๐ง EXTERNAL VARIABLES
๐๏ธ Journeyman
๐ What You'll Learn Here
Passing dynamic values to YARA rules with `-d` โ environment awareness, user input, and reusable rules.
Learning Outline
- 1. Defining External Variables โ In-rule declaration with `extern` keyword
- 2. Passing Values โ `-d var=value` on command line
- 3. Data Types โ Integers, strings, booleans
- 4. Conditional Rules โ Environment-specific detection logic
- 5. Threshold Tuning โ Adjusting string counts, sizes dynamically
- 6. Whitelisting โ Passing whitelist paths as external vars
- 7. Batch Scanning โ Different values per scan in automation
- 8. API Integration โ Dynamic values from threat intelligence feeds
๐ ๏ธ VARIABLE MANAGER (Coming Soon)
Define and test external variable sets.
Define and test external variable sets.
๐ Resources
โ๏ธ Practice Challenge
Write a rule that matches only if `filesize` is less than the external variable `max_size`. Test with different values.