Suspicious Renaming of ESXI Files

 1[metadata]
 2creation_date = "2023/04/11"
 3integration = ["endpoint"]
 4maturity = "production"
 5min_stack_comments = "New fields added: required_fields, related_integrations, setup"
 6min_stack_version = "8.5.0"
 7updated_date = "2023/04/11"
 8
 9[rule]
10author = ["Elastic"]
11description = """
12Identifies instances where VMware-related files, such as those with extensions like ".vmdk", ".vmx", ".vmxf", ".vmsd",
13".vmsn", ".vswp", ".vmss", ".nvram", and ".vmem", are renamed on a Linux system. The rule monitors for the "rename"
14event action associated with these file types, which could indicate malicious activity.
15"""
16from = "now-9m"
17index = ["logs-endpoint.events.*"]
18language = "eql"
19license = "Elastic License v2"
20name = "Suspicious Renaming of ESXI Files"
21references = [
22    "https://www.bleepingcomputer.com/news/security/massive-esxiargs-ransomware-attack-targets-vmware-esxi-servers-worldwide/",
23]
24risk_score = 47
25rule_id = "97db8b42-69d8-4bf3-9fd4-c69a1d895d68"
26severity = "medium"
27tags = ["Elastic", "Host", "Linux", "Threat Detection", "Defense Evasion"]
28timestamp_override = "event.ingested"
29type = "eql"
30query = '''
31file where host.os.type == "linux" and event.action == "rename" and
32file.Ext.original.name : ("*.vmdk", "*.vmx", "*.vmxf", "*.vmsd", "*.vmsn", "*.vswp", "*.vmss", "*.nvram", "*.vmem")
33and not file.name : ("*.vmdk", "*.vmx", "*.vmxf", "*.vmsd", "*.vmsn", "*.vswp", "*.vmss", "*.nvram", "*.vmem")
34'''
35
36
37[[rule.threat]]
38framework = "MITRE ATT&CK"
39[[rule.threat.technique]]
40id = "T1036"
41name = "Masquerading"
42reference = "https://attack.mitre.org/techniques/T1036/"
43[[rule.threat.technique.subtechnique]]
44id = "T1036.003"
45name = "Rename System Utilities"
46reference = "https://attack.mitre.org/techniques/T1036/003/"
47
48
49
50[rule.threat.tactic]
51id = "TA0005"
52name = "Defense Evasion"
53reference = "https://attack.mitre.org/tactics/TA0005/"```