File Permission Modification in Writable Directory

 1[metadata]
 2creation_date = "2020/04/21"
 3integration = ["endpoint"]
 4maturity = "production"
 5min_stack_comments = "New fields added: required_fields, related_integrations, setup"
 6min_stack_version = "8.3.0"
 7updated_date = "2023/02/22"
 8
 9[rule]
10author = ["Elastic"]
11description = """
12Identifies file permission modifications in common writable directories by a non-root user. Adversaries often drop files
13or payloads into a writable directory and change permissions prior to execution.
14"""
15false_positives = [
16    """
17    Certain programs or applications may modify files or change ownership in writable directories. These can be exempted
18    by username.
19    """,
20]
21from = "now-9m"
22index = ["auditbeat-*", "logs-endpoint.events.*"]
23language = "kuery"
24license = "Elastic License v2"
25name = "File Permission Modification in Writable Directory"
26risk_score = 21
27rule_id = "9f9a2a82-93a8-4b1a-8778-1780895626d4"
28severity = "low"
29tags = ["Elastic", "Host", "Linux", "Threat Detection", "Defense Evasion"]
30timestamp_override = "event.ingested"
31type = "query"
32
33query = '''
34event.category:process and host.os.type:linux and event.type:(start or process_started) and
35  process.name:(chmod or chown or chattr or chgrp) and
36  process.working_directory:(/tmp or /var/tmp or /dev/shm) and
37  not user.name:root
38'''
39
40
41[[rule.threat]]
42framework = "MITRE ATT&CK"
43[[rule.threat.technique]]
44id = "T1222"
45name = "File and Directory Permissions Modification"
46reference = "https://attack.mitre.org/techniques/T1222/"
47
48
49[rule.threat.tactic]
50id = "TA0005"
51name = "Defense Evasion"
52reference = "https://attack.mitre.org/tactics/TA0005/"