Common-13.4.0.tgz Vulnerability: Analysis And Fix

by Alex Johnson 50 views

This article provides an in-depth analysis of the vulnerability found in the common-13.4.0.tgz library, its potential impact, and the steps required to remediate it. This vulnerability, identified as CVE-2025-66035, has a severity score of 0.0 and affects projects using this version of the Angular common library. Understanding the details of this vulnerability is crucial for maintaining the security and integrity of your applications.

Understanding the Vulnerability: CVE-2025-66035

The core issue lies within the Angular HTTP client's XSRF (Cross-Site Request Forgery) protection mechanism. Specifically, the vulnerability, identified as CVE-2025-66035, involves a XSRF token leakage via protocol-relative URLs in Angular HTTP clients. To fully grasp the implications, let's break down the key components:

XSRF Protection in Angular

Angular's HttpClient includes a built-in mechanism to protect against XSRF attacks. This defense works by checking if a request URL starts with a protocol (http:// or https://) to determine if it is a cross-origin request. If the URL does not explicitly specify a protocol, the system may misinterpret the request's origin, leading to vulnerabilities.

The Protocol-Relative URL Problem

The vulnerability arises when a URL starts with // (a protocol-relative URL). The Angular HTTP client incorrectly treats these URLs as same-origin requests. Consequently, the XSRF token is automatically added to the X-XSRF-TOKEN header, even when it should not be. This behavior results in the unauthorized disclosure of the XSRF token to an attacker-controlled domain.

Vulnerability Details

  • Vulnerable Library: common-13.4.0.tgz
  • Vulnerability: CVE-2025-66035
  • Severity: Low (CVSS Score: 0.0)
  • Type: Credential Leak by App Logic
  • Affected Component: Angular HTTP client
  • Root Cause: Incorrect handling of protocol-relative URLs (//)
  • Impact: Unauthorized disclosure of XSRF token

This vulnerability can be exploited if an attacker can control the URL to which the Angular application sends requests. By using a protocol-relative URL, the attacker can trick the application into sending the XSRF token to their domain, potentially leading to a compromise of user sessions or sensitive data. The CVSS score of 0.0 indicates a low severity, primarily because the vulnerability requires specific conditions to be exploitable, such as the use of protocol-relative URLs, and has no impact on Confidentiality, Integrity, and Availability directly. However, the risk should not be dismissed, as an attacker can combine this with other vulnerabilities to create a more severe exploit chain.

Impact and Risk Assessment

While the Common Vulnerability Scoring System (CVSS) score for CVE-2025-66035 is 0.0, indicating a low severity, it’s essential to understand the potential implications within the context of your application. The primary risk stems from the unauthorized disclosure of the Cross-Site Request Forgery (XSRF) token. Although the impact metrics for Confidentiality, Integrity, and Availability are rated as None, the underlying issue of credential leakage can lead to further security compromises if exploited.

Potential Risks

  1. Session Hijacking: If an attacker obtains a valid XSRF token, they can potentially impersonate a user and perform actions on their behalf. This can lead to unauthorized access to user accounts and sensitive data.
  2. Data Manipulation: An attacker might use a stolen XSRF token to modify data within the application, leading to data corruption or unauthorized changes.
  3. Privilege Escalation: In certain scenarios, an attacker could use a compromised XSRF token to escalate their privileges within the application, granting them access to administrative functions or other restricted areas.
  4. Chained Exploits: The XSRF token leakage can be a stepping stone for more complex attacks. For instance, an attacker could combine this vulnerability with other weaknesses in the application to achieve a more significant impact.

Risk Mitigation

To effectively mitigate the risks associated with CVE-2025-66035, it’s important to consider the specific context of your application and how it handles URLs. Here are several factors to evaluate:

  • Usage of Protocol-Relative URLs: Assess how frequently your application uses protocol-relative URLs (i.e., URLs starting with //). If these are commonly used, the risk is higher.
  • URL Validation and Sanitization: Determine whether your application has robust mechanisms to validate and sanitize URLs. Proper input validation can prevent attackers from injecting malicious URLs.
  • Security Headers: Check if your application implements security headers such as Content Security Policy (CSP), which can help mitigate the impact of XSRF attacks.
  • Regular Security Audits: Conduct regular security audits and penetration testing to identify and address potential vulnerabilities proactively.

Recommended Actions

  • Upgrade Angular Common: The most effective way to address this vulnerability is to upgrade to a patched version of @angular/common. Versions 19.2.16, 20.3.14, and 21.0.1 and later include the fix for CVE-2025-66035.
  • Avoid Protocol-Relative URLs: As a workaround, avoid using protocol-relative URLs in HttpClient requests. Instead, use relative paths (starting with a single /) or fully qualified, trusted absolute URLs.
  • Implement Security Best Practices: Follow security best practices such as input validation, output encoding, and the principle of least privilege to minimize the attack surface.

Remediation Steps

The recommended solution is to upgrade the @angular/common library to a version that includes the fix for CVE-2025-66035. Specifically, versions 19.2.16, 20.3.14, and 21.0.1 and later versions contain the necessary patches. Here’s a step-by-step guide on how to remediate this vulnerability:

1. Check Your Current Angular Version

First, determine the version of @angular/common you are currently using. You can find this information in your project’s package.json file. Open the file and look for the @angular/common entry under the dependencies section.

{
  "dependencies": {
    "@angular/common": "13.4.0",
    ...
  }
}

In this example, the project is using version 13.4.0, which is vulnerable.

2. Update to a Patched Version

Use npm or yarn to update the @angular/common package to a patched version. The patched versions are 19.2.16, 20.3.14, and 21.0.1. Choose the version that is compatible with your project’s Angular version.

Using npm:

npm install @angular/common@latest

This command will install the latest version of @angular/common. If you need to specify a particular version, use:

npm install @angular/common@21.0.1

Using yarn:

yarn add @angular/common@latest

To install a specific version:

yarn add @angular/common@20.3.14

3. Verify the Update

After updating the package, verify that the correct version is installed. Check your package.json file again to confirm that the @angular/common version has been updated.

4. Test Your Application

It is crucial to thoroughly test your application after updating the @angular/common package. Run your test suite, perform manual testing, and ensure that all functionalities are working as expected. Pay special attention to areas of your application that use the HttpClient and handle URLs.

5. Address Protocol-Relative URLs

As a supplementary measure, review your codebase for any instances of protocol-relative URLs (//). Replace these with either relative paths (starting with /) or fully qualified, trusted absolute URLs. This practice will help prevent similar vulnerabilities in the future.

For example, instead of:

this.http.get('//api.example.com/data').subscribe(data => { ... });

Use:

this.http.get('/api/data').subscribe(data => { ... });

Or:

this.http.get('https://api.example.com/data').subscribe(data => { ... });

6. Commit and Deploy

Once you have updated the package, verified the changes, and addressed protocol-relative URLs, commit your changes and deploy the updated application to your environments.

Alternative Workarounds

If upgrading the @angular/common library is not immediately feasible, there are alternative workarounds you can implement to mitigate the vulnerability. These workarounds should be considered temporary measures until you can perform the upgrade.

1. Avoid Protocol-Relative URLs

The most straightforward workaround is to avoid using protocol-relative URLs in your Angular application. As explained earlier, these URLs are the root cause of the vulnerability. Replace any instances of protocol-relative URLs with either relative paths or fully qualified, trusted absolute URLs.

2. URL Sanitization and Validation

Implement robust URL sanitization and validation mechanisms in your application. This can help prevent attackers from injecting malicious URLs that could exploit the vulnerability. Ensure that all URLs are properly encoded and validated before being used in HttpClient requests.

3. Content Security Policy (CSP)

Configure a Content Security Policy (CSP) for your application. CSP is a security standard that helps prevent a wide range of attacks, including XSS and data injection attacks. By setting appropriate CSP directives, you can restrict the sources from which the browser is allowed to load resources, reducing the risk of an attacker exploiting the XSRF token leakage.

Here’s an example of a CSP header that you might use:

Content-Security-Policy: default-src 'self'; script-src 'self' https://trusted-scripts.example.com; style-src 'self' https://trusted-styles.example.com; img-src 'self' data:; connect-src 'self' https://api.example.com;

This CSP header sets the following directives:

  • default-src 'self': Only allow resources from the same origin by default.
  • script-src 'self' https://trusted-scripts.example.com: Allow scripts from the same origin and https://trusted-scripts.example.com.
  • style-src 'self' https://trusted-styles.example.com: Allow styles from the same origin and https://trusted-styles.example.com.
  • img-src 'self' data:: Allow images from the same origin and data URLs.
  • connect-src 'self' https://api.example.com: Allow connections to the same origin and https://api.example.com.

Adjust the CSP directives based on your application’s specific requirements.

4. Intercept and Modify HttpClient Requests

Another workaround involves intercepting HttpClient requests and modifying the URLs before they are sent. You can create an HttpInterceptor that checks for protocol-relative URLs and transforms them into fully qualified URLs. This approach adds an extra layer of defense and ensures that no protocol-relative URLs are used in your application.

Here’s an example of an HttpInterceptor that implements this workaround:

import { Injectable } from '@angular/core';
import { HttpInterceptor, HttpRequest, HttpHandler, HttpEvent } from '@angular/common/http';
import { Observable } from 'rxjs';

@Injectable()
export class ProtocolRelativeUrlInterceptor implements HttpInterceptor {
  intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    let url = req.url;
    if (url.startsWith('//')) {
      url = 'https:' + url; // Or 'http:' depending on your needs
      const modifiedReq = req.clone({ url });
      return next.handle(modifiedReq);
    }
    return next.handle(req);
  }
}

To use this interceptor, you need to provide it in your application module:

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { HttpClientModule, HTTP_INTERCEPTORS } from '@angular/common/http';
import { ProtocolRelativeUrlInterceptor } from './protocol-relative-url.interceptor';

@NgModule({
  imports: [
    BrowserModule,
    HttpClientModule
  ],
  providers: [
    {
      provide: HTTP_INTERCEPTORS,
      useClass: ProtocolRelativeUrlInterceptor,
      multi: true
    }
  ],
  bootstrap: [AppComponent]
})
export class AppModule { }

Conclusion

The vulnerability in common-13.4.0.tgz (CVE-2025-66035) highlights the importance of staying up-to-date with security patches and following secure coding practices. While the CVSS score indicates a low severity, the potential for XSRF token leakage should not be ignored. By upgrading to a patched version of @angular/common and avoiding protocol-relative URLs, you can effectively mitigate this vulnerability and enhance the security of your Angular applications.

Remember to always test your applications thoroughly after applying updates or workarounds to ensure that all functionalities are working correctly. Regular security audits and penetration testing are also crucial for identifying and addressing potential vulnerabilities proactively.

For more information on web application security and XSRF protection, visit the OWASP (Open Web Application Security Project) website.