Caleb Cushing's Blog

Beware of SQL injection with Spring Boot and Flyway

So this is a hard to accomplish exploit, and is really only accomplishable by first exploiting another exploit first, or by an employee with some level of trusted access, though this employee might not normally have actual database access. I do believe you should be aware of it, as it leaves open an avenue you may not be thinking of. A sample application So the first thing we need is an application that uses Flyway, let’s just use the Spring Boot Flyway Sample. Read more →

From Perl to Java

What’s next This is my last post that targets IronMan. So if you want to keep reading my blog, which will probably argely be a mix of security, and java with occasional dev ops, please subscribe directly. If you have suggestions for what categories I should collect things under fee free to comment. Currently the only for sure category is Security. Why not Perl? This post is 3 years in the making. Read more →

Log (CRLF) Injection with SLF4J

At my job we have a CIO installed policy of remediating issues found by a static analysis tool and what it finds are most targeted at finding security issues. Currently this tool is Veracode, and I don’t recommend it, it misses more problems than it finds, and what it finds, including this issue, are often false positives. Our most common issue, is CRLF (Carriage Return Line Feed) or other log injection, which we have mitigated in a custom log appender (which Veracode doesn’t recognize). Read more →

Single Repository, one Aggregate

A Repository as defined in Domain Driven Design manages a single Aggregate. An aggregate may contain many entities, and value objects, but will have a single object as its root. Many of the Dao and even now some of the Repository implementations I see do not follow this, they are more likely to have a Repository per entity, than a Repository per aggregate, and of course in some cases this is required for various reasons. Read more →

Continuous Integration with Wercker and Maven

I’m going to walk you through getting mvn test running in wercker, on the new docker based api. First let’s talk about what Wercker is and why you’d want to use it. Wercker a continuous integration and deployment web application. It will all you to run any language or stack. It currently is free for both private and public repositories; I am hopeful that once it comes out of beta it will maintain reasonable pricing for small personal private projects (Most CI’s are ridiculously priced for hobby projects). Read more →

10 ways of implementing Polymorphism

Firstly what is Polymorphism and why is it so important? Polymorphism is the ability to have a many implementations of a behavior that conform to a single interface. Put in perhaps slightly better, pragmatic terms, you have one implementations of a caller, that can operate on many implementations of a “parameter”, without conditionals, or changing the callers code. For instance the following, pseudo?, Perl 6-ism method handler( $obj ) { $obj. Read more →

Java Privacy, broken by design

It is worth noting that none of the following arguments apply to anything using the keyword static which makes things more procedural (or in some cases functional, than Object Oriented. The suggestion in Java is to give the least required permission, but this, in my humble opinion, violates the Open-Closed Principle. Java has four privacy levels. Giving something the least permission required to function is fine in a Security context, privacy in programming however is simply there to discourage developers from doing stupid things. Read more →

Matching Hex characters in a Regex

I’ve noticed a common problem with regular expressions and Hex Characters, so I thought I’d blog about it. The most common way to regex a UUID, or SHA1 or some other hex encoded binary value is this (and I’ve seen this in Perl libraries and StackOverflow answers). [a-f0-9] or [A-F0-9] Neither of these are correct as Hex is case insensitive and both of these regex’s are. Hex is most commonly lowercase (unless you’re Data::UUID), but that’s an aesthetic, not a requirement. Read more →