The remote host is missing an update to iceweasel announced via advisory DSA 1649-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%201649-1

Several remote vulnerabilities have been discovered in the Iceweasel web browser, an unbranded version of the Firefox browser. For details, please visit the referenced security advisories. For the stable distribution (etch), these problems have been fixed in version 2.0.0.17-0etch1. Packages for hppa will be provided later. For the unstable distribution (sid), these problems have been fixed in version 3.0.3 of iceweasel and 1.9.0.3-1 of xulrunner. We recommend that you upgrade your iceweasel package.