The remote host is missing an update to iceweasel announced via advisory DSA 2200-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%202200-1

This update for Iceweasel, a web browser based on Firefox, updates the certificate blacklist for several fraudulent HTTPS certificates. More details can be found in a blog posting by Jacob Appelbaum of the Tor project: https://blog.torproject.org/category/tags/ssl-tls-ca-tor-certificates-torbrowser For the oldstable distribution (lenny), this problem has been fixed in version 1.9.0.19-9 of the xulrunner source package. For the stable distribution (squeeze), this problem has been fixed in version 3.5.16-6. For the unstable distribution (sid), this problem has been fixed in version 3.5.18-1. For the experimental distribution, this problem has been fixed in version 4.0~rc2-1. We recommend that you upgrade your iceweasel packages.