Red Hat Software Collections for Red Hat Enterprise Linux 6 and 7
This issue applies when you're using CGI with PHP, Python or Go. Nginx does not support CGI in its default configuration, however many users apply a solution such as simplecgi or fcgiwrap to provide this functionality via the inbuilt FastCGI support.
If your CGI script opens a HTTP connection to another service any outgoing requests generated in turn from the attackers original request can be redirected to an attacker controlled proxy.
To prevent this issue in Nginx configuration, add the following line to your fastcgi configuration (normally in
fastcgi_param HTTP_PROXY "";
See NGinx - Fast CGI Module for more information on the
fastcgi_param configuration directive.
See HTTPoxy - CGI "HTTP_PROXY" variable name clash for more information.
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