PlugSecex adds sensible HTTP headers to secure the web applications written in Elixir.

Example

pipeline :browser do
  plug PlugSecex
end

You can also specify to override or disable particular set of headers.

pipeline :browser do
  plug PlugSecex,
    overrides: [
      "x-dns-prefetch-control": "on",
      "x-frame-options": "DENY",
      "custom-header": "value"
    ],
    except: [
      "x-powered-by"
    ]
end

If you need to determine one of these at run time - for instance, in order to use a content security policy that allows resources from a location configured in environment variables - you can pass a "module, function, arguments" tuple; calling that function with those arguments must return a list as shown in the previous example.

pipeline :browser do
  plug PlugSecex,
    overrides: {MyModule, :overrides, [arg1, arg2]},
    except: {MyModule, :exceptions, [arg3]}
end

The supported headers and their values by default are:

"x-content-type-options": "nosniff",
"x-dns-prefetch-control": "off",
"strict-transport-security": "max-age=31536000",
"x-xss-protection": "1; mode=block",
"x-frame-options": "SAMEORIGIN",
"content-security-policy": "default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-inline' 'unsafe-eval'"

The headers that are removed by default are:

"x-powered-by",
"server"