Server-side parameter pollution
Summary: Server-side parameter pollution occurs when a website embeds user input in a server-side request to an internal API without adequate encoding, letting an attacker manipulate or inject parameters. PortSwigger describes testing this by placing URL-encoded characters like # and & into query strings, form fields, headers, and URL path parameters, and by injecting structured data such as JSON to add fields like access_level.
What's compelling: The article notes that overriding a parameter with name=administrator may enable logging in as the administrator user, and that injecting access_level into server-side JSON may give the user peter administrator access.
Read the original at PortSwigger Research ↗
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- Vulnerabilities & Patching
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