OAuth Flow Manipulation

OAuth Flow Manipulation occurs when attackers exploit weaknesses in OAuth authentication implementations to gain unauthorized access to systems. During the Gain Access phase, attackers target vulnerabilities in OAuth flows by intercepting authorization codes, manipulating redirect URIs, performing token substitution, or exploiting improper state parameter validation. By interfering with the OAuth handshake between the client application, authorization server, and resource server, attackers can bypass authentication controls, obtain valid access tokens, and ultimately assume legitimate user identities. Common attack vectors include open redirectors, insufficient client verification, token leakage through referrer headers, and cross-site request forgery attacks against authorization endpoints. This sub-technique is particularly dangerous as it exploits trusted authentication frameworks while potentially leaving minimal evidence of compromise in security logs.