HTTP Header Injection vulnerabilities occur when user input is insecurely included within server responses headers. Specifically they are based around the idea that an attacker can cause the server to generate a response which includes carriage-return and line-feed characters (or %0D and %0A respectively in their URI encoded forms) within the server response header the attacker may be able to add crafted headers themselves. Header Injection can allow for attacks such as response splitting, session fixation, cross-site scripting, and malicious redirection.
I posted a while ago on the very basics of SQL Injection. Then after than I did a complete breakdown of the manual exploitation of SQL Injection. Armed with that post and a cheatsheet or two, you should be able to get knee deep in almost any injection point. However, the truth is that often these injection points can be exploited using free, publicly available tools such as SQLmap! SQL injection can be a time consuming thing to exploit, especially when it comes to blind or out-of-band injection! So why not take the path of least resistance and automate wherever you can.
A friend of mine mentioned recently that he has to work out subnet masks in his head for an exam and commented in reality he’d just use a subnet calculator. Whilst this is probably true, there’s a quick trick that might help if you’re calculating subnets under duress. This isn’t a full write up and offers no real explanation of why it works, it’s just pointing out a trick you may have missed which might come in handy one day!