CVE-2024-1968 in scrapy
Summary
by MITRE • 05/20/2024
In scrapy/scrapy, an issue was identified where the Authorization header is not removed during redirects that only change the scheme (e.g., HTTPS to HTTP) but remain within the same domain. This behavior contravenes the Fetch standard, which mandates the removal of Authorization headers in cross-origin requests when the scheme, host, or port changes. Consequently, when a redirect downgrades from HTTPS to HTTP, the Authorization header may be inadvertently exposed in plaintext, leading to potential sensitive information disclosure to unauthorized actors. The flaw is located in the _build_redirect_request function of the redirect middleware.
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Analysis
by VulDB Data Team • 07/15/2025
The vulnerability identified in CVE-2024-1968 affects the scrapy web scraping framework and represents a critical security flaw in how HTTP redirects are handled during the request lifecycle. This issue specifically manifests when a web application performs redirects that change the scheme from HTTPS to HTTP while maintaining the same domain, creating a scenario where sensitive authentication credentials could be inadvertently exposed. The problem stems from the framework's failure to properly implement the HTTP specification requirements for Authorization header handling during cross-origin redirects, which directly violates established web security standards and protocols.
The technical implementation flaw resides within the _build_redirect_request function of scrapy's redirect middleware component, where the authorization header is not properly stripped when processing redirects that alter the scheme but preserve the host. This function fails to conduct the necessary validation checks required by the Fetch standard specification, which explicitly states that Authorization headers must be removed when redirects involve changes to scheme, host, or port parameters. The vulnerability creates a scenario where legitimate security controls are bypassed, as the framework does not perform the required cross-origin boundary checks that would normally prevent credential leakage between secure and insecure communication channels.
The operational impact of this vulnerability extends beyond simple credential exposure, as it creates potential attack vectors for man-in-the-middle adversaries who can intercept and exploit the plaintext transmission of authentication tokens. When a user agent follows a redirect from HTTPS to HTTP, the Authorization header containing sensitive information such as bearer tokens, API keys, or session credentials becomes visible in the HTTP request, making it susceptible to network-level interception and unauthorized access. This flaw particularly affects applications that rely on scrapy for automated data collection and web scraping operations, where the framework may be processing sensitive authentication flows that could be exploited by malicious actors.
Security professionals should consider this vulnerability in the context of CWE-352, which addresses Cross-Site Request Forgery, and ATT&CK technique T1566, related to Phishing, as the exposure of authorization headers creates opportunities for credential harvesting attacks. The flaw also aligns with CWE-200, which deals with Exposure of Sensitive Information, and represents a failure in proper security boundary enforcement. Organizations utilizing scrapy for web scraping activities should immediately implement mitigations including updating to patched versions of the framework, implementing additional middleware validation, and conducting security reviews of existing scraping operations that may be vulnerable to this scheme-downgrade attack vector.
The remediation approach should focus on ensuring that scrapy's redirect middleware properly implements the Fetch standard requirements for cross-origin redirect handling, specifically requiring the removal of Authorization headers when scheme changes occur during redirects. Security teams should also consider implementing monitoring for unauthorized scheme changes in their scraping infrastructure and establish proper security controls around credential handling in automated web access scenarios. This vulnerability highlights the importance of maintaining strict adherence to web security standards and the critical need for proper HTTP protocol implementation in security-sensitive applications.