The Java standard library provides the ObjectInputStream class which offers a convenient way for deserializing Java objects. Unfortunately, this way is not safe by default. Using this class may open the doors for Java deserialization attacks which in the worse case may result in arbitrary code execution.
I recently discovered that Spring Security OAuth2 library may be vulnerable to such an attack. Fortunately, there is one strong pre-requisite for a successful attack which may be difficult to meet for an adversary. Nevertheless, I thought it might be better to make the library a bit safer, and the project maintainers kindly accepted the contribution. Here are the details.
Apache POI is a popular Java library for working with Microsoft documents. For example, it allows you reading and writing Microsoft Excel files using Java. When I was recently looking into the library, I noticed a little vulnerability which then became CVE-2019-12415. The issue has been fixed in POI 4.1.1. Below are the details.
New Jackson 2.10 was released on Sep 26th, 2019. Everyone who uses the library and also scans their applications for known vulnerabilities knows about the problem with endless CVEs that have been reporting against Jackson. Let’s try to understand what makes an application vulnerable and how the new version of Jackson can help to prevent deserialization vulnerabilities.
Java 13 was released on Sep 13th, 2019. Although the new Java doesn’t contain major updates in security libraries, nevertheless it has several notable updates in the TLS implementation. Let’s take a closer look at how Java 13 helps to make your TLS connections faster and more secure.
Nowadays more and more companies provide web APIs to access their services. They usually follow REST style. Such a RESTful web service looks like a regular web application. It accepts an HTTP request, does some magic, and then replies with an HTTP response. One of the main differences is that the reply doesn’t normally contain HTML to be rendered in a web browser. Instead, the reply usually contains data in a format (for example, JSON or XML) which is easier to process by another application.
Unfortunately, since a RESTful web service is still a web application, it may contain typical security vulnerabilities for web applications such as SQL injections, XXE, etc. One of the ways to identify security issues in web applications is to use web security scanners. Fortunately, since a RESTful web service is still a web application, we can use web security scanners to look for security issues in web APIs.
There are several well-known web security scanners. One of them is w3af created by Andres Riancho. I’ll focus on this scanner in the post.
In most cases, REST APIs should be accessed only by authorized parties. Spring framework provides many ways to configure authentication and authorization for an application. Another good thing is that the framework usually provides relatively good default settings. But nevertheless, it may be better to understand what’s going on rather then rely on the defaults.
This post contains a list of things which may be good to pay attention to when you configure or review authentication and authorization settings for a RESTful application based on Spring (boot) framework. However this is not a comprehensive guideline (if such a guideline even exist) which tells how to configure authentication and authorization for an application based on Spring framework. It’s more like a collection of tips and suggestions. Furthermore, any other suggestions and comments are more than welcome.
Java 11 was released on Sep 25th, 2018. This is the first long-term support release produced under the six-month cadence release model. Besides a huge number of small improvements and bug fixes, the new release contains 17 major enhancements including:
several updates in the Hotspot and garbage collectors
new HTTP client
removing the Java EE and CORBA Modules
local-variable syntax for Lambda parameters
launch single-file source-code programs
and finally several security features
Although all these features are pretty cool, let’s focus on security in this post.
TLS 1.3 standard was finally published in August 2018. The authors tried to address the problems which unfortunately exist in older versions of the TLS protocol. One of the problems is a lack of protection against downgrade attacks.
Code coverage analysis is used in software testing to discover untested pieces of an application. Gathering code coverage data may also be useful for fuzzing. Basically it may help to figure out which parts of a program were not reached during fuzzing. This info can then be used to improve the fuzzer.
Let’s try to gather some code coverage data during fuzzing. As an example, we’re going to test picotls with tlsbunny. Picotls is an implementation of TLS 1.3 protocol written in C, and tlsbunny is a framework for building negative tests and fuzzers for TLS 1.3 implementations. We’re going to use gcov for gathering code coverage data, and lcov for creating a report.