CVE-2022-31033 is a vulnerability identified in the sparklemotion Mechanize library, a tool widely used for automating web interactions such as handling cookies, following redirects, submitting forms, and navigating links programmatically. The vulnerability exists in versions prior to 2.8.5 of Mechanize, where the Authorization HTTP header is improperly leaked after a redirect to a different port on the same site. Specifically, when a web request is redirected to a different port on the same domain, Mechanize continues to send the Authorization header, which may contain sensitive credentials such as bearer tokens, API keys, or basic authentication credentials, to the redirected endpoint. This behavior violates the principle of least privilege and can expose sensitive authentication information to unauthorized actors who control or monitor the redirected port. Since the Authorization header is intended to be scoped to a specific endpoint or service, leaking it to other ports increases the attack surface and risk of credential compromise. There are no known workarounds for this issue other than upgrading to Mechanize version 2.8.5 or later, where the behavior has been corrected to prevent the header from being sent on redirects to different ports. No exploits in the wild have been reported as of the publication date, but the vulnerability represents a clear risk in automated web clients that rely on Mechanize for authentication and session management. The vulnerability is classified under CWE-200, indicating exposure of sensitive information to unauthorized actors. The issue was publicly disclosed in June 2022 and has been enriched by CISA, highlighting its relevance to cybersecurity stakeholders.

For European organizations, this vulnerability poses a risk primarily to applications and automation scripts that use the Mechanize library for web interactions involving authentication. If an attacker can control or monitor the redirected port, they may capture sensitive Authorization headers, leading to credential theft and unauthorized access to protected resources. This could result in data breaches, unauthorized transactions, or lateral movement within networks. Sectors with high reliance on automated web clients, such as financial services, e-commerce, and government digital services, may be particularly impacted. The exposure of credentials could facilitate further attacks, including privilege escalation and data exfiltration. Although no active exploitation has been reported, the vulnerability's presence in automation tools used in development and testing environments could lead to inadvertent leaks of sensitive tokens or keys, increasing the risk of compromise. Given the widespread use of Mechanize in open-source projects and internal tools, the scope of affected systems could be significant, especially in organizations that have not updated dependencies regularly. The impact on confidentiality is high due to potential credential exposure, while integrity and availability impacts depend on subsequent misuse of stolen credentials. The vulnerability does not require user interaction but does require the use of vulnerable Mechanize versions in automated workflows.

The primary and only effective mitigation is to upgrade all instances of the Mechanize library to version 2.8.5 or later, where the issue has been fixed. Organizations should perform an inventory of software projects and automation scripts that use Mechanize and update dependencies accordingly. Additionally, developers should audit redirect handling logic in their applications to ensure that sensitive headers like Authorization are not sent to unintended endpoints, especially when redirects involve different ports. Implementing strict network segmentation and monitoring for unusual traffic to non-standard ports can help detect potential exploitation attempts. Where possible, use short-lived tokens or ephemeral credentials in Authorization headers to limit the impact of any leakage. Employing application-layer logging and alerting on unexpected Authorization header transmissions can provide early warning. Finally, organizations should integrate dependency scanning tools into their CI/CD pipelines to detect and remediate vulnerable library versions proactively.