|
COMMAND Apache cross site scripting via SSI error page SYSTEMS AFFECTED Apache 2.0 prior to 2.0.43 PROBLEM Matt Murphy [mattmurphy@kc.rr.com] found : A vulnerability exists in the SSI error pages of Apache 2.0 that involves incorrect filtering of server signature data. The vulnerability could enable an attacker to hijack web sessions, allowing a range of potential compromises on the targeted host. This particular attack involves a lack of filtering on HTTP/1.1 "Host" headers, sent by most recent browsers. The vulnerability occurs because Apache doesn't filter maliciously malformed headers containing HTML markup before passing them onto the browser as entity data. The following URL will demonstrate the attack: http://%3CIMG%20SRC%3D%22%22%20ONERROR%3D%22alert%28document%2Ecookie%29%22%3E.apachesite.org/raise_404 Some browsers submit the malicious host header when parsing this request: Host: <img src="" onerror="alert(document.cookie)"> Apache returns this malicious host in the form of a server signature: <ADDRESS>Apache/2.0.39 Server at <IMG SRC="" ONERROR="alert(document.cookie)">.apachesite.org</ADDRESS> ... SOLUTION The Apache Software Foundation has released Apache 2.0.43 to eliminate this vulnerability. It is available from http://www.apache.org/dist/httpd/