From 6bc4a6b9bb3cd306062cd8a276cb964533852b17 Mon Sep 17 00:00:00 2001
From: Samirbous <64742097+Samirbous@users.noreply.github.com>
Date: Tue, 8 Dec 2020 17:34:33 +0100
Subject: [PATCH] [New Rule] Linux System Log Files Deleted (#461)

* [New Rule] Linux System Log Files Deleted

* Update defense_evasion_log_files_deleted.toml

* Update rules/linux/defense_evasion_log_files_deleted.toml

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

* added linux to rule name as sug by JLB

* ecs_version

* Update rules/linux/defense_evasion_log_files_deleted.toml

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

* Update rules/linux/defense_evasion_log_files_deleted.toml

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

* Update rules/linux/defense_evasion_log_files_deleted.toml

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

* adjusted format

Co-authored-by: Justin Ibarra <brokensound77@users.noreply.github.com>
Co-authored-by: Brent Murphy <56412096+bm11100@users.noreply.github.com>
---
 .../defense_evasion_log_files_deleted.toml    | 54 +++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 rules/linux/defense_evasion_log_files_deleted.toml

diff --git a/rules/linux/defense_evasion_log_files_deleted.toml b/rules/linux/defense_evasion_log_files_deleted.toml
new file mode 100644
index 000000000..6584096a5
--- /dev/null
+++ b/rules/linux/defense_evasion_log_files_deleted.toml
@@ -0,0 +1,54 @@
+[metadata]
+creation_date = "2020/11/03"
+maturity = "production"
+updated_date = "2020/11/03"
+
+[rule]
+author = ["Elastic"]
+description = """
+Identifies the deletion of sensitive Linux system logs. This may indicate an attempt to evade detection or destroy forensic
+evidence on a system.
+"""
+from = "now-9m"
+index = ["auditbeat-*", "logs-endpoint.events.*"]
+language = "eql"
+license = "Elastic License"
+name = "System Log File Deletion"
+references = [
+    "https://www.fireeye.com/blog/threat-research/2020/11/live-off-the-land-an-overview-of-unc1945.html",
+]
+risk_score = 47
+rule_id = "aa895aea-b69c-4411-b110-8d7599634b30"
+severity = "medium"
+tags = ["Elastic", "Host", "Linux", "Threat Detection", "Defense Evasion"]
+type = "eql"
+
+query = '''
+file where event.type == "deletion" and 
+  file.path : 
+    (
+    "/var/run/utmp", 
+    "/var/log/wtmp", 
+    "/var/log/btmp", 
+    "/var/log/lastlog", 
+    "/var/log/faillog",
+    "/var/log/syslog", 
+    "/var/log/messages", 
+    "/var/log/secure", 
+    "/var/log/auth.log"
+    )
+'''
+
+
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+[[rule.threat.technique]]
+id = "T1070"
+name = "Indicator Removal on Host"
+reference = "https://attack.mitre.org/techniques/T1070/"
+
+
+[rule.threat.tactic]
+id = "TA0005"
+name = "Defense Evasion"
+reference = "https://attack.mitre.org/tactics/TA0005/"