Authored by Erik Schamper Data acquisition during incident response engagements is always a big exercise, both for us and our clients. It’s rarely smooth sailing, and we usually encounter a hiccup or two. Fox-IT’s approach to enterprise scale incident response for the past few years has been to collect small forensic artefact packages using our … Continue reading I’m in your hypervisor, collecting your evidence
Author: Fox IT
TA505 exploits SolarWinds Serv-U vulnerability (CVE-2021-35211) for initial access
NCC Group’s global Cyber Incident Response Team have observed an increase in Clop ransomware victims in the past weeks. The surge can be traced back to a vulnerability in SolarWinds Serv-U that is being abused by the TA505 threat actor. TA505 is a known cybercrime threat actor, who is known for extortion attacks using the … Continue reading TA505 exploits SolarWinds Serv-U vulnerability (CVE-2021-35211) for initial access
Reverse engineering and decrypting CyberArk vault credential files
Author: Jelle Vergeer This blog will be a technical deep-dive into CyberArk credential files and how the credentials stored in these files are encrypted and decrypted. I discovered it was possible to reverse engineer the encryption and key generation algorithms and decrypt the encrypted vault password. I also provide a python implementation to decrypt the … Continue reading Reverse engineering and decrypting CyberArk vault credential files
Decrypting OpenSSH sessions for fun and profit
Author: Jelle Vergeer Introduction A while ago we had a forensics case in which a Linux server was compromised and a modified OpenSSH binary was loaded into the memory of a webserver. The modified OpenSSH binary was used as a backdoor to the system for the attackers. The customer had pcaps and a hypervisor snapshot … Continue reading Decrypting OpenSSH sessions for fun and profit
StreamDivert: Relaying (specific) network connections
Author: Jelle Vergeer The first part of this blog will be the story of how this tool found its way into existence, the problems we faced and the thought process followed. The second part will be a more technical deep dive into the tool itself, how to use it, and how it works. Storytime About … Continue reading StreamDivert: Relaying (specific) network connections
A Second Look at CVE-2019-19781 (Citrix NetScaler / ADC)
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)
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
Office 365: prone to security breaches?
Author: Willem Zeeman "Office 365 again?". At the Forensics and Incident Response department of Fox-IT, this is heard often. Office 365 breach investigations are common at our department. You’ll find that this blog post actually doesn’t make a case for Office 365 being inherently insecure – rather, it discusses some of the predictability of Office … Continue reading Office 365: prone to security breaches?
Using Anomaly Detection to find malicious domains
Applying unsupervised machine learning to find ‘randomly generated domains. Authors: Ruud van Luijk and Anne Postma At Fox-IT we perform a variety of research and investigation projects to detect malicious activity to improve the service of our Security Operations Center. One of these areas is applying data science techniques to real world data in real … Continue reading Using Anomaly Detection to find malicious domains