I work with really old technology which takes ages to create websites. The security is also bad (tons of vulnerabilities such as XSS, CSRF...).
How do I change to a better situation? The guy who makes the decision in IT does not want to listen. He is proud of what he did; he made those websites.
The site is actually base on a big system that our boss want to sell to others developers (not in house) which will be terrible for that company since it's not coding well. I personaly don't care, but since the boss is a good guy and has no idea what's going on behind the scene, I feel bad. It took them 3 years to make this system. In my previous company, we did the exact same thing within 4 months using the latest technologies. I already suggest to use "new cool stuff" and fix security issues, but I just got ignored because I'm the "new guy" here.
EDIT
Thanks a lot guys for your answers. It a lot more clear now and helped me a lot. @jmac, for answer to your really interesting topic :
Understand the current system : I already spent over 8 months working with it. The thing is, this project (as all the other projects we are doing) have no plans or structure at all. When we start a new project, we basically receive an email saying "Make this project please". We don't have any project manager (that is also a part of the problem). On my hand, I'm trying to get the maximum of information and plan before start to code. The other guy (the developer who takes the decision), let's call him X, jump on the code right away without even thinking how he gonna do it. That's why the current system sucks. It's basically a website, but since this website get a lot of visitors, they simply thought "Oh this thing is great, let's turn it into a big engine we can resuse and sale".
Don't criticize/condemn/complain : Here again, I didn't say at all "It sucks..." for the same reasons you mentionned. I know being negative can for sure push poeple to be negative as well. First time, I wanted to give X some suggestions about the UI/UX on the website and I told him over an email (there's no real communication here, we talk through a chat or email) : "Hey, I may have some UI/UX suggestions that I think could be great in order to give our visitors a better navigation on our website". X simply ignored me. He didn't even answer.
Build trust : That's the part I don't really have now. I'm new, yeah, but I also need to work with this messy "engine". They already told me, that they want to keep me because they are satisfied of what I did so far. The thing is, the only time, I was asked to create a new website from scratch on my own, they again told me : "You have to use this X and Z tools". In all my previous work in the past, one of the main aspect for any projects was productivity. So I was use to work with productive tool. I'm frustrated to have to write 100 lines of code with the current tool, when I can write the same thing using 30 lines with another tool. I also already show them this gain of productivity, but again, I was ignored.
Clearly outline the benefits of any change : Thanks for this point as I'm gonna work on that to explain all my arguments.