Accepted Default Telnet Port Connection

 1[metadata]
 2creation_date = "2020/02/18"
 3integration = ["network_traffic", "panw"]
 4maturity = "production"
 5updated_date = "2024/09/18"
 6
 7[rule]
 8author = ["Elastic"]
 9description = """
10This rule detects network events that may indicate the use of Telnet traffic. Telnet is commonly used by system
11administrators to remotely control older or embedded systems using the command line shell. It should almost never be
12directly exposed to the Internet, as it is frequently targeted and exploited by threat actors as an initial access or
13backdoor vector. As a plain-text protocol, it may also expose usernames and passwords to anyone capable of observing the
14traffic.
15"""
16false_positives = [
17    """
18    IoT (Internet of Things) devices and networks may use telnet and can be excluded if desired. Some business
19    work-flows may use Telnet for administration of older devices. These often have a predictable behavior. Telnet
20    activity involving an unusual source or destination may be more suspicious. Telnet activity involving a production
21    server that has no known associated Telnet work-flow or business requirement is often suspicious.
22    """,
23]
24from = "now-9m"
25index = ["packetbeat-*", "auditbeat-*", "filebeat-*", "logs-network_traffic.*", "logs-panw.panos*"]
26language = "kuery"
27license = "Elastic License v2"
28name = "Accepted Default Telnet Port Connection"
29risk_score = 47
30rule_id = "34fde489-94b0-4500-a76f-b8a157cf9269"
31severity = "medium"
32tags = [
33    "Domain: Endpoint",
34    "Use Case: Threat Detection",
35    "Tactic: Command and Control",
36    "Tactic: Lateral Movement",
37    "Tactic: Initial Access",
38    "Data Source: PAN-OS"
39]
40timeline_id = "300afc76-072d-4261-864d-4149714bf3f1"
41timeline_title = "Comprehensive Network Timeline"
42timestamp_override = "event.ingested"
43type = "query"
44
45query = '''
46(event.dataset:network_traffic.flow or event.category:(network or network_traffic))
47    and event.type:connection and not event.action:(
48        flow_dropped or flow_denied or denied or deny or
49        flow_terminated or timeout or Reject or network_flow)
50    and destination.port:23
51'''
52
53
54[[rule.threat]]
55framework = "MITRE ATT&CK"
56
57[rule.threat.tactic]
58id = "TA0011"
59name = "Command and Control"
60reference = "https://attack.mitre.org/tactics/TA0011/"
61[[rule.threat]]
62framework = "MITRE ATT&CK"
63[[rule.threat.technique]]
64id = "T1021"
65name = "Remote Services"
66reference = "https://attack.mitre.org/techniques/T1021/"
67
68
69[rule.threat.tactic]
70id = "TA0008"
71name = "Lateral Movement"
72reference = "https://attack.mitre.org/tactics/TA0008/"
73[[rule.threat]]
74framework = "MITRE ATT&CK"
75[[rule.threat.technique]]
76id = "T1190"
77name = "Exploit Public-Facing Application"
78reference = "https://attack.mitre.org/techniques/T1190/"
79
80
81[rule.threat.tactic]
82id = "TA0001"
83name = "Initial Access"
84reference = "https://attack.mitre.org/tactics/TA0001/"