Service Account Security

Service Account Security

Service accounts present unique security challenges due to their non-interactive nature and typically elevated privileges. These accounts often have passwords that never expire and access to sensitive resources, making them attractive targets for attackers. Proper service account management requires different approaches than standard user accounts while maintaining strict security controls.

Windows service account security has evolved with Managed Service Accounts (MSAs) and Group Managed Service Accounts (gMSAs). These account types provide automatic password management, eliminating the need for manual password changes. Create gMSAs using PowerShell: New-ADServiceAccount -Name "svc_webapp" -DNSHostName "webapp.domain.com" -PrincipalsAllowedToRetrieveManagedPassword "WebServers". gMSAs support multiple computers, making them ideal for services running on multiple servers.

Linux service accounts require careful configuration to balance security with functionality. Create service accounts with disabled passwords and restricted shells: useradd -r -s /sbin/nologin -d /var/lib/servicename servicename. Use sudo rules for any interactive access needed for troubleshooting. Implement SSH key-based authentication for service accounts requiring remote access, restricting keys with command limitations: command="/usr/local/bin/backup.sh" ssh-rsa AAAAB3...

Service account passwords, when required, need special handling. Use password vaulting solutions storing passwords securely and providing programmatic access. Rotate service account passwords regularly through automated processes, updating all dependent services simultaneously. Monitor service account usage for anomalies, as attackers often target these accounts for persistence. Implement separation of duties where service account password changes require multiple approvals.