From b49cce9fcbca54695f94fa75dc9fcc799f02e665 Mon Sep 17 00:00:00 2001
From: shashank-elastic <91139415+shashank-elastic@users.noreply.github.com>
Date: Thu, 10 Mar 2022 22:39:05 +0530
Subject: [PATCH] ssh shell evasion threat (#1827)

---
 rules/linux/defense_evasion_ssh_binary.toml | 50 +++++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100644 rules/linux/defense_evasion_ssh_binary.toml

diff --git a/rules/linux/defense_evasion_ssh_binary.toml b/rules/linux/defense_evasion_ssh_binary.toml
new file mode 100644
index 000000000..c5b5a55e7
--- /dev/null
+++ b/rules/linux/defense_evasion_ssh_binary.toml
@@ -0,0 +1,50 @@
+[metadata]
+creation_date = "2022/03/10"
+maturity = "production"
+updated_date = "2022/03/10"
+
+[rule]
+author = ["Elastic"]
+description = """
+Identifies Linux binary ssh abuse to break out from restricted environments by spawning an interactive system shell.This
+activity is not standard use with this binary for a user or system administrator and could potentially indicate
+malicious actor attempting to improve the capabilities or stability of their access.
+"""
+from = "now-9m"
+index = ["logs-endpoint.events.*"]
+language = "eql"
+license = "Elastic License v2"
+name = "Linux Restricted Shell Breakout via the ssh command"
+references = ["https://gtfobins.github.io/gtfobins/ssh/"]
+risk_score = 47
+rule_id = "97da359b-2b61-4a40-b2e4-8fc48cf7a294"
+severity = "medium"
+tags = ["Elastic", "Host", "Linux", "Threat Detection", "Defense Evasion", "GTFOBins"]
+timestamp_override = "event.ingested"
+type = "eql"
+
+query = '''
+sequence by host.id, process.pid with maxspan=1m
+[process where process.name == "ssh" and process.args == "-o" and process.args : ("ProxyCommand=;sh*", "ProxyCommand=;bash*", "ProxyCommand=;dash*", "ProxyCommand=;/bin/sh*", "ProxyCommand=;/bin/bash*", "ProxyCommand=;/bin/dash*")]
+[process where process.parent.name == "ssh" and process.name : ("bash", "sh", "dash")]
+'''
+
+
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+[[rule.threat.technique]]
+id = "T1548"
+name = "Abuse Elevation Control Mechanism"
+reference = "https://attack.mitre.org/techniques/T1548/"
+[[rule.threat.technique.subtechnique]]
+id = "T1548.004"
+name = "Elevated Execution with Prompt"
+reference = "https://attack.mitre.org/techniques/T1548/004/"
+
+
+
+[rule.threat.tactic]
+id = "TA0005"
+name = "Defense Evasion"
+reference = "https://attack.mitre.org/tactics/TA0005/"
+