Keychain
Where this stands
A reviewer read the telemetry and concluded there is nothing here to detect that a sibling technique does not already cover.
The single analytic AN1112 offers exactly one Sigma logsource, repeated across all three of its data components: {product: macos, service: unifiedlog}. That logsource has no field vocabulary to write against. Not in the brief, which gives only prose notes ('execution of security or osascript', 'access or unlock attempt to keychain database', 'read access to ~/Library/Keychains/login.keychain-db') and no field names anywhere. Not in lib/sigma, which contains no macOS mapping at all — scripts/mitre/logsource.mjs passes macOS channels straight through as {product: macos, service: } with the note 'macOS log', so nothing downstream knows what a field on that source is called. And not in Sigma's own taxonomy, where macOS process events are modelled as {category: process_creation, product: macos} with Image/CommandLine/ParentImage rather than as a unifiedlog service. […]
What the technique is
Adversaries may acquire credentials from Keychain. Keychain (or Keychain Services) is the macOS credential management system that stores account names, passwords, private keys, certificates, sensitive application data, payment data, and secure notes. There are three types of Keychains: Login Keychain, System Keychain, and Local Items (iCloud) Keychain. The default Keychain is the Login Keychain, which stores user passwords and information. The System Keychain stores items accessed by the operating system, such as items shared among users on a host. The Local Items (iCloud) Keychain is used for items synced with Apple’s iCloud service. Keychains can be viewed and edited through the Keychain Access application or using the command-line utility security. Keychain files are located in ~/Library/Keychains/, /Library/Keychains/, and /Network/Library/Keychains/. Adversaries may gather user credentials from Keychain storage/memory. For example, the command security dump-keychain –d will dump all Login Keychain credentials from ~/Library/Keychains/login.keychain-db. Adversaries may also directly read Login Keychain credentials from the ~/Library/Keychains/login.keychain file. Both methods require a password, where the default password for the Login Keychain is the current user’s password to login to the macOS host.
Read it on attack.mitre.orgWhat MITRE says you would watch
- AN1112
Detects suspicious access to macOS Keychain files and APIs. Observes processes invoking the 'security' utility or accessing Keychain databases directly, correlates these with abnormal parent process lineage or unexpected user context. Monitors attempts to dump, unlock, or read credential storage beyond normal application workflows.
Technique names and descriptions © MITRE ATT&CK®, CC BY 4.0. Not endorsed by MITRE.