nocase

Content matches are case-sensitive by default, but the nocase content modifier tells Snort to ignore case and look for the specified string match case-insensitively.

Format:

nocase

Examples:

content:"/index/vulnerable_endpoint.php",nocase;

# It is common to see nocase used with `fast_pattern` 
content:"super_secret_encryption_key",fast_pattern,nocase;

Note: The nocase option also applies to hex bytes; specifying content:"|41|",nocase; will look for either 'A' or 'a' in the packet.