6. WordPress CSRF Plugin Vulnerabilities

Overview

WordPress plugins have frequently been targeted for CSRF exploits. In one notable case, a plugin for managing administrative functionality failed to implement CSRF tokens, allowing attackers to create new administrator accounts or change settings.

Impact

• Mass Compromise: Hundreds of websites were compromised, leading to data theft and defacement.
• SEO Poisoning: Attackers injected malicious content to manipulate search engine rankings.

Takeaways

• Rigorous Plugin Review: Developers must adhere to strict security standards for plugins.
• User Responsibility: Site administrators should keep plugins up-to-date and avoid using unverified plugins.

7. Tesla CSRF Vulnerability (2020)

Overview

In 2020, researchers discovered a CSRF vulnerability in Tesla’s vehicle management platform. Exploiting the flaw, attackers could unlock doors, honk horns, or even control charging features.

Impact

• Safety Concerns: The vulnerability exposed critical vehicle operations to unauthorised control.
• Reputational Risks: Tesla’s image as a secure, high-tech brand was questioned.

Takeaways

• Securing APIs: Tesla reinforced API endpoints with CSRF tokens and user input validation.
• IoT Implications: The incident highlighted the importance of securing IoT systems against CSRF.

These real-world incidents underscore the severe consequences of CSRF vulnerabilities. Whether it is financial losses, reputational damage, or operational disruptions, the cost of neglecting CSRF defences is too high. Software architects and penetration testers must collaborate to ensure robust protection, leveraging anti-CSRF tokens, secure headers, and proactive testing.

By learning from these examples and adopting best practices, organisations can safeguard their systems, mitigate risks, and protect their users from the evolving threat landscape.

Penetration Testing Cross-Site Request Forgery (CSRF)

Penetration testing for Cross-Site Request Forgery (CSRF) involves simulating real-world attack scenarios to identify and mitigate vulnerabilities in web applications. As CSRF attacks exploit the trust a server places in a user’s browser, the role of penetration testers is to expose weaknesses in the validation of user requests and ensure robust security measures are in place.

Why Penetration Testing for CSRF Is Critical

1. Proactive Risk Mitigation: Identifying vulnerabilities before attackers exploit them prevents potential data breaches and financial losses.
2. Compliance Requirements: Many standards like PCI DSS, GDPR, and HIPAA mandate regular penetration testing.
3. Reputation Management: Ensuring robust defences helps maintain user trust and organisational reputation.

Stages of Penetration Testing for CSRF

1. Information Gathering

• Understand the Application: Identify workflows, critical features, and user roles.
• Review Authentication Mechanisms: Check if the application uses session cookies, tokens, or headers for authentication.
• Analyse HTTP Requests: Capture and review requests using tools like Burp Suite or OWASP ZAP to identify potential CSRF targets.

2. Identifying Potential CSRF Vulnerabilities

• Critical Functions: Focus on functions that have significant consequences, such as:
  • Financial transactions
  • Password changes
  • Administrative actions
• Input Validation: Test whether the application validates user inputs against an anti-CSRF token or referer headers.
• Session Management: Check if cookies are marked with the HttpOnly and Secure attributes and if they utilise the SameSite directive.

3. Crafting Malicious Requests

• Create a Test Scenario: Use an intercepted legitimate request and manipulate it for unauthorised purposes.
• Inject CSRF Payloads: Construct payloads in forms, links, or images that mimic genuine requests.
• Simulate Attacker Actions: Host the malicious payload on a different domain or send it via phishing emails.

Example CSRF Payload

<form action=”<https://example.com/transfer>” method=”POST”>

  <input type=”hidden” name=”amount” value=”1000″>

  <input type=”hidden” name=”to_account” value=”attacker_account”>

  <input type=”submit”>

</form>

By embedding this form into a malicious webpage, testers can simulate an attacker tricking a user into submitting the form while logged into the target application.

4. Testing CSRF Defences

• Token Validation:
  • Ensure the application uses unique, unpredictable anti-CSRF tokens.
  • Test whether the application accepts requests without tokens or with tampered tokens.
• Referer and Origin Header Validation:
  • Check if the server validates the referer or origin headers to confirm legitimate requests.
• Session Validation:
  • Verify that sessions are invalidated after logout to prevent token reuse.

5. Reporting Findings

• Document Vulnerabilities: Clearly outline each vulnerability, affected functionality, and potential impact.
• Provide Recommendations:
  • Implement anti-CSRF tokens.
  • Use SameSite attributes for cookies.
  • Validate referer and origin headers.

Tools for CSRF Penetration Testing

1. Burp Suite Pro
   • Automate the detection of CSRF vulnerabilities.
   • Use the CSRF PoC generator to create exploit payloads.
2. OWASP ZAP
   • Identify missing anti-CSRF tokens and insecure configurations.
   • Leverage its HUD mode for real-time testing.
3. Postman
   • Craft and send HTTP requests to test CSRF defences.
   • Use it to simulate unauthorised actions manually.
4. CSRF PoC Generator
   • Automates the creation of proof-of-concept exploits to demonstrate vulnerabilities.

Common CSRF Mitigation Challenges

1. Token Mismanagement: Incorrect implementation of anti-CSRF tokens, such as reusing tokens across sessions.
2. Third-Party Integrations: Applications relying on third-party APIs may not validate requests properly.
3. Inadequate Header Validation: Failure to enforce referer or origin header checks leaves applications vulnerable.

Best Practices for Penetration Testers

1. Focus on High-Impact Areas: Test functions that can cause significant damage, such as administrative actions and financial transactions.
2. Simulate Real-World Scenarios: Recreate attack vectors used by cybercriminals, such as phishing or malicious advertising.
3. Collaborate with Development Teams: Work with architects to integrate security controls during the development phase.
4. Retest After Fixes: Ensure identified vulnerabilities are patched and retested to confirm effectiveness.

Penetration testing for CSRF is essential to safeguard web applications from unauthorised actions and data breaches. By understanding application workflows, simulating real-world attacks, and testing defences comprehensively, penetration testers can help organisations fortify their security posture.

For software architects, collaboration with penetration testers ensures the seamless integration of CSRF protection measures into application development. By addressing CSRF risks proactively, businesses can prevent costly incidents, achieve regulatory compliance, and maintain user trust.

Cross-Site Request Forgery (CSRF) has consistently featured in critical vulnerability lists like the SANS Top 25 Most Dangerous Software Errors and the OWASP Top 10 because it poses a significant risk to web application security. Here’s why CSRF is deemed so critical:

Why CSRF Is in the SANS Top 25

The SANS Top 25 identifies the most dangerous software errors that developers should address to reduce the likelihood of exploitation. CSRF is included due to the following reasons:

1. Prevalence in Applications

• Widespread Vulnerability: CSRF vulnerabilities are common across web applications that rely on session-based authentication but lack adequate request validation mechanisms.
• Underestimated Risk: Many developers fail to consider CSRF a priority because it exploits the user’s trust, not the server’s.

2. Business and Operational Impact

• Financial Loss: CSRF attacks often result in unauthorised transactions, fund transfers, or account modifications.
• Regulatory Non-Compliance: CSRF can lead to breaches of sensitive data, exposing businesses to penalties under GDPR, CCPA, or other regulations.

3. Technical Simplicity and Effectiveness

• Low Barrier to Entry for Attackers: Exploiting CSRF requires minimal technical skill, often relying on a crafted link, form, or image tag.
• High Potential for Damage: Attackers can leverage CSRF to exploit critical functions such as password changes or financial transactions.

4. Difficulty in Detection

• CSRF attacks are difficult to detect because they exploit legitimate session cookies, making malicious requests indistinguishable from legitimate ones.

Why CSRF Is in the OWASP Top 10

The OWASP Top 10 highlights the most critical web application security risks based on exploitability, detectability, and impact. CSRF has featured prominently because:

1. Direct Link to Application Security Risks

• Impact on Critical Operations: OWASP prioritises vulnerabilities that can affect sensitive operations, and CSRF attacks often target high-value actions like fund transfers or data modification.
• Chain Exploits: CSRF can be combined with other vulnerabilities, such as Cross-Site Scripting (XSS), to maximise the impact.

2. Exploitability

• Minimal User Interaction Required: Attackers only need to trick a victim into clicking a link or loading a malicious webpage.
• Unauthenticated Attacks on Authenticated Sessions: CSRF takes advantage of authenticated sessions, making it highly exploitable in real-world scenarios.

3. Emphasis on Inadequate Security Controls

• Many web applications do not implement anti-CSRF tokens, fail to validate the Origin or Referer headers, or use insecure cookie settings, all of which are highlighted in OWASP’s guidelines.

4. Alignment with Secure Development Practices

• OWASP emphasises security by design, and CSRF exemplifies the risks of ignoring secure development principles like input validation and tokenisation.

5. Relevance Across Industries

• CSRF affects web applications across all sectors—banking, e-commerce, healthcare, and government—making it a universal concern for security practitioners.

Commonality Between SANS and OWASP Criteria

Both the SANS Top 25 and the OWASP Top 10 evaluate vulnerabilities based on the following shared factors:

1. Prevalence: CSRF is widely observed across web applications due to poor security controls.
2. Ease of Exploitation: The simplicity of executing CSRF attacks makes it a preferred method for attackers.
3. Impact: CSRF attacks often result in financial losses, reputational damage, or regulatory breaches.
4. Preventability: Despite being well-documented, CSRF vulnerabilities persist because developers often overlook basic security measures.

CSRF’s Place in Today’s Threat Landscape

Inclusion in the SANS Top 25 and OWASP Top 10 serves as a wake-up call to organisations and developers. CSRF’s consistent presence in these lists underlines the importance of adopting preventive measures such as:

• Implementing anti-CSRF tokens.
• Validating the Referer and Origin headers.
• Using secure cookie attributes (HttpOnly, Secure, SameSite).

By addressing CSRF as a priority, organisations can mitigate one of the most deceptively simple yet impactful threats to web application security.

Final Thoughts

Cross-Site Request Forgery (CWE-352) remains a significant software weakness that demands proactive mitigation strategies. For software architects, embedding security into the development lifecycle is imperative. For penetration testers, continuous evaluation of applications against CSRF risks ensures a robust defence.

Investing in preventative measures and fostering a security-first culture can safeguard organisations from the devastating effects of CSRF. By addressing this challenge head-on, businesses can protect their assets, maintain customer trust, and achieve compliance in an increasingly interconnected world.