From c4fea2fc00ff37b69ce218d190b4be4d7c3b0c00 Mon Sep 17 00:00:00 2001
From: shashank-elastic <91139415+shashank-elastic@users.noreply.github.com>
Date: Sat, 5 Mar 2022 01:16:19 +0530
Subject: [PATCH] [New Rule] Linux Restricted Shell Breakout via the Vi command
 (#1809)

* new:rule:issue-1808 vi shell evasion threat

* Update rules/linux/defense_evasion_vi_binary.toml

* Update rules/linux/defense_evasion_vi_binary.toml

Co-authored-by: Justin Ibarra <brokensound77@users.noreply.github.com>

* new:rule:issue-1808 vi shell evasion threat

* new:rule:issue-1808 vi shell evasion threat

* new:rule:issue-1808 vi shell evasion threat

* Update rules/linux/defense_evasion_vi_binary.toml

Co-authored-by: Colson Wilhoit <48036388+DefSecSentinel@users.noreply.github.com>
Co-authored-by: Justin Ibarra <brokensound77@users.noreply.github.com>

(cherry picked from commit 2a82f18e437f598651143aa6719162589eebd31f)
---
 rules/linux/defense_evasion_vi_binary.toml | 67 ++++++++++++++++++++++
 1 file changed, 67 insertions(+)
 create mode 100644 rules/linux/defense_evasion_vi_binary.toml

diff --git a/rules/linux/defense_evasion_vi_binary.toml b/rules/linux/defense_evasion_vi_binary.toml
new file mode 100644
index 000000000..2f3a714e1
--- /dev/null
+++ b/rules/linux/defense_evasion_vi_binary.toml
@@ -0,0 +1,67 @@
+[metadata]
+creation_date = "2022/03/03"
+maturity = "production"
+updated_date = "2022/03/03"
+
+[rule]
+author = ["Elastic"]
+description = """
+Identifies Linux binary find 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 vi command"
+references = ["https://gtfobins.github.io/gtfobins/vi/"]
+risk_score = 47
+rule_id = "89583d1b-3c2e-4606-8b74-0a9fd2248e88"
+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 == "vi" and process.args : "-c" and process.args : (":!/bin/bash", ":!/bin/sh", ":!bash", ":!sh")]
+[process where process.parent.name == "vi" and process.name : ("bash", "sh")]
+'''
+
+
+[[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/"
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+[[rule.threat.technique]]
+id = "T1059"
+name = "Command and Scripting Interpreter"
+reference = "https://attack.mitre.org/techniques/T1059/"
+[[rule.threat.technique.subtechnique]]
+id = "T1059.004"
+name = "Unix Shell"
+reference = "https://attack.mitre.org/techniques/T1059/004/"
+
+
+
+[rule.threat.tactic]
+id = "TA0002"
+name = "Execution"
+reference = "https://attack.mitre.org/tactics/TA0002/"
+