The audit charter is the document that defines the purpose, authority and responsibility of the IS audit function. It provides IS audit professionals with the best source of direction for performing audit functions, as it establishes the scope, objectives, reporting lines, independence, accountability and resources of the IS audit function. The IT steering committee is a governance body that oversees the strategic alignment, prioritization and direction of IT initiatives, but it does not provide specific guidance for IS audit functions. The information security policy is a document that defines the rules and principles for protecting information assets in the organization, but it does not cover all aspects of IS audit functions. Audit best practices are general guidelines and recommendations for conducting effective and efficient audits, but they are not binding or authoritative sources of direction for IS audit functions. References: CISA Review Manual (Digital Version) 1, Chapter 1: Information Systems Auditing Process, Section 1.1: Audit Charter.

This should result in a finding because it violates the best practice of setting rules for groups rather than users. According to one of the web search results1, using group permissions instead of individual permissions can simplify the management and maintenance of ACLs, reduce the risk of human errors, and ensure consistency and compliance. Individual permissions can create conflicts, confusion, and security gaps in the ACLs. Therefore, the IS auditor should report this as a finding and recommend using group permissions instead.

It is acceptable for an IS auditor to rely on a third-party provider's external audit report on service level management when the scope and methodology meet audit requirements. This means that the external audit report covers the same objectives, criteria, standards and procedures that the IS auditor would use to assess the service level management. This way, the IS auditor can avoid duplication of work and reduce audit costs and efforts. The service provider's certification and accreditation, the report's confirmation of service levels and the report's release date are not sufficient to justify reliance on the external audit report. References: CISA Review Manual (Digital Version) , Chapter 2, Section 2.3.3.

The best method for maintaining the security of corporate applications pushed to employee-owned mobile devices is implementing mobile device management (MDM). MDM is a software solution that allows an organization to remotely manage, configure, and secure the mobile devices that access its network and data.
MDM can help protect corporate applications on employee-owned devices by:
* Enforcing security policies and settings, such as encryption, password, firewall, antivirus, and VPN.
* Controlling the installation, update, and removal of corporate applications and data.
* Separating corporate and personal data and applications on the device using containers or profiles.
* Monitoring and auditing the device's compliance status, activity, and location.
* Performing remote actions, such as lock, wipe, backup, or restore, in case of loss, theft, or compromise.
MDM can provide a comprehensive and centralized approach to maintain the security of corporate applications on employee-owned devices, regardless of the device type, platform, or ownership. MDM can also help the organization comply with regulatory and industry standards for data protection and privacy.
Enabling remote data destruction capabilities is a useful feature for maintaining the security of corporate applications on employee-owned devices, but it is not the best method by itself. Remote data destruction allows the organization to erase the corporate data and applications from the device in case of loss, theft, or compromise. However, this feature does not prevent unauthorized access or misuse of the corporate data and applications before they are destroyed. Remote data destruction is usually part of an MDM solution.
Disabling unnecessary network connectivity options is a good practice for maintaining the security of corporate applications on employee-owned devices, but it is not the best method by itself. Network connectivity options, such as Wi-Fi, Bluetooth, NFC, or USB, can expose the device to potential attacks or data leakage. Disabling these options when they are not needed can reduce the attack surface and improve battery life. However, this practice does not address other security risks or requirements for the corporate applications on the device. Disabling network connectivity options can also be part of an MDM solution.
Requiring security awareness training for mobile users is an important measure for maintaining the security of corporate applications on employee-owned devices, but it is not the best method by itself. Security awareness training can educate the users about the potential threats and best practices for using their devices securely. It can also help foster a culture of security and responsibility among the users. However, security awareness training cannot guarantee that the users will follow the security policies and guidelines consistently and correctly. Security awareness training should be complemented by technical controls, such as MDM.
References:
* Protecting Corporate Data on Mobile Devices for All Companies1
* Mobile Device Security: Corporate-Owned Personally-Enabled (COPE)23