Windows

Prompt response to ransomwares

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Automation is one of the key elements of a modern Security Operation Center. In a traditional SOC without any automation, analysts have to spend a lot of time on tedious and repetitive tasks. This is really inefficient in multiple ways. The analysts can’t use their skills, they must do something that a simple program could do as well. Also, doing things manually can significantly increase the time between starting an investigation and successfully resolving an incident.
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Hunters after ransomwares

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Ransomware is one of the biggest buzzwords nowadays in security. Vendors are advertising their security products by telling it can stop ransomwares, but also on the other side of the field, ransomwares, ransomware kits or services are selling pretty well. Over the last year, one could read an article every month about how ransomwares are not relevant now but also about the rising and more and more sophisticated ransomware attacks.
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How (not) to log DNS traffic

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Companies tend to create their security detections based on the trending behavior of threat actors. One of the constantly re-occurring techniques is DNS-based activities like exfiltration via DNS (Domain Name System) or C2 (Command and Control) communication via DNS. Still, a lot of companies are lacking in DNS logging, missing DNS-based detection rules, or not aware of their own blindspots. In this post I’m not trying to explain how to detect DNS-based techniques.
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Unremovable malware with WSL

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Windows Subsystem for Linux (or, as I’m incorrectly calling it, Linux Subsystem for Windows) is a tool in Windows 10 that provides a Linux kernel on top of the Windows kernel. WSL can translate Linux system calls to Windows language. This way one can execute Linux-related apps/commands in Windows without re-compilation. It can be powerful in the hand of a good administrator but it also has some drawbacks as it was mentioned in this reddit post: https://www.
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Defcon DFIR CTF 2019 writeup - Triage VM

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This year an unofficial Defcon DFIR CTF was provided by Champlain College’s Digital Forensic Association. They created challenges in 5 topics which are available for anyone for a little practice on this site: defcon2019.ctfd.io. The challenges are sorted into the following categories: DFA Crypto Challenge Deadbox Forensics Linux Forensics Memory Forensics Triage VM Questions I’m pretty new in forensics, started my journey approximately 9 months ago and have been doing it as an active hobby for 6 months now.
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USB storage forensics in Win10 #1 - Events

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Having information about USB devices connected to a system can be essential for some investigations and analyses. Most of the removable storages used nowadays are USB pen drives so knowing how to identify and investigate these is crucial. The main purpose of USB drive forensic analysis is to identify the connected devices and find some of the following information about it: connection and removal time, files copied to or from the device, opened and executed files and software from the attached drive.
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Malicious process analyzer

I have recently started to make some basic research with osquery. I investigated some malware infections in the past and I decided that I’m going to take a look at them with osquery as well. I was curious how much data I can retrieve with osquery and how much I will benefit from its usage. I was honestly surprised because it helped me make some basic information gathering faster than my earlier methods.
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DNS investigation on Windows

Recently, a friend of mine has asked for my help in an investigation. In his SIEM system, he saw that a machine generated some DNS sinkhole events, but he couldn’t find the originally requested DNS by the host. The events were generated because the machine tried to resolve a DNS hostname which was marked as malicious in the DNS Server. Unfortunately due to the huge amount of DNS requests in a network, this company did not store the DNS events in the SIEM.
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NTFS Timestamp changes on Windows 10

During my File System Tunneling related investigation I tested NTFS timestamp changes in case of different operations on Windows 10. I used SANS’s DFPS_FOR500_v4.9_4-19 and Cyberforensicator’s timestamp posters for comparison. I found out that my results were different from theirs. In my tests, some of the operations produced different timestamp changes and inheritance than the previously mentioned posters show. These timestamp rules can change in every Windows version so it is worth checking them from time to time.
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File System Tunneling in Windows

File System Tunneling is a really old feature of Windows. It was already discussed on many security or Windows administration related blogs and books. However, it is still somewhat obscure for lots of examiners because its forensic implication is limited. The simplest way to test and observe it in action is to delete a file and then create a new one with the same name in the same path. The new file is going to inherit the creation timestamp of the original file.
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