sigma-rules/rules/ml/ml_high_count_network_denies.toml

[metadata]
creation_date = "2021/04/05"
maturity = "production"
updated_date = "2021/06/15"

[rule]
anomaly_threshold = 75
author = ["Elastic"]
description = """
A machine learning job detected an unusually large spike in network traffic that was 
denied by network access control lists (ACLs) or firewall rules. Such a burst of denied traffic is usually caused by
either 1) a mis-configured application or firewall or 2) suspicious or malicious activity. 
Unsuccessful attempts at network transit, in order to connect to command-and-control (C2), 
or engage in data exfiltration, may produce a burst of failed connections. This could also 
be due to unusually large amounts of reconnaissance or enumeration traffic. Denial-of-service 
attacks or traffic floods may also produce such a surge in traffic.
"""
false_positives = [
    """
    A misconfgured network application or firewall may trigger this alert. Security scans or test cycles may trigger this alert.
    """,
]
from = "now-30m"
interval = "15m"
license = "Elastic License v2"
machine_learning_job_id = "high_count_network_denies"
name = "Spike in Firewall Denies"
references = ["https://www.elastic.co/guide/en/security/current/prebuilt-ml-jobs.html"]
risk_score = 21
rule_id = "eaa77d63-9679-4ce3-be25-3ba8b795e5fa"
severity = "low"
tags = ["Elastic", "Network", "Threat Detection", "ML"]
type = "machine_learning"