Mika Ayenson, PhD
8993d1450b
--------- Co-authored-by: Ruben Groenewoud <78494512+Aegrah@users.noreply.github.com> Co-authored-by: Isai <59296946+imays11@users.noreply.github.com> Co-authored-by: terrancedejesus <terrance.dejesus@elastic.co> Co-authored-by: Jonhnathan <26856693+w0rk3r@users.noreply.github.com> Co-authored-by: eric-forte-elastic <eric.forte@elastic.co>
74 lines
2.0 KiB
TOML
74 lines
2.0 KiB
TOML
[metadata]
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creation_date = "2023/07/06"
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integration = ["endpoint"]
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maturity = "production"
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updated_date = "2026/03/24"
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[rule]
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author = ["Elastic"]
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building_block_type = "default"
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description = """
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Identifies the image load of a compression DLL. Adversaries will often compress and encrypt data in preparation for
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exfiltration.
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"""
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from = "now-119m"
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index = ["logs-endpoint.events.library-*"]
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interval = "60m"
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language = "eql"
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license = "Elastic License v2"
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name = "Compression DLL Loaded by Unusual Process"
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risk_score = 21
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rule_id = "d197478e-39f0-4347-a22f-ba654718b148"
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severity = "low"
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tags = [
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"Domain: Endpoint",
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"OS: Windows",
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"Use Case: Threat Detection",
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"Tactic: Collection",
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"Data Source: Elastic Defend",
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"Rule Type: BBR",
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]
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timestamp_override = "event.ingested"
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type = "eql"
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query = '''
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library where host.os.type == "windows" and event.action == "load" and
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dll.name : ("System.IO.Compression.FileSystem.ni.dll", "System.IO.Compression.ni.dll") and
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not
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(
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(
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process.executable : (
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"?:\\Program Files\\*",
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"?:\\Program Files (x86)\\*",
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"?:\\Windows\\Microsoft.NET\\Framework*\\mscorsvw.exe",
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"?:\\Windows\\System32\\sdiagnhost.exe",
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"?:\\Windows\\System32\\inetsrv\\w3wp.exe",
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"?:\\Windows\\SysWOW64\\inetsrv\\w3wp.exe",
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"?:\\ProgramData\\Microsoft\\Windows Defender Advanced Threat Protection\\DataCollection\\*\\OpenHandleCollector.exe"
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) and process.code_signature.trusted == true
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) or
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(
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process.name : "NuGet.exe" and process.code_signature.trusted == true and user.id : ("S-1-5-18", "S-1-5-20")
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)
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)
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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 = "T1560"
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name = "Archive Collected Data"
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reference = "https://attack.mitre.org/techniques/T1560/"
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[[rule.threat.technique.subtechnique]]
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id = "T1560.002"
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name = "Archive via Library"
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reference = "https://attack.mitre.org/techniques/T1560/002/"
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[rule.threat.tactic]
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id = "TA0009"
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name = "Collection"
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reference = "https://attack.mitre.org/tactics/TA0009/"
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