From dc9c63d0432fe8d52017b769a49ef85a3d69b4bf Mon Sep 17 00:00:00 2001
From: Samirbous <64742097+Samirbous@users.noreply.github.com>
Date: Tue, 1 Dec 2020 20:30:03 +0100
Subject: [PATCH] [New Rule] Unusual Svchost ChildProc - ChildLess Services
 (#370)

* [New Rule] Unusual Svchost ChildProc - ChildLess Services

* changed tags

* changed rule filename

* Update rules/windows/privilege_escalation_unusual_svchost_childproc_childless.toml

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

* Update rules/windows/privilege_escalation_unusual_svchost_childproc_childless.toml

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

* Update rules/windows/privilege_escalation_unusual_svchost_childproc_childless.toml

Co-authored-by: dstepanic17 <57736958+dstepanic17@users.noreply.github.com>

* Update rules/windows/privilege_escalation_unusual_svchost_childproc_childless.toml

Co-authored-by: dstepanic17 <57736958+dstepanic17@users.noreply.github.com>

* Update rules/windows/privilege_escalation_unusual_svchost_childproc_childless.toml

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

Co-authored-by: Justin Ibarra <brokensound77@users.noreply.github.com>
Co-authored-by: dstepanic17 <57736958+dstepanic17@users.noreply.github.com>
Co-authored-by: Brent Murphy <56412096+bm11100@users.noreply.github.com>
---
 ...n_unusual_svchost_childproc_childless.toml | 67 +++++++++++++++++++
 1 file changed, 67 insertions(+)
 create mode 100644 rules/windows/privilege_escalation_unusual_svchost_childproc_childless.toml

diff --git a/rules/windows/privilege_escalation_unusual_svchost_childproc_childless.toml b/rules/windows/privilege_escalation_unusual_svchost_childproc_childless.toml
new file mode 100644
index 000000000..dd83c45f3
--- /dev/null
+++ b/rules/windows/privilege_escalation_unusual_svchost_childproc_childless.toml
@@ -0,0 +1,67 @@
+[metadata]
+creation_date = "2020/10/13"
+ecs_version = ["1.6.0"]
+maturity = "production"
+updated_date = "2020/10/13"
+
+[rule]
+author = ["Elastic"]
+description = """
+Identifies unusual child processes of Service Host (svchost.exe) that traditionally do not spawn any child processes. This may indicate
+a code injection or an equivalent form of exploitation.
+"""
+false_positives = ["Changes to Windows services or a rarely executed child process."]
+from = "now-9m"
+index = ["logs-endpoint.events.*", "winlogbeat-*"]
+language = "eql"
+license = "Elastic License"
+name = "Unusual Service Host Child Process - Childless Service"
+risk_score = 47
+rule_id = "6a8ab9cc-4023-4d17-b5df-1a3e16882ce7"
+severity = "medium"
+tags = ["Elastic", "Host", "Windows", "Threat Detection", "Defense Evasion"]
+type = "eql"
+
+query = '''
+process where event.type in ("start", "process_started") and
+     process.parent.name : "svchost.exe" and
+
+     /* based on svchost service arguments -s svcname where the service is known to be childless */
+
+    process.parent.args : ("WdiSystemHost","LicenseManager",
+      "StorSvc","CDPSvc","cdbhsvc","BthAvctpSvc","SstpSvc","WdiServiceHost",
+      "imgsvc","TrkWks","WpnService","IKEEXT","PolicyAgent","CryptSvc",
+      "netprofm","ProfSvc","StateRepository","camsvc","LanmanWorkstation",
+      "NlaSvc","EventLog","hidserv","DisplayEnhancementService","ShellHWDetection",
+      "AppHostSvc","fhsvc","CscService","PushToInstall") and
+
+      /* unknown FPs can be added here */
+
+     not process.name : ("WerFault.exe","WerFaultSecure.exe","wermgr.exe")
+'''
+
+
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+[[rule.threat.technique]]
+id = "T1093"
+name = "Process Hollowing"
+reference = "https://attack.mitre.org/techniques/T1093/"
+
+
+[rule.threat.tactic]
+id = "TA0004"
+name = "Privilege Escalation"
+reference = "https://attack.mitre.org/tactics/TA0004/"
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+[[rule.threat.technique]]
+id = "T1055"
+name = "Process Injection"
+reference = "https://attack.mitre.org/techniques/T1055/"
+
+
+[rule.threat.tactic]
+id = "TA0005"
+name = "Defense Evasion"
+reference = "https://attack.mitre.org/tactics/TA0005/"