iframe attacks are pretty old actually, while the method in which they're impletmented varies, the effect is the same. To gain control of a wide array of site pages at once and launch a form of spyware, adware, malware or whatever else junk they want from the page rendering using another form of Zero day hole in something like your browser.
You really need to setup mod_security on your server with a custom ruleset. The exploit string in which you posted is really really old. Basically the attackers using a php include on a remote file that runs as if it were part of the code on the users page.
Any clients machines I secure and configure haven't been affected by this so it must be related to a few different things.
1) The attacker finds a hole in your users local PHP script
2) The inject their own PHP code from a remote file making it run as if they uploade the page by regular FTP.
3) There are numerous ways you can easily collect the usernames of accounts, very very very easy.
4) You can start to then brute guess passwords of user accounts
5) You can then start scouring the server for local exploits and use them to your advantage. EG: The script you metioned in that include checks to see if wget, gcc and other system binaries are on the system and asssible for the attacker to use.
6) With a list of whats installed and what they can use, they can now download hacks and start trying to crack your machine and compiling code attempting to gain root, etc.
7) They can search any and all 777 permission files/directories and inject whatever they feel like. Good times for them, crappy time for the site owners and server owners to clean up the mess.
Preventing this is a combination of things that I won't go into complete details about but I'll brief over so you get the idea.
1) Lock your system binaries, like wget, gcc, and others to stop anyone from using them.
2) Secure PHP by disabling functions used such as: proc_open, exec, system, passthru and so on.
3) Make sure PHP/Apache is up to date
4) Install mod_security and have CURRENT ruleset! Mod_security through cPanel install has NO ruleset! I have rulesets I give all my clients which are tried, tested and true.
5) Have a current kernel installed, there are many exploits that still work on a lot of providers.
There are tons you can do to help lock your machine. If you don't know, then hire someone that's what we're here for, besides our good looks of course :D
