Add: sigma rules (#175)

rules/sigma/windows/process_creation/win_net_enum.yml

@@ -0,0 +1,37 @@
+
+title: Windows Network Enumeration
+author: Endgame, JHasenbusch (ported for oscd.community)
+date: 2018/10/30
+description: Identifies attempts to enumerate hosts in a network using the built-in
+  Windows net.exe tool.
+detection:
+  SELECTION_1:
+    EventID: 1
+  SELECTION_2:
+    Image:
+    - '*\net.exe'
+    - '*\net1.exe'
+  SELECTION_3:
+    CommandLine: '*view*'
+  SELECTION_4:
+    CommandLine: '*\\\\*'
+  condition: (SELECTION_1 and (SELECTION_2 and SELECTION_3) and  not (SELECTION_4))
+falsepositives:
+- Legitimate use of net.exe utility by legitimate user
+fields:
+- ComputerName
+- User
+- CommandLine
+id: 62510e69-616b-4078-b371-847da438cc03
+level: low
+logsource:
+  category: process_creation
+  product: windows
+modified: 2019/11/11
+references:
+- https://eqllib.readthedocs.io/en/latest/analytics/b8a94d2f-dc75-4630-9d73-1edc6bd26fff.html
+- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1018/T1018.md
+status: stable
+tags:
+- attack.discovery
+- attack.t1018