Tag Archives: Security

CVE-2019-17556: Unsafe deserialization in Apache Olingo

Some time ago I wrote about one security issue which I found in the library. This post describes another little vulnerability in Apache Olingo. The issue has been fixed in the 4.7.0 release as well.

By the way, Apache Olingo is a Java library that implements the Open Data Protocol (OData). This protocol allows the creation and consumption of queryable and interoperable RESTful APIs in a simple way.

CVE-2019-17556: Unsafe deserialization in Apache Olingo
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CVE-2019-17555: DoS via Retry-After header in Apache Olingo

Apache Olingo is a Java library that implements the Open Data Protocol (OData). This protocol allows the creation and consumption of queryable and interoperable RESTful APIs in a simple way.

This post describes a little vulnerability that I recently discovered in Apache Olingo. The issue has been fixed in the 4.7.0 release.

CVE-2019-17555: DoS via Retry-After header in Apache Olingo
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Safer deserialization in Spring Security OAuth2

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.

Safer deserialization in Spring Security OAuth 2.4.0
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CVE-2019-12415: XML processing vulnerability in Apache POI

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.

CVE-2019-12415: XML processing vulnerability in Apache POI
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Safer deserialization with new Jackson 2.10

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.

Safer deserialization with new Jackson 2.10
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TLS enhancements in Java 13

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.

TLS enhancements in Java 13
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Security testing for REST API with w3af

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.

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Configuring security for REST API in Spring

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.

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What’s new security features in Java 11?

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
  • Unicode 10
  • deprecating Nashorn JavaScript Engine and Pack200 tool
  • 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.

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