Honeynet Delineates Web Application Threats

An anonymous reader sends us to a technical white paper written by the Honeynet Project & Research Alliance: Know Your Enemy: Web Application Threats. Based on analysis of malware collected by the project, the paper outlines a number of HTTP-based attacks against web applications and some ways of protecting Web servers. Included are code injection, remote code-inclusion, SQL injection, cross-site scripting, and exploitation of the PHPShell application.

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[Beryllium Sphere(tm)]

It's a good article for people who aren't focusing on security professionally. It shouldn't be news to anybody who keeps up with trends, though -- is anyone really still using register_globals?!

Michal Zalewski pointed out a cute hack some years ago. Search engine spiders have to follow links that end in queries, like "toparticle.php?page=1". Barring extraordinary and ultimately impossible care in the coding of the spiders, they could also follow URLs that include attack code after the question mark. In _Silence on the Wire_, he imagined a crook building a long list of links to potentially vulnerable systems, appending attack code to each, and leaving the list someplace where Googlebot and its colleagues will find it. Googlebot could twist the doorknob on 1.5 million PHPBB systems a lot faster than the crook possibly could.

Compromised server

[tttonyyy]

Unfortunately I know about this all too well, the hard way.

Take your eye off the ball and lose your server, it's as simple as that.

If you have a server with a lot of PHP applications running, you need to watch them all. I forgot about a CMS installation on my server that was being preserved for historical reasons (not even linked from the front page, but obviously visible to google), and sure enough, it got exploited via a remote inclusion attack and was used for nefarious perposes for a while without being noticing.

Checking the logs, the definite path of attack was a google for a known vunerable version of the CMS system, and then application of a perl script to perform the hack. Clearly the vunerable system goes into a database of known vunerable systems that gets shared, because to this day, despite the CMS system being backed up and taken offline, my server get attacks about once every 20 minutes from perl scripts targeting that CMS.

I also regularly see bots automatically filling in registration forms with spam, and wikis getting referrer comments added to them or even the content changed by bots.

Looking after even a smallish webserver has proven to be a royal pain in the proverbial.

Regarding PHPShell, I'd hope most people hash their password in the config file rather than leaving it plain-text, and also hide it away somewhere non-obvious (maybe behind another level of protection to keep the webcrawlers from spotting it). But even with hashed passwords, logging in still uses a plaintext password, and is thus equally vunerable to good old ftp and telnet password sniffing. The Joomla extension to provide a plugin PHPShell is a worrying development, and I'm sure will lead to more PHPShell discoveries on servers.

Really the only way to avoid being compromised if you have a semi-busy site, is to learn how to compromise websites yourself, and try it on your own site (and it also teachs you what to look out for in logs). This in combination with regular patching seems to be the best way to stay one step ahead.

And yes, keeping the evidence is good - it gets stupid kids kicked off their ISPs when you send them the proof. ;) Now *that* is some satisfying karma. :)