From e170935f1fef3350c76d8a4099e46f1ed44effa2 Mon Sep 17 00:00:00 2001
From: Austin Songer <austin@songer.pro>
Date: Thu, 12 Aug 2021 14:36:50 -0500
Subject: [PATCH] [New Rule] AWS EC2 Security Group Configuration Change
 Detection (#1144)

(cherry picked from commit 67ba66c8e7ebfc93a9922349740d899c80a59ac6)
---
 ..._group_configuration_change_detection.toml | 57 +++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 rules/aws/persistence_ec2_security_group_configuration_change_detection.toml

diff --git a/rules/aws/persistence_ec2_security_group_configuration_change_detection.toml b/rules/aws/persistence_ec2_security_group_configuration_change_detection.toml
new file mode 100644
index 000000000..da0f4d780
--- /dev/null
+++ b/rules/aws/persistence_ec2_security_group_configuration_change_detection.toml
@@ -0,0 +1,57 @@
+[metadata]
+creation_date = "2021/05/05"
+maturity = "production"
+updated_date = "2021/05/05"
+
+[rule]
+author = ["Elastic", "Austin Songer"]
+description = """
+Identifies a change to an AWS Security Group Configuration. A security group is like a virtul firewall and modifying
+configurations may allow unauthorized access. Threat actors may abuse this to establish persistence, exfiltrate data, or
+pivot in a AWS environment.
+"""
+false_positives = [
+    """
+    A security group may be created by a system or network administrator. Verify whether the user identity, user
+    agent, and/or hostname should be making changes in your environment. Security group creations from unfamiliar users
+    or hosts should be investigated. If known behavior is causing false positives, it can be exempted from the rule.
+    """,
+]
+from = "now-30m"
+index = ["filebeat-*", "logs-aws*"]
+interval = "10m"
+language = "kuery"
+license = "Elastic License v2"
+name = "AWS Security Group Configuration Change Detection"
+note = """## Config
+
+The AWS Fleet integration, Filebeat module, or similarly structured data is required to be compatible with this rule."""
+references = ["https://docs.aws.amazon.com/AWSEC2/latest/WindowsGuide/ec2-security-groups.html"]
+risk_score = 21
+rule_id = "29052c19-ff3e-42fd-8363-7be14d7c5469"
+severity = "low"
+tags = ["Elastic", "Cloud", "AWS", "Continuous Monitoring", "SecOps", "Network Security"]
+timestamp_override = "event.ingested"
+type = "query"
+
+query = '''
+event.dataset:aws.cloudtrail and event.provider:iam.amazonaws.com and event.action:(AuthorizeSecurityGroupEgress or 
+CreateSecurityGroup or ModifyInstanceAttribute or ModifySecurityGroupRules or RevokeSecurityGroupEgress or 
+RevokeSecurityGroupIngress) and event.outcome:success
+'''
+
+
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+
+[rule.threat.tactic]
+name = "Persistence"
+id = "TA0003"
+reference = "https://attack.mitre.org/tactics/TA0003/"
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+
+[rule.threat.tactic]
+name = "Defense Evasion"
+id = "TA0005"
+reference = "https://attack.mitre.org/tactics/TA0005/"