Justin Ibarra
eeb8ab7744
* Expand timestamp_override tests
* removed timestamp_override from eql sequence rules
* add config entry for eql rules with beats index and t_o
* add timestamp_override to missing fields
Removed changes from:
- rules/cross-platform/impact_hosts_file_modified.toml
- rules/windows/credential_access_lsass_memdump_file_created.toml
- rules/windows/defense_evasion_adding_the_hidden_file_attribute_with_via_attribexe.toml
- rules/windows/defense_evasion_execution_lolbas_wuauclt.toml
- rules/windows/defense_evasion_suspicious_certutil_commands.toml
- rules/windows/execution_command_shell_started_by_svchost.toml
(selectively cherry picked from commit 6bdfddac8e)
58 lines
2.3 KiB
TOML
58 lines
2.3 KiB
TOML
[metadata]
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creation_date = "2020/07/16"
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maturity = "production"
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updated_date = "2022/03/31"
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[rule]
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author = ["Elastic"]
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description = """
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Identifies an unexpected file being modified by dns.exe, the process responsible for Windows DNS Server services, which
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may indicate activity related to remote code execution or other forms of exploitation.
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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 = "Unusual File Modification by dns.exe"
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note = """## Triage and analysis
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### Investigating Unusual File Write
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Detection alerts from this rule indicate potential unusual/abnormal file writes from the DNS Server service process (`dns.exe`) after exploitation from CVE-2020-1350 (SigRed) has occurred. Here are some possible avenues of investigation:
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- Post-exploitation, adversaries may write additional files or payloads to the system as additional discovery/exploitation/persistence mechanisms.
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- Any suspicious or abnormal files written from `dns.exe` should be reviewed and investigated with care.
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## Config
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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://research.checkpoint.com/2020/resolving-your-way-into-domain-admin-exploiting-a-17-year-old-bug-in-windows-dns-servers/",
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"https://msrc-blog.microsoft.com/2020/07/14/july-2020-security-update-cve-2020-1350-vulnerability-in-windows-domain-name-system-dns-server/",
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]
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risk_score = 73
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rule_id = "c7ce36c0-32ff-4f9a-bfc2-dcb242bf99f9"
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severity = "high"
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tags = ["Elastic", "Host", "Windows", "Threat Detection", "Initial Access"]
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timestamp_override = "event.ingested"
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type = "eql"
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query = '''
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file where process.name : "dns.exe" and event.type in ("creation", "deletion", "change") and
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not file.name : "dns.log"
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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 = "T1133"
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name = "External Remote Services"
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reference = "https://attack.mitre.org/techniques/T1133/"
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[rule.threat.tactic]
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id = "TA0001"
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name = "Initial Access"
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reference = "https://attack.mitre.org/tactics/TA0001/"
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