Now it's time for the write-up. More precisely, the one on Pay TV, their
200 points web challenge.
Pay TV, the challenge
The website is composed of a static image, a gif (the noise on the TV) and
an input text box (a decoder?).
Really simplistic design and not so much to look around, except that noise and
that input field.
When I saw that noise gif for the first time, I was really scared about some
stegano inside.
My thought? Screw you stega, I'm not looking for you. Let's focus on the
rest instead :P
Among my missions in Société Générale, a key
element is to collect information about websites in order to pentest them.
The group Société Générale counts more than 150
000 employees.
It has a really complex organizations, like every big
companies I guess.
Therefore it becomes really hard to have an overall point of view on all its
servers, since they are spreaded across all the group's branches and their
sectors.
That is to say that I have to deal with hundreds, thousands of domain names and
IP addresses, and gathering information about them takes a lot of time.
What we mean by collect information about a website is to identify several
main information like:
The IP address
The domain name
The service running on the machine (web, ssh, dns, etc.)
If there is any load balancing
The sector affiliated to
etc.
In this post, I assume that I only have IP addresses.
During some tests about getting the hostname of an IP address, I had to use
gethostbyaddr.
If you ever tried to use
gethostbyaddr,
you must have seen that it can take long time to answer.
The problem with this function is that it takes a high amount of time
before giving up on the domain name resolution.
Among the thousands of IP addresses, a bunch of them come from ranges reserved
by the SG group.
Not all of them point to a running machine, therefore a lot of them don't have
a host name.
When you can wait like 5 to 10 seconds for 1 or 2 addresses, it is not viable
to wait hours and hours for thousands of them.
Due to maintenance from TonBNC on server9, you might
have seen that the blog was down during these 2 last days.
The maintenance finished Sunday night but for some unknown reason, the
configuration of the network interface disappeared...
The administrators gave me the serial access and I was able to restart it.
From now on, all the services have been successfully restarted.
Too bad that my uptime of 182 days disappeared too :'(
I will spend my next 24 weeks in the company Société
Générale, in their Information Systems Security
service.
Therefore I will have less time for posting stuff around.
I will try to write a paper about the packer stuff though, since the project
progressed substantially this summer.
