Add: sigma rules (#175)

rules/sigma/windows/process_creation/win_apt_sofacy.yml

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+
+title: Sofacy Trojan Loader Activity
+author: Florian Roth, Jonhnathan Ribeiro, oscd.community
+date: 2018/03/01
+description: Detects Trojan loader acitivty as used by APT28
+detection:
+  SELECTION_1:
+    EventID: 1
+  SELECTION_2:
+    CommandLine: '*rundll32.exe*'
+  SELECTION_3:
+    CommandLine: '*%APPDATA%\\*'
+  SELECTION_4:
+    CommandLine: '*.dat",*'
+  SELECTION_5:
+    CommandLine: '*.dll",#1'
+  condition: (SELECTION_1 and (SELECTION_2 and SELECTION_3) and (SELECTION_4 or SELECTION_5))
+falsepositives:
+- Unknown
+id: ba778144-5e3d-40cf-8af9-e28fb1df1e20
+level: critical
+logsource:
+  category: process_creation
+  product: windows
+modified: 2020/11/28
+references:
+- https://researchcenter.paloaltonetworks.com/2018/02/unit42-sofacy-attacks-multiple-government-entities/
+- https://www.reverse.it/sample/e3399d4802f9e6d6d539e3ae57e7ea9a54610a7c4155a6541df8e94d67af086e?environmentId=100
+- https://twitter.com/ClearskySec/status/960924755355369472
+status: experimental
+tags:
+- attack.g0007
+- attack.execution
+- attack.t1059
+- attack.t1059.003
+- attack.defense_evasion
+- attack.t1085
+- car.2013-10-002
+- attack.t1218.011