This detection rule focuses on identifying the use of the 'base64' utility on macOS systems to decode base64-encoded text. The rule is triggered specifically when the 'base64' command is executed with the '-d' flag, which indicates decoding activity. The primary intent behind this detection strategy is to monitor for potentially malicious actions where attackers may obfuscate commands or data using base64 encoding as a means of evasion. The presence of such actions could suggest attempts to manipulate or execute hidden payloads. Given that the use of base64 can also occur during legitimate operations (hence the low severity level attributed to false positives), security teams should validate the context in which the command is executed. This rule provides foundational coverage against a common evasion technique associated with threat activities.