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ANIMAL

Incident Summary

ANIMAL early trojan horse program replicates across mainframes

ANIMAL was one of the earliest documented examples of a self-replicating "trojan horse" program. Created by John Walker, it presented as a simple "20 questions" game guessing animals but secretly searched the system for other terminals and copies of itself. When run on a clean system, it would install a "Trojan Horse" version of itself in the user's account, gradually propagating throughout the system.

Date
1975-01-01 to 1976-01-01
Category
Open Source
Target Surface
Distribution
Insertion Phase
source
Impact
Benign
Cause
Sabotage

What Was Affected

Package ANIMAL
LanguageAssembly
ComponentGame
Artifact typesource archive
Domain typeproject download host
Domain fourmilab.ch

Compromised Versions

  • 1975 UNIVAC 1100 Series Version

Incident Context

Motive
Experimentation/Notoriety
Attribution
Author
Transitive
No
User Impact
25
Observed Duration
365 days

Evidence

Compromised Artifacts

Current Artifacts and Analysis

Indicators and Changes

Hashes

  • md5:45ad4d25c049b3dc75efc0a725bb8a4f

Commits

  • Original code had no version control system

Source Data

Source record: oss/animal/meta.yaml