Potential Command and Control via Internet Explorer

 1[metadata]
 2creation_date = "2020/11/28"
 3integration = ["endpoint"]
 4maturity = "production"
 5updated_date = "2024/05/21"
 6
 7[rule]
 8author = ["Elastic"]
 9description = """
10Identifies instances of Internet Explorer (iexplore.exe) being started via the Component Object Model (COM) making
11unusual network connections. Adversaries could abuse Internet Explorer via COM to avoid suspicious processes making
12network connections and bypass host-based firewall restrictions.
13"""
14false_positives = ["Processes such as MS Office using IEproxy to render HTML content."]
15from = "now-9m"
16index = ["logs-endpoint.events.library-*", "logs-endpoint.events.process-*", "logs-endpoint.events.network-*"]
17language = "eql"
18license = "Elastic License v2"
19name = "Potential Command and Control via Internet Explorer"
20risk_score = 47
21rule_id = "acd611f3-2b93-47b3-a0a3-7723bcc46f6d"
22severity = "medium"
23tags = [
24    "Domain: Endpoint",
25    "OS: Windows",
26    "Use Case: Threat Detection",
27    "Tactic: Command and Control",
28    "Data Source: Elastic Defend",
29]
30type = "eql"
31
32query = '''
33sequence by host.id, user.name with maxspan = 5s
34  [library where host.os.type == "windows" and dll.name : "IEProxy.dll" and process.name : ("rundll32.exe", "regsvr32.exe")]
35  [process where host.os.type == "windows" and event.type == "start" and process.parent.name : "iexplore.exe" and process.parent.args : "-Embedding"]
36  /* IE started via COM in normal conditions makes few connections, mainly to Microsoft and OCSP related domains, add FPs here */
37  [network where host.os.type == "windows" and network.protocol == "dns" and process.name : "iexplore.exe" and
38   not dns.question.name :
39   (
40    "*.microsoft.com",
41    "*.digicert.com",
42    "*.msocsp.com",
43    "*.windowsupdate.com",
44    "*.bing.com",
45    "*.identrust.com",
46    "*.sharepoint.com",
47    "*.office365.com",
48    "*.office.com"
49    )
50  ] /* with runs=5 */
51'''
52
53
54[[rule.threat]]
55framework = "MITRE ATT&CK"
56[[rule.threat.technique]]
57id = "T1071"
58name = "Application Layer Protocol"
59reference = "https://attack.mitre.org/techniques/T1071/"
60
61
62[rule.threat.tactic]
63id = "TA0011"
64name = "Command and Control"
65reference = "https://attack.mitre.org/tactics/TA0011/"
66[[rule.threat]]
67framework = "MITRE ATT&CK"
68[[rule.threat.technique]]
69id = "T1559"
70name = "Inter-Process Communication"
71reference = "https://attack.mitre.org/techniques/T1559/"
72[[rule.threat.technique.subtechnique]]
73id = "T1559.001"
74name = "Component Object Model"
75reference = "https://attack.mitre.org/techniques/T1559/001/"
76
77
78
79[rule.threat.tactic]
80id = "TA0002"
81name = "Execution"
82reference = "https://attack.mitre.org/tactics/TA0002/"