According to Zone-H, 13 Nasa web sites were hacked and defaced. The hacker provided a link to a video where US soldiers cheer after they kill an Iraqi. The message "The war in iraq, kill is a play!" was placed by the link.
Nasa's main site ( http://www.nasa.gov
) was not defaced and it is online. It appears they took the defaced web sites offline. The Apache 1.3.27 Web server with PHP ran the sites that were hit. One deface: http://www.zone-h.org/
"We can suppose that the server was remotely compromised using a vulnerability in a PHP script, then the defacer probably gained root privileges using the local root exploit for the Linux kernel 2.4.22..published by iSEC Security Research last week." Source