Mika Ayenson
a52751494e
* Convert config header to setup in note field * Parse note field into separate setup and note field with marko gfm * only validate and parse note on elastic authored rules and add CLI description for new DR_BYPASS_NOTE_VALIDATION_AND_PARSE environment variable Co-authored-by: brokensound77 <brokensound77@users.noreply.github.com>
96 lines
4.1 KiB
TOML
96 lines
4.1 KiB
TOML
[metadata]
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creation_date = "2020/02/18"
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maturity = "production"
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updated_date = "2022/05/09"
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[rule]
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author = ["Elastic"]
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description = """
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Windows services typically run as SYSTEM and can be used as a privilege escalation opportunity. Malware or penetration
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testers may run a shell as a service to gain SYSTEM permissions.
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"""
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from = "now-9m"
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index = ["winlogbeat-*", "logs-endpoint.events.*", "logs-windows.*"]
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language = "eql"
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license = "Elastic License v2"
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name = "System Shells via Services"
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note = """## Triage and analysis
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### Investigating System Shells via Services
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Attackers may configure existing services or create new ones to execute system shells to elevate their privileges from
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administrator to SYSTEM. They can also configure services to execute these shells with persistence payloads.
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This rule looks for system shells being spawned by `services.exe`, which is compatible with the above behavior.
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#### Possible investigation steps
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- Investigate the process execution chain (parent process tree) for unknown processes. Examine their executable files
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for prevalence, whether they are located in expected locations, and if they are signed with valid digital signatures.
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- Identify how the service was created or modified. Look for registry changes events or Windows events related to
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service activities (for example, 4697 and/or 7045).
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- Identify the user account that performed the action and whether it should perform this kind of action.
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- Contact the account owner and confirm whether they are aware of this activity.
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- Investigate other alerts associated with the user/host during the past 48 hours.
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- Assess whether this behavior is prevalent in the environment by looking for similar occurrences across hosts.
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- Check for commands executed under the spawned shell.
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### False positive analysis
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- This activity should not happen legitimately. The security team should address any potential benign true positive
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(B-TP), as this configuration can put the user and the domain at risk.
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### Response and remediation
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- Initiate the incident response process based on the outcome of the triage.
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- Isolate the involved host to prevent further post-compromise behavior.
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- Investigate credential exposure on systems compromised or used by the attacker to ensure all compromised accounts are
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identified. Reset passwords for these accounts and other potentially compromised credentials, such as email, business
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systems, and web services.
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- Delete the service or restore it to the original configuration.
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- Run a full antimalware scan. This may reveal additional artifacts left in the system, persistence mechanisms, and
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malware components.
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- Determine the initial vector abused by the attacker and take action to prevent reinfection through the same vector.
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- Using the incident response data, update logging and audit policies to improve the mean time to detect (MTTD) and the
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mean time to respond (MTTR).
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## Setup
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If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define `event.ingested` and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate `event.ingested` to @timestamp for this rule to work.
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"""
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risk_score = 47
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rule_id = "0022d47d-39c7-4f69-a232-4fe9dc7a3acd"
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severity = "medium"
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tags = ["Elastic", "Host", "Windows", "Threat Detection", "Persistence"]
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timestamp_override = "event.ingested"
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type = "eql"
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query = '''
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process where event.type in ("start", "process_started") and
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process.parent.name : "services.exe" and
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process.name : ("cmd.exe", "powershell.exe", "pwsh.exe", "powershell_ise.exe") and
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/* Third party FP's */
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not process.args : "NVDisplay.ContainerLocalSystem"
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'''
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[[rule.threat]]
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framework = "MITRE ATT&CK"
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[[rule.threat.technique]]
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id = "T1543"
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name = "Create or Modify System Process"
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reference = "https://attack.mitre.org/techniques/T1543/"
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[[rule.threat.technique.subtechnique]]
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id = "T1543.003"
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name = "Windows Service"
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reference = "https://attack.mitre.org/techniques/T1543/003/"
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[rule.threat.tactic]
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id = "TA0003"
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name = "Persistence"
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reference = "https://attack.mitre.org/tactics/TA0003/"
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