From 14ef24e9ddfe86bc2080847bf5a5a712e9863033 Mon Sep 17 00:00:00 2001
From: Samirbous <64742097+Samirbous@users.noreply.github.com>
Date: Mon, 30 Nov 2020 21:02:57 +0100
Subject: [PATCH] [New Rule] Command shell activity started via rundll32 (#391)

* [New Rule] Command shell activity started via rundll32

* added tag

* adjusted parent args for performance

avoid leading wildcard

* filtered a common FP

* Update execution_command_shell_via_rundll32.toml

* Update rules/windows/execution_command_shell_via_rundll32.toml

Co-authored-by: David French <56409778+threat-punter@users.noreply.github.com>

* Update rules/windows/execution_command_shell_via_rundll32.toml

Co-authored-by: David French <56409778+threat-punter@users.noreply.github.com>

* Update rules/windows/execution_command_shell_via_rundll32.toml

Co-authored-by: David French <56409778+threat-punter@users.noreply.github.com>

* Update rules/windows/execution_command_shell_via_rundll32.toml

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

* Update rules/windows/execution_command_shell_via_rundll32.toml

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

Co-authored-by: David French <56409778+threat-punter@users.noreply.github.com>
Co-authored-by: Ross Wolf <31489089+rw-access@users.noreply.github.com>
Co-authored-by: Brent Murphy <56412096+bm11100@users.noreply.github.com>
Co-authored-by: Justin Ibarra <brokensound77@users.noreply.github.com>
---
 .../execution_command_shell_via_rundll32.toml | 53 +++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 rules/windows/execution_command_shell_via_rundll32.toml

diff --git a/rules/windows/execution_command_shell_via_rundll32.toml b/rules/windows/execution_command_shell_via_rundll32.toml
new file mode 100644
index 000000000..2e246c214
--- /dev/null
+++ b/rules/windows/execution_command_shell_via_rundll32.toml
@@ -0,0 +1,53 @@
+[metadata]
+creation_date = "2020/10/19"
+ecs_version = ["1.6.0"]
+maturity = "production"
+updated_date = "2020/10/19"
+
+[rule]
+author = ["Elastic"]
+description = "Identifies command shell activity started via RunDLL32, which is commonly abused by attackers to host malicious code."
+from = "now-9m"
+index = ["winlogbeat-*", "logs-endpoint.events.*"]
+language = "eql"
+license = "Elastic License"
+name = "Command Shell Activity Started via RunDLL32"
+risk_score = 21
+rule_id = "9ccf3ce0-0057-440a-91f5-870c6ad39093"
+severity = "low"
+tags = ["Elastic", "Host", "Windows", "Threat Detection", "Execution"]
+type = "eql"
+
+query = '''
+process where event.type in ("start", "process_started") and
+ process.name : ("cmd.exe", "powershell.exe") and
+  process.parent.name : "rundll32.exe" and 
+  /* common FPs can be added here */
+  not process.parent.args : "C:\\Windows\\System32\\SHELL32.dll,RunAsNewUser_RunDLL"
+'''
+
+
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+[[rule.threat.technique]]
+id = "T1059"
+name = "Command and Scripting Interpreter"
+reference = "https://attack.mitre.org/techniques/T1059/"
+
+
+[rule.threat.tactic]
+id = "TA0002"
+name = "Execution"
+reference = "https://attack.mitre.org/tactics/TA0002/"
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+[[rule.threat.technique]]
+id = "T1086"
+name = "PowerShell"
+reference = "https://attack.mitre.org/techniques/T1086/"
+
+
+[rule.threat.tactic]
+id = "TA0002"
+name = "Execution"
+reference = "https://attack.mitre.org/tactics/TA0002/"