HTTP_PROXY Environment Variable Vulnerability in PHP by The PHP Group

CVE-2016-5385

Summary

The vulnerability arises from PHP versions up to 7.0.8 failing to handle namespace conflicts as specified in RFC 3875. This oversight allows attackers to exploit the HTTP_PROXY environment variable, potentially routing an application's outbound HTTP requests to arbitrary proxy servers by manipulating the Proxy header in an HTTP request. Applications utilizing getenv('HTTP_PROXY') or those configured via CGI can be particularly vulnerable, which creates opportunities for data exfiltration or other malicious activities.

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