Recent content on MWLab
Recently I noticed the news about AI-generated malware which was hidden in images with pandas. While the main purpose of the malware is “only” cryptomining, it uses several interesting techniques which are not so common for coinminers. It uses nicely formatted and commented setup script (generated by AI). It supports wide variety of coinminers for various cryptocurrencies and for GPU…
Recent TryHackMe room called “Block” inspired me to create this write-up. The task is to decrypt SMB3-encrypted communication. It turned out that sometimes we only need the captured network traffic to fulfill this task, while otherwise we need some additional info, such as user’s password or its NTLM hash. In this blog post, I would like to summarize three different approaches…
When I looked on recent public submissions on Any.Run this week, my attention was attracted by XWorm samples with tags “stegocampaign”. Quick review of analysis reports reveal simple, yet interesting infection chain. It contains Visual Basic script, PowerShell script, picture with Base64-encoded executable and the XWorm RAT itself. Those payloads have been downloaded from online…
Between 1st-3rd November 2023, there was another CTF event - EKOPARTY CTF. It was a part of the EKOPARTY Security Conference in Buenos Aires, but the CTF was also available online. It was in real Retro theme with IRC and Gopher server. One challenge by Kaspersky was especially interesting for me - network traffic analysis, exploitation, malware and reverse engineering. I would like to share my…
During the October 2023, I participated in the Huntress Capture the Flag contest. It started with couple of warmups challenges on the first day. Then they published two or one challenge every day. There were various categories, such as Warmups, Malware, Forensics, OSINT, Miscellaneous and Steganography. The difficulty levels differs from easy (usually very easy), medium (usually easy, but…
Yesterday, as a part of a challenge in one CTF competition, I had to analyze a modified sample of AsyncRAT. I will try to avoid any spoilers, however, I wanted to decode and decrypt strings from AsyncRAT configuration settings. AsyncRAT is written in C#, and there are various variants and clones in the wild, such as DcRat or VenomRAT. Some samples are almost not obfuscated (except the encryption…
Last month I had two lectures about cyber attacks at Gamefair 2023 conference. And what could be a better practical demonstration than exploitation of a very famous game, which would lead to an encryption of a game server with ransomware? I decided to leverage the two years old vulnerability CVE-2021-44228 (a.k.a Log4shell) in Java Log4j library. This library is also part of the Minecraft Java…
Note: my article was originally published on IstroSec blog In the second part of our overview we continue with the selection of the most used and most usable malware analysis tools. Moreover, we select the tools which are freely available. This time, we focus on tools for analysis other types of the files instead of the native binaries from the previous blog. Wireshark Wireshark is the well known…
Poznámka: tento môj článok pôvodne vyšiel na blogu firmy IstroSec V druhej častí nášho prehľadu prinášame pokračovanie výberu z najpoužívanejších a najužitočnejších nástrojov na analýzu malvéru, ktoré sú navyše k dispozícii bezplatne. Tentoraz sa zameriame aj na nástroje užitočné aj pri iných typoch súborov, než sú tradičné spustiteľné programy. Wireshark Wireshark je veľmi dobre známy nástroj na…
Note: my article was originally published on IstroSec blog In this overview we introduce the selection of the most used and most usable malware analysis tools. Moreover, we select the tools which are freely available. Malware analysis conststs of several phases, starting with extraction and investigation of basic info based on malware sample’s metadata, continuing with behavioral analysis…
Poznámka: tento môj článok pôvodne vyšiel na blogu firmy IstroSec V tomto prehľade prinášame výber z najpoužívanejších a najužitočnejších nástrojov na analýzu malvéru, ktoré sú navyše k dispozícii bezplatne. Analýza malvéru pozostáva z viacerých krokov, od zisťovania základných informácií založených na metadátach analyzovanej vzorky, cez (behaviorálnu) analýzu správania až po debugovanie a…
Attackers compromised up to 1500 companies during massive ransomware attack, which is now reported as one of the largest cyber attacks ever. Victims have been infected with REvil ransomware, which is similar to DarkSide ransomware used recently in Colonial Pipeline attack. However, this time, the deployed REvil ransomware was more obfuscated than versions observed in beginning of 2021. In this…
DarkSide Ransomware is a very hot topic now, especially after the Compromise of Colonial Pipeline networks, which has been investigated by FBI, too. It caused so serious problems that even hackers said that they “didn’t mean to create problems”. However, DarkSide ransomware is not something completely new, and it is similar to the infamous Revil/Sodinokibi ransomware. In this…
Threat intelligence is one of the most critical weapons we can use in cyber defense. I often use Threat intelligence for enhancing my daily tasks in LIFARS such as incident response, threat hunting, forensics and malware analysis. And because the automation is the key for many tasks, I decided to design a new tool which helps us to speedup our processes. Our great R&D team then developed this tool…
IDA, the Interactive Disassembler, is well known tool. It also comes in Freeware version, however, there are several limitations. For example, it is known, that IDA Freeware doesn’t support IDA Python, scripting language which brings the best from the IDA and from the Python world. For scripting, IDA Freeware supports only IDC, a “toy” [2] C-like language. In past I was wondering…
Few weeks ago, I saw somewhere on the Internet question about IDA Freeware compatibility with the Fluorescence plugin. And because this plugin is written in IDAPython and IDAPython isn’t officially supported by IDA Freeware, also this plugin isn’t compatible. However, when I checked what this plugin does, it turns out that it is very simple - its purpose is to highlight call…
In June, LIFARS team worked on engagement related to FIN6 threat actor. FIN6 group was also detected and described in April and May, by various other forensics firms, including SentinelOne and FireEye Managed Defense (Mandiant), which described intrusion by FIN6 threat actor and their latest tactics, techniques, and procedures (TTPs). In particular, they used also LockerGoga and Ryuk ransomware…
In my recent post about XMRig-based CoinMiners spread by Blue Mockingbird Group based mainly on Case Study by LIFARS I wrote about multi-stage attack performed by this threat actor. However, this case study doesn’t contain lot of IOCs (one reason could be to maintain privacy of the victims), and when I want to analyze these samples, first I have to find them somewhere. In this post I…
As I stated in the post about Synology in VirtualBox, I wondered about forensic analysis of Synology NAS, especially about memory acquisition. As a part of preparation phase, I had to figure out how to create a Synology VM, because I did not have access to real Synology HW. Then I found the way how to create a memory dump in DSM 6.1.7 (from May 2018), but I wanted to verify my approach also in…
Overview During March-May the Blue Mockingbird group infected thousands of computer systems, mainly in the enterprise environment. There are known incidents in which they exploited the CVE-2019-18935 vulnerability in Telerik Web UI for ASP.NET, then they used various backdoors and finally, they deployed XMRig-based CoinMiners for mining Monero cryptocurrency. Interesting about these cases is the…
Background A few days ago, we detected a PDF file with a non-zero detection score on VirusTotal, however, almost all the detections have only a kind of “generic” results. Moreover, further investigation revealed that the same file was two weeks ago without any detections on VirusTotal. We continued with a deeper analysis of this document and its behavior to determine if this is only a…
I wondered about forensic analysis of Synology NAS, especially how to create a memory dump, but unfortunately, I was not able to find any useful howtos. I had to try it myself, but as a 1st step I needed a running instance of Synology DSM (DiskStation Manager, the web-based OS running on Synology NAS). Because I do not have any real HW Synology NAS, I decided to try it as a Virtual Machine.
Some people asked me what tools can be useful for Incident Response and for the CSIRT/CERT teams, so I decided to prepare list of such tools and seize the opportunity of the Open Source Weekend in Košice, Slovakia on 19th October. The motivation behind this list is help to enthusiasts and new teams to prepare and/or strengthen technical equipment needed for incident response with minimal costs. On…
Few weeks ago I prepared the technical background of the CTF (Capture the Flag) for QuBit Conference Sofia 2019. It was intedned as a contest in which the three most successful participants will get the opportunity to attend QuBit Conference Sofia 2019. The content itself consisted of 10 challenges divided in 5 categories. In this post will be sumarized the thoughts, ideas and hints about the…
Introduction In the post about GandCrab String Decryption I use very simple heuristic for identifying the function for string decryption. Because this kind of funtion is usually heavily used, I made an assumption that the scting decryption function is the most used function in our sample. This assumption is correct for GandCrab v5.1 DLL files, but it turns out that it is not true for GandCrab v5.2…
Introduction In the last arcitle about Ursnif campaign have been presented the ursnif powershell downloader, which was also able to download the GandCrab payload. This payload was injected as DLL library into the running process and during the last analysis I have extracted it. Now, it is time to look more closely at this GandCrab sample. Obfuscated strings After a quick look at the disassembly we…
Introduction In the first part of this analysis have been presented the two types of macro-enabled documents with powershell downloader spreading via emails in recent campaign. The powershell downloaders and/or the macros were slightly obfuscated, however, it was easy to defeat this obfuscation and reveal their purpose. Unfortunately, during my analysis the downloaded content was not present on…
Overview During the first half of February 2019 there was an increase in occurrences of the Spam messages containing attached documents with the names in the form “Request” followed by the number, like “Request15.doc”. These documents contain slightly obfuscated macros which lead to execution of the PowerShell downloader. This PowerShell downloader connects to the domains…
Introduction My friend have got one USB stick infected with malware, at least that’s what one AntiVirus product reported about it. But strange thing happen, it seemed that the detected file was not present on this USB key. Not only the detected file, but also all of the user data was missing. Only one .lnk file was present in the root of the filesystem. So, this is point where our…
Contact Twitter: @ladislav_b @malwarelab_eu Mastodon: @malwarelab_eu@infosec.exchange Nostr: npub1ksxp2k6449prsqz6e3uq4k87hzw64v6c6u7zqdw9u99ev2y7gfpsnh07l5 LinkedIn: ladislav-baco Author Ladislav Baco is a Senior Security Consultant, Malware Analyst and Network Analyst, with more than 10 years of experience in computer security, computer science and education. Currently he works as a Network…