LoFP / system administrators may use looks like net.exe or \"dir commandline\" for troubleshooting or administrations tasks. however, this will typically come only from certain users and certain systems that can be added to an allow list.

Techniques

• T1135

Sample rules

Network Share Discovery Via Dir Command

• source: splunk
• technicques:
  • T1135

Description

The following analytic identifies object access on Windows administrative SMB shares (Admin$, IPC$, C$). This represents suspicious behavior as its commonly used by tools like PsExec/PaExec and others to stage service binaries before creating and starting a Windows service on remote endpoints. Red Teams and adversaries alike may abuse administrative shares for lateral movement and remote code execution. The IcedID malware family also implements this behavior to try to infect other machines in the infected network.

Detection logic

`wineventlog_security` EventCode=5140 ShareName IN("\\\\*\\ADMIN$","\\\\*\\C$","*\\\\*\\IPC$") AccessMask= 0x1 
| stats min(_time) as firstTime max(_time) as lastTime count by ShareName IpAddress ObjectType SubjectUserName SubjectDomainName IpPort AccessMask Computer 
| rename Computer as dest 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `network_share_discovery_via_dir_command_filter`