[New Rule] Web Server Suspicious User Agent Request Spike (#5340)

* [New Rule] Web Server Unusual User Agent Request

* [New Rule] Web Server Suspicious User Agent Request Spike

* Update reconnaissance_web_server_unusual_user_agents.toml

* Update reconnaissance_web_server_unusual_user_agents.toml

* ++

* ++

* Rename rule for suspicious user agent requests

* fixing from indices formatting

---------

Co-authored-by: Terrance DeJesus <99630311+terrancedejesus@users.noreply.github.com>
Co-authored-by: terrancedejesus <terrance.dejesus@elastic.co>
This commit is contained in:
Ruben Groenewoud
2025-11-24 19:30:22 +01:00
committed by GitHub
parent 4f8c967185
commit b0cc0cbe13
@@ -0,0 +1,133 @@
[metadata]
creation_date = "2025/11/19"
integration = ["nginx", "apache", "apache_tomcat", "iis", "network_traffic"]
maturity = "production"
updated_date = "2025/11/19"
[rule]
author = ["Elastic"]
description = """
This rule detects unusual spikes in web server requests with uncommon or suspicious user-agent strings. Such activity may
indicate reconnaissance attempts by attackers trying to identify vulnerabilities in web applications or servers. These
user-agents are often associated with automated tools used for scanning, vulnerability assessment, or brute-force attacks.
"""
from = "now-9m"
interval = "10m"
language = "esql"
license = "Elastic License v2"
name = "Web Server Suspicious User Agent Requests"
risk_score = 21
rule_id = "a1b7ffa4-bf80-4bf1-86ad-c3f4dc718b35"
severity = "low"
tags = [
"Domain: Web",
"Domain: Network",
"Use Case: Threat Detection",
"Tactic: Reconnaissance",
"Tactic: Credential Access",
"Data Source: Network Packet Capture",
"Data Source: Nginx",
"Data Source: Apache",
"Data Source: Apache Tomcat",
"Data Source: IIS",
]
timestamp_override = "event.ingested"
type = "esql"
query = '''
from logs-network_traffic.http-*, logs-network_traffic.tls-*, logs-nginx.access-*, logs-apache.access-*, logs-apache_tomcat.access-*, logs-iis.access-*
| eval Esql.user_agent_original_lower = to_lower(user_agent.original)
| where
(url.original is not null or url.full is not null) and
(
Esql.user_agent_original_lower like "mozilla/5.0 (windows nt 10.0; win64; x64) applewebkit/537.36 (khtml, like gecko) chrome/74.0.3729.169 safari/537.36" or // Nikto
Esql.user_agent_original_lower like "nikto*" or // Nikto
Esql.user_agent_original_lower like "mozilla/4.0 (compatible; msie 8.0; windows nt 5.1; trident/4.0)" or // Nessus Vulnerability Scanner
Esql.user_agent_original_lower like "*nessus*" or // Nessus Vulnerability Scanner
Esql.user_agent_original_lower like "sqlmap/*" or // SQLMap
Esql.user_agent_original_lower like "wpscan*" or // WPScan
Esql.user_agent_original_lower like "feroxbuster/*" or // Feroxbuster
Esql.user_agent_original_lower like "masscan*" or // Masscan & masscan-ng
Esql.user_agent_original_lower like "fuzz*" or // Ffuf
Esql.user_agent_original_lower like "mozilla/5.0 (windows nt 10.0; win64; x64) applewebkit/537.36 (khtml, like gecko) chrome/user_agent.original like~ 87.0.4280.88 safari/537.36" or // Dirsearch
Esql.user_agent_original_lower like "mozilla/4.0 (compatible; msie 6.0; windows nt 5.1)" or // Dirb
Esql.user_agent_original_lower like "dirbuster*" or // Dirbuster
Esql.user_agent_original_lower like "gobuster/*" or // Gobuster
Esql.user_agent_original_lower like "*dirsearch*" or // dirsearch
Esql.user_agent_original_lower like "*nmap*" or // Nmap Scripting Engine
Esql.user_agent_original_lower like "*hydra*" or // Hydra Brute Forcer
Esql.user_agent_original_lower like "*w3af*" or // w3af Web Application Attack and Audit Framework
Esql.user_agent_original_lower like "*arachni*" or // Arachni Web Application Security Scanner
Esql.user_agent_original_lower like "*skipfish*" or // Skipfish Web Application Security Scanner
Esql.user_agent_original_lower like "*openvas*" or // OpenVAS Vulnerability Scanner
Esql.user_agent_original_lower like "*acunetix*" or // Acunetix Vulnerability Scanner
Esql.user_agent_original_lower like "*zap*" or // OWASP ZAP
Esql.user_agent_original_lower like "*burp*" // Burp Suite
)
| eval Esql.url_text = case(url.original is not null, url.original, url.full)
| eval Esql.url_lower = to_lower(Esql.url_text)
| keep
@timestamp,
event.dataset,
user_agent.original,
source.ip,
agent.id,
host.name,
Esql.url_lower,
Esql.user_agent_original_lower
| stats
Esql.event_count = count(),
Esql.url_path_count_distinct = count_distinct(Esql.url_lower),
Esql.host_name_values = values(host.name),
Esql.agent_id_values = values(agent.id),
Esql.url_path_values = values(Esql.url_lower),
Esql.user_agent_original_values = values(Esql.user_agent_original_lower),
Esql.event_dataset_values = values(event.dataset)
by source.ip, agent.id
| where
Esql.event_count > 50 and Esql.url_path_count_distinct > 10
'''
[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1595"
name = "Active Scanning"
reference = "https://attack.mitre.org/techniques/T1595/"
[[rule.threat.technique.subtechnique]]
id = "T1595.001"
name = "Scanning IP Blocks"
reference = "https://attack.mitre.org/techniques/T1595/001/"
[[rule.threat.technique.subtechnique]]
id = "T1595.002"
name = "Vulnerability Scanning"
reference = "https://attack.mitre.org/techniques/T1595/002/"
[[rule.threat.technique.subtechnique]]
id = "T1595.003"
name = "Wordlist Scanning"
reference = "https://attack.mitre.org/techniques/T1595/003/"
[rule.threat.tactic]
id = "TA0043"
name = "Reconnaissance"
reference = "https://attack.mitre.org/tactics/TA0043/"
[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1110"
name = "Brute Force"
reference = "https://attack.mitre.org/techniques/T1110/"
[rule.threat.tactic]
id = "TA0006"
name = "Credential Access"
reference = "https://attack.mitre.org/tactics/TA0006/"