Optimizing Elasticsearch – Part 2: Index Lifecycle Management

In the previous blog post "Optimize Elasticsearch for log collection - Part 1: reduce the number of shards", we have seen one solution to recover a cluster suffering from the "too many shards syndrome" by merging indices that were too small. In this article, we'll see how we can rely on latest Elasticsearch feature to … Continue reading Optimizing Elasticsearch – Part 2: Index Lifecycle Management

Solving a CTF challenge: Exploiting a Buffer Overflow (video)

Capture The Flag (CTF) competitions are an entertaining way to practice and/or improve your skills. NVISO staff regularly participates in CTF competitions, in particular when the competition focuses on IT security. We produced a video with step-by-step analysis of a CTF executable containing a buffer overflow. This executable is running on a server, and by … Continue reading Solving a CTF challenge: Exploiting a Buffer Overflow (video)

Detecting and Analyzing Microsoft Office Online Video

A while ago, a new technique was developed to execute arbitrary code via a Word document: an online video is embedded and the HTML code for the embedded video is modified with JavaScript that launches a Windows executable. This technique does not rely on VBA macros and requires the use of the .docx format (for … Continue reading Detecting and Analyzing Microsoft Office Online Video

Optimizing Elasticsearch for security log collection – part 1: reducing the number of shards

Nowadays, logs collection for security monitoring is about indexing, searching and datalakes; this is why at NVISO we use Elasticsearch for our threat hunting activities. Collecting, aggregating and searching data at a very high speed is challenging in big environment, especially when the flow is bigger than expected. At NVISO, we are constantly seeking for … Continue reading Optimizing Elasticsearch for security log collection – part 1: reducing the number of shards

Azure Security Logging – part 2: security-logging capabilities of Azure resources

In this second blog post in a series about Azure Security Logging, we will focus on some of the key services that are used in most Azure deployments. We go into detail how logging can be enabled, what logging options are available and what relevant data is generated. Log sources in Azure At the moment … Continue reading Azure Security Logging – part 2: security-logging capabilities of Azure resources

Azure Security Logging – part I: defining your logging strategy

In this first blog post in a series about Azure Security Logging, we will give a general overview of the types of logs available for Azure services including their storage options. We will also discuss how to define a security logging strategy in Azure. In the upcoming blog posts, we will go into detail about … Continue reading Azure Security Logging – part I: defining your logging strategy