noch lab

1. Overview This article describes the following topics. ・Commandline rewriting technique ・Applying new command line to reflective loaded PE file's context My goal was to develop loader that load PE file from URL and launch PE file in memory with new commandline context. This is stealth since it leaves no final payload on filesystem. Since this is a topic that has been described exhaustively, this post does not describe downloading PE file and reflective load. This article does not show the full code to prevent abuse. 2. Commandline rewriting When this loader starts, loader's commandline is "loader.exe [c2url] [newcommand]". This loader needs to load the PE file into memory and patch memory so that [newcommand] is handled as the first argument. The commandline is included in RTL_USER_PROCESS_PARAMETERS structure, which is pointed to by ProcessParameters member of PEB structure. PEB is very important structure in the process. I believe it will work ...

1. Overview I found a site that distributes curious PDF converter. The executable file distributed at this site appears to be malicious and have several interesting features. ・ .NET Anti-Analysis ・ Execution of external JavaScript payload with WebView2 ・ .NET object manipulation from JavaScript code This post will mention these techniques. The execution flow of this executable is shown below. 2. .NET Anti-Analysis PdfConverters.exe analyzed in this article was created with .NET Core. .NET Core allows developer to embed runtime and libraries into a single executable file. This executable also contains a number of files, which are extracted at execution time into a folder under %TEMP%\PdfConverters. A good way to know the role of these files is to look at [AppName].deps.json. app.deps.json reveals that main functionality of this executable exists in app.dll. [app.deps.json] ... "app/1.0.0": { "dependencies": { "Microsoft....