Authors: Rich Warren of NCC Group FSAS & Yun Zheng Hu of Fox-IT, in close collaboration with Fox-IT’s RIFT. About the Research and Intelligence Fusion Team (RIFT): RIFT leverages our strategic analysis, data science, and threat hunting capabilities to create actionable threat intelligence, ranging from IOCs and detection capabilities to strategic reports on tomorrow’s threat … Continue reading A Second Look at CVE-2019-19781 (Citrix NetScaler / ADC)
Category: Uncategorized
LDAPFragger: Command and Control over LDAP attributes
Written by Rindert Kramer Introduction A while back during a penetration test of an internal network, we encountered physically segmented networks. These networks contained workstations joined to the same Active Directory domain, however only one network segment could connect to the internet. To control workstations in both segments remotely with Cobalt Strike, we built a … Continue reading LDAPFragger: Command and Control over LDAP attributes
Hunting for beacons
Author: Ruud van Luijk Attacks need to have a form of communication with their victim machines, also known as Command and Control (C2) [1]. This can be in the form of a continuous connection or connect the victim machine directly. However, it’s convenient to have the victim machine connect to you. In other words: It … Continue reading Hunting for beacons
Detecting random filenames using (un)supervised machine learning
Combining both n-grams and random forest models to detect malicious activity. Author: Haroen Bashir An essential part of Managed Detection and Response at Fox-IT is the Security Operations Center. This is our frontline for detecting and analyzing possible threats. Our Security Operations Center brings together the best in human and machine analysis and we continually … Continue reading Detecting random filenames using (un)supervised machine learning
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
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
Introducing Orchestrator decryption tool
Researched and written by Donny Maasland and Rindert Kramer Introduction During penetration tests we sometimes encounter servers running software that use sensitive information as part of the underlying process, such as Microsoft's System Center Orchestrator. According to Microsoft, Orchestrator is a workflow management solution for data centers and can be used to automate the creation, … Continue reading Introducing Orchestrator decryption tool