Then let me be blunt: the level of risk is high, and will grow higher with every new security threat. You are are already vulnerable to
shellshock. With the NTP bug, that makes two high profile security vulnerabilities that you're not patching. It will only grow.
Sitting around, putting your fingers in your ears and saying "I don't know from these newfangled bugs!" and hoping nothing happens to your system isn't going to make the problem go away. If you insist on keeping Snow Leopard on your computer, then you need to learn how to use
Brew or
Macports to figure out how to compile and patch new versions of the low-level packages that run on your computer. That's the price you pay for wanting to run old software on the public Internet.
If that's not something you want to do, then you have other options:
1. Buy and learn VMware Fusion and install Snow Leopard in an isolated container, and run your old software in there while upgrading your main OS.
2. Upgrade and say goodbye to that old software, or
3. Buy an old, beat up Mac and disconnect it from the internet and run your old software that way. Or buy a new Mac with the current OS and use that for your internet usage.
Or you can continue to be willfully ignorant about security threats, in which case, good luck bro. You're gonna need it.