From 0fe12d25286bb7b2641ea3a7e539f4968db2d31a Mon Sep 17 00:00:00 2001
From: Samirbous <64742097+Samirbous@users.noreply.github.com>
Date: Tue, 1 Dec 2020 00:00:40 +0100
Subject: [PATCH] [New Rule] Suspicious Explorer Child Process (#430)

* [New Rule] Suspicious Explorer Child Process

* Update execution_via_explorer_suspicious_child_parent_args.toml

* removed timeline_id

* fixed typo

* adjusted args for better performance

* Update rules/windows/execution_via_explorer_suspicious_child_parent_args.toml

Co-authored-by: Brent Murphy <56412096+bm11100@users.noreply.github.com>

* Update rules/windows/execution_via_explorer_suspicious_child_parent_args.toml

Co-authored-by: Justin Ibarra <brokensound77@users.noreply.github.com>

* relinted

* relinted

Co-authored-by: Brent Murphy <56412096+bm11100@users.noreply.github.com>
Co-authored-by: Justin Ibarra <brokensound77@users.noreply.github.com>
---
 ...explorer_suspicious_child_parent_args.toml | 54 +++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 rules/windows/execution_via_explorer_suspicious_child_parent_args.toml

diff --git a/rules/windows/execution_via_explorer_suspicious_child_parent_args.toml b/rules/windows/execution_via_explorer_suspicious_child_parent_args.toml
new file mode 100644
index 000000000..a1d800274
--- /dev/null
+++ b/rules/windows/execution_via_explorer_suspicious_child_parent_args.toml
@@ -0,0 +1,54 @@
+[metadata]
+creation_date = "2020/10/29"
+ecs_version = ["1.6.0"]
+maturity = "production"
+updated_date = "2020/10/29"
+
+[rule]
+author = ["Elastic"]
+description = """
+Identifies a suspicious Windows explorer child process. Explorer.exe can be abused to launch malicious scripts or
+executables from a trusted parent process.
+"""
+from = "now-9m"
+index = ["logs-endpoint.events.*", "winlogbeat-*"]
+language = "eql"
+license = "Elastic License"
+name = "Suspicious Explorer Child Process"
+risk_score = 43
+rule_id = "9a5b4e31-6cde-4295-9ff7-6be1b8567e1b"
+severity = "medium"
+tags = ["Elastic", "Host", "Windows", "Threat Detection", "Execution"]
+type = "eql"
+
+query = '''
+process where event.type in ("start", "process_started") and
+  process.name : ("cscript.exe", "wscript.exe", "powershell.exe", "rundll32.exe", "cmd.exe", "mshta.exe", "regsvr32.exe") and
+  /* Explorer started via DCOM */
+  process.parent.name : "explorer.exe" and process.parent.args : "-Embedding"
+'''
+
+
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+[[rule.threat.technique]]
+id = "T1064"
+name = "Scripting"
+reference = "https://attack.mitre.org/techniques/T1064/"
+
+[[rule.threat.technique]]
+id = "T1192"
+name = "Spearphishing Link"
+reference = "https://attack.mitre.org/techniques/T1192/"
+
+[[rule.threat.technique]]
+id = "T1193"
+name = "Spearphishing Attachment"
+reference = "https://attack.mitre.org/techniques/T1193/"
+
+
+[rule.threat.tactic]
+id = "TA0002"
+name = "Execution"
+reference = "https://attack.mitre.org/tactics/TA0002/"
+