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>
108 lines
4.9 KiB
TOML
108 lines
4.9 KiB
TOML
[metadata]
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creation_date = "2020/02/18"
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maturity = "production"
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updated_date = "2022/07/05"
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min_stack_comments = "Comprehensive timeline templates only available in 8.2+"
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min_stack_version = "8.2"
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[rule]
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author = ["Elastic"]
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description = "Identifies a suspicious parent child process relationship with cmd.exe descending from svchost.exe"
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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 = "Svchost spawning Cmd"
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note = """## Triage and analysis
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### Investigating Svchost spawning Cmd
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The Service Host process (SvcHost) is a system process that can host one, or multiple, Windows services in the Windows
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NT family of operating systems. Note that `Svchost.exe` is reserved for use by the operating system and should not be
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used by non-Windows services.
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This rule looks for the creation of the `cmd.exe` process with `svchost.exe` as its parent process. This is an unusual
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behavior that can indicate the masquerading of a malicious process as `svchost.exe` or exploitation for privilege
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escalation.
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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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- Investigate other alerts associated with the user/host during the past 48 hours.
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- Investigate abnormal behaviors observed by the subject process such as network connections, registry or file
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modifications, and any spawned child processes.
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- Retrieve the process executable and determine if it is malicious:
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- Use a private sandboxed malware analysis system to perform analysis.
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- Observe and collect information about the following activities:
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- Attempts to contact external domains and addresses.
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- File and registry access, modification, and creation activities.
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- Service creation and launch activities.
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- Scheduled tasks creation.
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- Use the PowerShell Get-FileHash cmdlet to get the files' SHA-256 hash values.
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- Search for the existence and reputation of the hashes in resources like VirusTotal, Hybrid-Analysis, CISCO Talos, Any.run, etc.
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### False positive analysis
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- This activity is unlikely to happen legitimately. Benign true positives (B-TPs) can be added as exceptions if necessary.
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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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- If the triage identified malware, search the environment for additional compromised hosts.
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- Implement temporary network rules, procedures, and segmentation to contain the malware.
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- Stop suspicious processes.
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- Immediately block the identified indicators of compromise (IoCs).
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- Inspect the affected systems for additional malware backdoors like reverse shells, reverse proxies, or droppers that
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attackers could use to reinfect the system.
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- Remove and block malicious artifacts identified during triage.
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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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references = [
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"https://nasbench.medium.com/demystifying-the-svchost-exe-process-and-its-command-line-options-508e9114e747"
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]
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risk_score = 21
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rule_id = "fd7a6052-58fa-4397-93c3-4795249ccfa2"
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severity = "low"
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tags = ["Elastic", "Host", "Windows", "Threat Detection", "Execution"]
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timeline_id = "e70679c2-6cde-4510-9764-4823df18f7db"
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timeline_title = "Comprehensive Process Timeline"
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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 == "start" and
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process.parent.name : "svchost.exe" and process.name : "cmd.exe" and
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not (process.pe.original_file_name : "cmd.exe" and process.args : (
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"??:\\Program Files\\Npcap\\CheckStatus.bat?",
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"?:\\Program Files\\Npcap\\CheckStatus.bat",
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"\\system32\\cleanmgr.exe",
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"?:\\Windows\\system32\\silcollector.cmd",
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"\\system32\\AppHostRegistrationVerifier.exe",
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"\\system32\\ServerManagerLauncher.exe"))
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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 = "T1059"
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name = "Command and Scripting Interpreter"
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reference = "https://attack.mitre.org/techniques/T1059/"
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[rule.threat.tactic]
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id = "TA0002"
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name = "Execution"
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reference = "https://attack.mitre.org/tactics/TA0002/"
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