Potential Shell via Wildcard Injection Detected

 1[metadata]
 2creation_date = "2023/07/28"
 3integration = ["endpoint"]
 4maturity = "production"
 5updated_date = "2024/07/18"
 6
 7[rule]
 8author = ["Elastic"]
 9description = """
10This rule monitors for the execution of a set of linux binaries, that are potentially vulnerable to wildcard injection,
11with suspicious command line flags followed by a shell spawn event. Linux wildcard injection is a type of security
12vulnerability where attackers manipulate commands or input containing wildcards (e.g., *, ?, []) to execute unintended
13operations or access sensitive data by tricking the system into interpreting the wildcard characters in unexpected ways.
14"""
15from = "now-9m"
16index = ["logs-endpoint.events.*"]
17language = "eql"
18license = "Elastic License v2"
19name = "Potential Shell via Wildcard Injection Detected"
20references = ["https://www.exploit-db.com/papers/33930"]
21risk_score = 47
22rule_id = "0b803267-74c5-444d-ae29-32b5db2d562a"
23setup = """## Setup
24
25This rule requires data coming in from Elastic Defend.
26
27### Elastic Defend Integration Setup
28Elastic Defend is integrated into the Elastic Agent using Fleet. Upon configuration, the integration allows the Elastic Agent to monitor events on your host and send data to the Elastic Security app.
29
30#### Prerequisite Requirements:
31- Fleet is required for Elastic Defend.
32- To configure Fleet Server refer to the [documentation](https://www.elastic.co/guide/en/fleet/current/fleet-server.html).
33
34#### The following steps should be executed in order to add the Elastic Defend integration on a Linux System:
35- Go to the Kibana home page and click "Add integrations".
36- In the query bar, search for "Elastic Defend" and select the integration to see more details about it.
37- Click "Add Elastic Defend".
38- Configure the integration name and optionally add a description.
39- Select the type of environment you want to protect, either "Traditional Endpoints" or "Cloud Workloads".
40- Select a configuration preset. Each preset comes with different default settings for Elastic Agent, you can further customize these later by configuring the Elastic Defend integration policy. [Helper guide](https://www.elastic.co/guide/en/security/current/configure-endpoint-integration-policy.html).
41- We suggest selecting "Complete EDR (Endpoint Detection and Response)" as a configuration setting, that provides "All events; all preventions"
42- Enter a name for the agent policy in "New agent policy name". If other agent policies already exist, you can click the "Existing hosts" tab and select an existing policy instead.
43For more details on Elastic Agent configuration settings, refer to the [helper guide](https://www.elastic.co/guide/en/fleet/8.10/agent-policy.html).
44- Click "Save and Continue".
45- To complete the integration, select "Add Elastic Agent to your hosts" and continue to the next section to install the Elastic Agent on your hosts.
46For more details on Elastic Defend refer to the [helper guide](https://www.elastic.co/guide/en/security/current/install-endpoint.html).
47"""
48severity = "medium"
49tags = [
50    "Domain: Endpoint",
51    "OS: Linux",
52    "Use Case: Threat Detection",
53    "Tactic: Privilege Escalation",
54    "Tactic: Execution",
55    "Data Source: Elastic Defend",
56]
57type = "eql"
58
59query = '''
60sequence by host.id with maxspan=1s
61  [process where host.os.type == "linux" and event.type == "start" and event.action == "exec" and (
62    (process.name == "tar" and process.args : "--checkpoint=*" and process.args : "--checkpoint-action=*") or
63    (process.name == "rsync" and process.args : "-e*") or
64    (process.name == "zip" and process.args == "--unzip-command")
65   ) and not process.executable : "/tmp/newroot/*"
66  ]  by process.entity_id
67  [process where host.os.type == "linux" and event.type == "start" and event.action == "exec" and 
68     process.parent.name : ("tar", "rsync", "zip") and 
69     process.name : ("bash", "dash", "sh", "tcsh", "csh", "zsh", "ksh", "fish")
70  ] by process.parent.entity_id
71'''
72
73[[rule.threat]]
74framework = "MITRE ATT&CK"
75
76[[rule.threat.technique]]
77id = "T1068"
78name = "Exploitation for Privilege Escalation"
79reference = "https://attack.mitre.org/techniques/T1068/"
80
81[rule.threat.tactic]
82id = "TA0004"
83name = "Privilege Escalation"
84reference = "https://attack.mitre.org/tactics/TA0004/"
85
86[[rule.threat]]
87framework = "MITRE ATT&CK"
88
89[[rule.threat.technique]]
90id = "T1059"
91name = "Command and Scripting Interpreter"
92reference = "https://attack.mitre.org/techniques/T1059/"
93
94[rule.threat.tactic]
95id = "TA0002"
96name = "Execution"
97reference = "https://attack.mitre.org/tactics/TA0002/"