Half-drunk Review of Mirai Malware

Quick Overview

The Mirai malware source code, leaked in 2016, is described as extremely simple, lacking sophisticated security features like encryption or proper data structure separation, which allowed it to easily compromise IoT devices for DDoS attacks, contrasting sharply with modern malware complexity.

Key Points: The Mirai malware source code, leaked around 2016, is extremely simple, using basic C and Go programming constructs without advanced security measures. The Go source code reveals hardcoded database credentials (e.g., 'root'/'root'/'mirai') and uses an unencrypted MySQL connection string. The C source code in the 'bot' directory shows basic attack functions (UDP, SYN, GRE, etc.) being registered without obfuscation. The author notes that the malware's simplicity (e.g., using hardcoded credentials and no encryption) made it easy to understand but also allowed it to scale quickly, infecting tens of millions of devices. The simplicity extends to the database structure (e.g., 'db' struct in 'database.go' only has a 'val' field) and the lack of complex logic, such as checking for existing agents or using proper encryption for credentials. The scanner component in 'scanner.c' uses hardcoded default ports (like 23 for Telnet) and relies on simple brute-forcing of credentials. The speaker argues that modern malware development, even by security companies, is significantly more complex, suggesting Mirai's approach is now obsolete for avoiding detection.

Context: The video provides a high-level review and code walkthrough of the leaked Mirai botnet source code, which gained notoriety for weaponizing insecure IoT devices to launch massive DDoS attacks starting around 2016. The presenter, a self-described computer nerd, examines the source code files, primarily written in C and Go, to illustrate how rudimentary the malware's structure and security practices were compared to contemporary malicious software.

Detailed Analysis

The video analyzes the source code of the Mirai botnet, highlighting its relative simplicity compared to modern malware. The presenter first looks at the Go source code in the 'c2' directory, noting hardcoded credentials in 'database.go' (like 'root'/'root'/'mirai' for the database) and the direct use of an unencrypted MySQL driver string, demonstrating poor security practices from the start. The logic in 'main.go' is shown to simply spawn goroutines to handle incoming connections. The analysis then shifts to the C source code found in the 'bot' directory, specifically in 'attack.c', which lists numerous hardcoded attack functions (like UDP, SYN, DNS, HTTP floods) that are registered sequentially. The presenter points out that this lack of complexity and obfuscation, combined with the malware's ability to exploit default credentials on IoT devices (as seen in 'scanner.c'), contributed to its massive scale. The speaker concludes that while effective at the time, this simplicity is why Mirai is now considered outdated, as modern defenses and malware development techniques (like complex encryption and better threat modeling) have advanced significantly.