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.

Comments

Patch! Patch! Patch!

[gbulmash]

The basic theme of this seems to be "patch! patch! patch!". A lot of the scripts they discussed (AWStats, phpBB, etc.) are ones where the people who use them don't have the expertise to dig into their code and fix problems themselves (or possibly even understand what the problems are).

The three rules of running a web app you didn't write:

• 1: Subscribe to the announcements mailing list
  
• 2: Apply patches immediately
  
• 3: Back-up your shit regularly, because even if you do 1 and 2, you might get hit and then you're going to need your backups.
  

Rule three is sort of universal for any webmaster, whatever they're running, even if they wrote it all themselves and have security certifications up the wazoo. Not running back-ups is about as wise as putting your 401k funds into lottery tickets.

- Greg

Re:Uh . .

[Beryllium Sphere(tm)]

Well, don't use "nobody", use a non-shared account with a name like "www". And chroot won't help you with a SQL injection attack, especially if the scripts log in as "sa" (don't laugh, I've seen it done).

If it's the apps being attacked and not the server, the first line of defense is to sanitize user input.

Re:Related work

[MrTrick]

No-index is not the issue here.

As GP stated, you could publish on any webpage a list of links that contain malicious code in them. When Google, Yahoo, and other spiders crawl the links, *THEY* end up doing the attacking. That is rather dangerous, I'd say - it'd be very difficult to track down the person responsible, especially if the original webpage was posted on a zombie server.

It reminds me of this DailyWTF story: http://worsethanfailure.com/Articles/The_Spider_of _Doom.aspx

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. :)