Dan Farmer

Early Life and Education

Dan Farmer was born on April 5, 1962. He studied computer science at Purdue University, where he began his career in security research. It was during his time as a student in 1989 that he developed his first significant security software, with guidance from professor Gene Spafford.

Early Career and COPS

Farmer's first major contribution to the field was the Computer Oracle and Password System, commonly known as COPS, which he developed in 1989 while at Purdue University. Gene Spafford, one of his professors, helped him initiate the project. COPS comprised several small, specialized vulnerability scanners designed to identify security weaknesses within individual components of a Unix operating system. The tool represented an early systematic approach to automated security auditing on Unix platforms.

SATAN and Controversy

In 1995, Farmer collaborated with Wietse Venema, a Dutch programmer and physicist, to develop the Security Administrator Tool for Analyzing Networks, widely known as SATAN. Upon its release, the tool generated significant controversy. Some network administrators and law enforcement personnel misunderstood its capabilities and feared it would enable hackers to identify and compromise vulnerable systems. As a result of this controversy, SGI terminated Farmer's employment.

Despite the alarm it caused, SATAN did not function as an automated attack tool. It operated as a network security audit utility, identifying vulnerabilities and offering suggestions to address them, without providing any information on how those vulnerabilities could be exploited. Within a few years, vulnerability scanners of this type became a widely accepted method for auditing computer and network security, and SATAN is recognized as an important milestone in that normalization.

Titan and Continued Research

Farmer co-developed another vulnerability scanner called Titan alongside Brad Powell and Matt Archibald. The three presented the tool at the Large Installation System Administration Conference, known as LISA, in 1998. Titan continued the tradition of providing system administrators with practical tools for assessing and hardening security configurations.

Computer Forensics

Farmer and Venema collaborated a second time to develop The Coroner's Toolkit, a suite of computer forensics tools. Building on that work, the two coauthored Forensic Discovery, a book on computer forensics published in 2005. These contributions helped establish foundational methodologies and tooling for the discipline of digital forensic investigation.

Industry and Entrepreneurship

Farmer co-founded Elemental Security alongside Dayne Myers and served as the company's chief technical officer. In this role, he continued to apply his expertise in security research to commercial security solutions.

Legacy

Farmer's career spans several defining moments in the history of computer security. From his early work on COPS at Purdue to the landmark release of SATAN and his contributions to computer forensics, he helped shape the tools and practices that underpin modern security auditing and incident response. His willingness to release powerful security tools publicly, despite controversy, contributed to a broader cultural and professional shift toward proactive, audit-based approaches to network defense.