Network Share Discovery
Networks often contain shared network drives and folders that enable users to access file directories on various systems across a network.
Net can be used to query a remote system for available shared drives using the
net view \remotesystem command. It can also be used to query shared drives on the local system using
Adversaries may look for folders and drives shared on remote systems as a means of identifying sources of information to gather as a precursor for Collection and to identify potential systems of interest for Lateral Movement.
On Mac, locally mounted shares can be viewed with the
df -aH command.
Cloud virtual networks may contain remote network shares or file storage services accessible to an adversary after they have obtained access to a system. For example, AWS, GCP, and Azure support creation of Network File System (NFS) shares and Server Message Block (SMB) shares that may be mapped on endpoint or cloud-based systems.
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
System and network discovery techniques normally occur throughout an operation as an adversary learns the environment. Data and events should not be viewed in isolation, but as part of a chain of behavior that could lead to other activities, such as Lateral Movement, based on the information obtained.
Normal, benign system and network events related to legitimate remote system discovery may be uncommon, depending on the environment and how they are used. Monitor processes and command-line arguments for actions that could be taken to gather system and network information. Remote access tools with built-in features may interact directly with the Windows API to gather information. Information may also be acquired through Windows system management tools such as Windows Management Instrumentation and PowerShell.
In cloud-based systems, native logging can be used to identify access to certain APIs and dashboards that may contain system information. Depending on how the environment is used, that data alone may not be sufficient due to benign use during normal operations.
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