A Deep Dive into the World of DOS Viruses

Dive deep into the world of DOS viruses in this 38-minute conference talk from the 35th Chaos Communication Congress (35C3). Explore the inner workings of COM file infections that plagued systems during the MS-DOS era. Learn about the basics of IBM PC architecture, MS-DOS execution, and binary runtime. Discover how modern analysis methods and community archives are used to uncover the mechanisms of these historical threats. Follow along as the speaker dissects famous payloads, explains automatic tooling for mass malware analysis, and highlights interesting samples from over 17,000 archived viruses. Gain insights into how malware has evolved over the past 27 years, from the days of MS-DOS 5.0 to present-day threats. No prior reverse engineering skills are required to appreciate this comprehensive look at a fascinating chapter in computer security history.

Intro
Welcome
What is DOS
DOS viruses
Nav Rage example
Segment registers
A smoking gun
Finding the code
Examples
Questions