Detecting and Protecting when Remote Desktop Protocol (RDP) is open to the Internet

Category:  Detection/Reduction/Prevention Overview Remote Desktop Protocol (RDP) is how users of Microsoft Windows systems can get a remote desktop on systems remotely to manage one or more workstations and/or servers.  With the increase of organizations opting for remote work, so to has RDP usage over the internet increased. However, RDP was not initially designed with the … Continue reading Detecting and Protecting when Remote Desktop Protocol (RDP) is open to the Internet

Cracking Random Number Generators using Machine Learning – Part 2: Mersenne Twister

Outline 1. Introduction2. How does MT19937 PRNG work?3. Using Neural Networks to model the MT19937 PRNG3.1 Using NN for State Twisting3.1.1 Data Preparation3.1.2 Neural Network Model Design3.1.3 Optimizing the NN Inputs3.1.4 Model Results3.1.5 Model Deep Dive3.1.5.1 Model First Layer Connections3.1.5.2 The Logic Closed-Form from the State Twisting Model Output3.2 Using NN for State Tempering3.2.1 Data Preparation3.2.2 … Continue reading Cracking Random Number Generators using Machine Learning – Part 2: Mersenne Twister

Cracking Random Number Generators using Machine Learning – Part 1: xorshift128

Outline 1. Introduction2. How does xorshift128 PRNG work?3. Neural Networks and XOR gates4. Using Neural Networks to model the xorshift128 PRNG4.1 Neural Network Model Design4.2 Model Results4.3 Model Deep Dive5. Creating a machine-learning-resistant version of xorshift1286. Conclusion 1. Introduction This blog post proposes an approach to crack Pseudo-Random Number Generators (PRNGs) using machine learning. By cracking … Continue reading Cracking Random Number Generators using Machine Learning – Part 1: xorshift128

NCC Group placed first in global 5G Cyber Security Hack competition

In June of this year, Traficom - the Finnish transport and communications agency - along with the Aalto University, Cisco, Ericsson, Nokia, and PwC, organized the 5G Cyber Security Hack competition. A similar event was organised in November 2019 in Oulu, Finland and this hackathon-style event was a follow-up to their successful 2019 event. Due … Continue reading NCC Group placed first in global 5G Cyber Security Hack competition

Paradoxical Compression with Verifiable Delay Functions

We present here a new construction which has no real immediate usefulness, but is a good illustration of a fundamental concept of cryptography, namely that there is a great difference between knowing that some mathematical object exists, and being able to build it in practice. Thus, this construction can be thought of as having some … Continue reading Paradoxical Compression with Verifiable Delay Functions

A Look At Some Real-World Obfuscation Techniques

Among the variety of penetration testing engagements NCC Group delivers, some - often within the gaming industry - require performing the assignment in a blackbox fashion against an obfuscated binary, and the client's priorities revolve more around evaluating the strength of their obfuscation against content protection violations, rather than exercising the application's security boundaries. The … Continue reading A Look At Some Real-World Obfuscation Techniques

The Challenges of Fuzzing 5G Protocols

If you have ever looked at fuzzing in any depth you will quickly realize it’s not as trivial as it first appears. There are many different types of fuzzers, but here we are focused on network fuzzers.  These fuzzers are of particular interest as they are most suited to fuzzing telecoms products/protocols, where the application … Continue reading The Challenges of Fuzzing 5G Protocols

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

Technical Advisory – Open5GS Stack Buffer Overflow During PFCP Session Establishment on UPF (CVE-2021-41794)

Vendor: Open5GS Vendor URL: https://github.com/open5gs/open5gs Versions affected: 1.0.0 to 2.3.3 Systems Affected: Linux Author: mark.tedman[at]nccgroup[dot]com Advisory URL / CVE Identifier: CVE-2021-41794 Risk: CVSSv3.1: 8.2 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H) Summary When connecting to the UPF port for the PFCP protocol (8805) and sending an Association Setup Request followed by a Session Establishment Request with a PDI Network Instance set … Continue reading Technical Advisory – Open5GS Stack Buffer Overflow During PFCP Session Establishment on UPF (CVE-2021-41794)

Assessing the security and privacy of Vaccine Passports

There has been a lot of development lately in the field of health credentials, especially in the field of vaccine credentials. This has largely been driven by a perceived need to track and validate an individual's vaccination status with respect to COVID-19. This post attempts to explore the security and privacy concerns related with vaccine … Continue reading Assessing the security and privacy of Vaccine Passports