Would you please consider the following?
1) Include a HSTS header
Strict-Transport-Security: max-age=15768000
(6 months, or some other reasonable value)
2) Redirect
http://manager.linode.com to
https://manager.linode.com
I don't think this has security benefits beyond cosmetics, but it seems like the right thing to do anyway.
3) Set X-Frame-Options: SAMEORIGIN
4) Create a Content-Security-Policy header
https://dvcs.w3.org/hg/content-security ... n.dev.html
5) Check that recent nginx memory disclosure vuln doesn't apply to your web app, or has been patched. (The manger.l.c server reports itself as 0.7.x)
http://cve.mitre.org/cgi-bin/cvename.cg ... -2012-1180