[metadata] creation_date = "2020/04/23" ecs_version = ["1.4.0"] maturity = "production" updated_date = "2020/04/23" [rule] author = ["Elastic"] description = """ Telnet provides a command line interface for communication with a remote device or server. This rule identifies Telnet network connections to publicly routable IP addresses. """ false_positives = [ """ Telnet can be used for both benign or malicious purposes. Telnet is included by default in some Linux distributions, so its presence is not inherently suspicious. The use of Telnet to manage devices remotely has declined in recent years in favor of more secure protocols such as SSH. Telnet usage by non-automated tools or frameworks may be suspicious. """, ] index = ["auditbeat-*"] language = "kuery" license = "Elastic License" name = "Connection to External Network via Telnet" risk_score = 47 rule_id = "e19e64ee-130e-4c07-961f-8a339f0b8362" severity = "medium" tags = ["Elastic", "Linux"] type = "query" query = ''' event.action:("connected-to" or "network_flow") and process.name:telnet and not destination.ip:(127.0.0.0/8 or 10.0.0.0/8 or 172.16.0.0/12 or 192.168.0.0/16 or "FE80::/10" or "::1/128") ''' [[rule.threat]] framework = "MITRE ATT&CK" [[rule.threat.technique]] id = "T1021" name = "Remote Services" reference = "https://attack.mitre.org/techniques/T1021/" [rule.threat.tactic] id = "TA0008" name = "Lateral Movement" reference = "https://attack.mitre.org/tactics/TA0008/"