From 2e6b353f5e4cf72a3594d3f41e5a969c3ec146d6 Mon Sep 17 00:00:00 2001
From: Samirbous <64742097+Samirbous@users.noreply.github.com>
Date: Mon, 8 Feb 2021 22:57:55 +0100
Subject: [PATCH] [New Rule] Potential Reverse Shell Activity via Terminal
 (#821)

* [New Rule] Potential Reverse Shell Activity via Terminal

* extra reference

* adjusted process.args for coverage resilience

* Update execution_revershell_via_shell_cmd.toml

* Update rules/cross-platform/execution_revershell_via_shell_cmd.toml

Co-authored-by: Brent Murphy <56412096+bm11100@users.noreply.github.com>

* Update rules/cross-platform/execution_revershell_via_shell_cmd.toml

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

* encoded ref url

Co-authored-by: Brent Murphy <56412096+bm11100@users.noreply.github.com>
Co-authored-by: Justin Ibarra <brokensound77@users.noreply.github.com>
---
 .../execution_revershell_via_shell_cmd.toml   | 43 +++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 rules/cross-platform/execution_revershell_via_shell_cmd.toml

diff --git a/rules/cross-platform/execution_revershell_via_shell_cmd.toml b/rules/cross-platform/execution_revershell_via_shell_cmd.toml
new file mode 100644
index 000000000..71160cc8b
--- /dev/null
+++ b/rules/cross-platform/execution_revershell_via_shell_cmd.toml
@@ -0,0 +1,43 @@
+[metadata]
+creation_date = "2020/01/07"
+maturity = "production"
+updated_date = "2020/01/07"
+
+[rule]
+author = ["Elastic"]
+description = "Identifies the execution of a shell process with suspicious arguments which may be indicative of reverse shell activity."
+from = "now-9m"
+index = ["auditbeat-*", "logs-endpoint.events.*"]
+language = "eql"
+license = "Elastic License"
+name = "Potential Reverse Shell Activity via Terminal"
+references = [
+    "https://github.com/swisskyrepo/PayloadsAllTheThings/blob/master/Methodology%20and%20Resources/Reverse%20Shell%20Cheatsheet.md",
+    "https://github.com/WangYihang/Reverse-Shell-Manager",
+    "https://www.netsparker.com/blog/web-security/understanding-reverse-shells/",
+]
+risk_score = 73
+rule_id = "a1a0375f-22c2-48c0-81a4-7c2d11cc6856"
+severity = "high"
+tags = ["Elastic", "Host", "Linux", "macOS", "Threat Detection", "Execution"]
+type = "eql"
+
+query = '''
+process where event.type in ("start", "process_started") and
+  process.name in ("sh", "bash", "zsh", "dash", "zmodload") and
+  process.args:("*/dev/tcp/*", "*/dev/udp/*", "zsh/net/tcp", "zsh/net/udp")
+'''
+
+
+[[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.tactic]
+id = "TA0002"
+name = "Execution"
+reference = "https://attack.mitre.org/tactics/TA0002/"