A weakness and some vulnerabilities have been reported in AWStats, which can be exploited by malicious people to disclose system information and conduct cross-site scripting and spoofing attacks.

1) Some input isn't properly sanitised before being returned to the user. This can be exploited to execute arbitrary HTML and script code in a user's browser session in context of an affected site.

Examples:
http://[host]/awstats.pl?config=[code]
http://[host]/awstats.pl?refererpagesfilter=[code]&refererpagesfilterex=&output=refererpages&config=[config]&year=2006&month=all
http://[host]/awstats.pl?refererpagesfilter=&refererpagesfilterex=[code]&output=refererpages&config=[config]&year=2006&month=all
http://[host]/awstats.pl?urlfilter=&urlfilterex=[code]&output=urlentry&config=[config]&year=2006&month=all
http://[host]//awstats.pl?urlfilter=[code]&urlfilterex=&output=urlentry&config=[config]&year=2006&month=all
http://[host]/awstats.pl?hostfilter=[code]&hostfilterex=&output=allhosts&config=[config]&year=2006&month=all
http://[host]/awstats.pl?hostfilter=&hostfilterex=[code]&output=allhosts&config=[config]&year=2006&month=all

The "diricons" parameter is reportedly also affected.

2) The problem is that it is possible to disclose the full path to the installation by supplying an invalid "config" parameter to "awstats.pl".

3) Certain input passed to awstats.pl is not properly verified before being used to redirect users. This can be exploited to redirect a user to an arbitrary website e.g. when a user clicks a specially crafted link to the affected script hosted on a trusted domain.

Vulnerabilities #1 and #2 are confirmed in version 6.5 and vulnerability #3 is reported in versions prior to 6.95.

Solution
Update to version 6.95.

Provided and/or discovered by
1, 2) r0t
3) Reported by the vendor.

Additional information for vulnerability #1 provided by OS Reviews.

Changelog
Further details available to Secunia VIM customers

Original Advisory
AWStats:
http://awstats.sourceforge.net/docs/awstats_changelog.txt

r0t:
http://pridels.blogspot.com/2006/04/awstats-65-vuln.html
http://pridels.blogspot.com/2006/04/awstats-65x-multiple-vuln.html

OS Reviews:
http://www.osreviews.net/reviews/comm/awstats

Deep Links
Links available to Secunia VIM customers