mkYARA – Writing YARA rules for the lazy analyst

Writing YARA rules based on executable code within malware can be a tedious task. An analyst cannot simply copy and paste raw executable code into a YARA rule, because this code contains variable values, such as memory addresses and offsets. The analyst has to disassemble the code and wildcard all the pieces in the code … Continue reading mkYARA – Writing YARA rules for the lazy analyst →

PsiXBot: The Evolution Of A Modular .NET Bot

PsiXBot: The Evolution Of A Modular .NET Bot Summary In this blog we will share our analysis of a modular piece of malware which is referred to by the author as PsiXBot. The malware first surfaced in 2017 but has recently undergone significant developments of its core and modules, which include the logging of keystrokes … Continue reading PsiXBot: The Evolution Of A Modular .NET Bot →

Identifying Cobalt Strike team servers in the wild

How an anomalous space led to fingerprinting Summary On the 2nd of January 2019 Cobalt Strike version 3.13 was released, which contained a fix for an "extraneous space". This uncommon whitespace in its server responses represents one of the characteristics Fox-IT has been leveraging to identify Cobalt Strike Servers, with high confidence, for the past … Continue reading Identifying Cobalt Strike team servers in the wild →

Your trust, our signature

Written and researched by Mark Bregman and Rindert Kramer Sending signed phishing emails Every organisation, whatever its size, will encounter phishing emails sooner or later. While the number of phishing attacks is increasing every day, the way in which phishing is used within a cyber-attack has not changed: an attacker comes up with a scenario … Continue reading Your trust, our signature →

Phishing – Ask and ye shall receive

During penetration tests, our primary goal is to identify the difference in paths that can be used to obtain the goal(s) as agreed upon with our customers. This often succeeds due to insufficient hardening, lack of awareness or poor password hygiene. Sometimes we do get access to a resource, but do not have access to … Continue reading Phishing – Ask and ye shall receive →

Introducing Team Foundation Server decryption tool

During penetration tests we sometimes encounter servers running software that use sensitive information as part of the underlying process, such as Microsoft's Team Foundation Server (TFS). TFS can be used for developing code, version control and automatic deployment to target systems. This blogpost provides two tools to decrypt sensitive information that is stored in the TFS … Continue reading Introducing Team Foundation Server decryption tool →