Access restriction bypass via origin spoof
Medium Web Application Scanning Plugin ID 98096
SynopsisAccess restriction bypass via origin spoof
DescriptionOrigin headers are utilised by proxies and/or load balancers to track the
originating IP address of the client.
As the request progresses through a proxy, the origin header is added to the
existing headers, and the value of the client's IP is then set within this header.
Occasionally, poorly implemented access restrictions are based off of the
originating IP address alone.
For example, any public IP address may be forced to authenticate, while an
internal IP address may not.
Because this header can also be set by the client, it allows cyber-criminals to
spoof their IP address and potentially gain access to restricted pages.
Scanner discovered a resource that it did not have permission to access, but been
granted access after spoofing the address of localhost (127.0.0.1), thus bypassing
any requirement to authenticate.
SolutionRemediation actions may be vastly different depending on the framework being used, and how the application has been coded. However, the origin header should never be used to validate a client's access as it is trivial to change.