Tracking a P2P network related to TA505

This post is by Nikolaos Pantazopoulos and Michael Sandee tl;dr – Executive Summary For the past few months NCC Group has been closely tracking the operations of TA505 and the development of their various projects (e.g. Clop). During this research we encountered a number of binary files that we have attributed to the developer(s) of … Continue reading Tracking a P2P network related to TA505 →

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 →

TA505: A Brief History Of Their Time

Threat Intel Analyst: Antonis Terefos (@Tera0017)Data Scientist: Anne Postma (@A_Postma) 1. Introduction TA505 is a sophisticated and innovative threat actor, with plenty of cybercrime experience, that engages in targeted attacks across multiple sectors and geographies for financial gain. Over time, TA505 evolved from a lesser partner to a mature, self-subsisting and versatile crime operation with … Continue reading TA505: A Brief History Of Their Time →

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 →

Machine learning from idea to reality: a PowerShell case study

Detecting both ‘offensive’ and obfuscated PowerShell scripts in Splunk using Windows Event Log 4104 Author: Joost Jansen This blog provides a ‘look behind the scenes’ at the RIFT Data Science team and describes the process of moving from the need or an idea for research towards models that can be used in practice. More specifically, … Continue reading Machine learning from idea to reality: a PowerShell case study →

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) →

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 →