Ruben Groenewoud
100 lines
3.9 KiB
TOML
100 lines
3.9 KiB
TOML
[metadata]
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creation_date = "2024/03/06"
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integration = ["endpoint"]
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maturity = "production"
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updated_date = "2024/12/16"
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[rule]
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author = ["Elastic"]
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description = """
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This rule monitors for the creation or modification of Pluggable Authentication Module (PAM) shared object files or
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configuration files. Attackers may create or modify these files to maintain persistence on a compromised system, or
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harvest account credentials.
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"""
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false_positives = [
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"Trusted system module updates or allowed Pluggable Authentication Module (PAM) daemon configuration changes.",
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]
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from = "now-9m"
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index = ["logs-endpoint.events.file*"]
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language = "eql"
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license = "Elastic License v2"
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name = "Creation or Modification of Pluggable Authentication Module or Configuration"
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references = [
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"https://github.com/zephrax/linux-pam-backdoor",
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"https://github.com/eurialo/pambd",
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"http://0x90909090.blogspot.com/2016/06/creating-backdoor-in-pam-in-5-line-of.html",
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"https://www.trendmicro.com/en_us/research/19/i/skidmap-linux-malware-uses-rootkit-capabilities-to-hide-cryptocurrency-mining-payload.html",
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]
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risk_score = 47
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rule_id = "f48ecc44-7d02-437d-9562-b838d2c41987"
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severity = "medium"
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tags = [
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"Domain: Endpoint",
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"OS: Linux",
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"Use Case: Threat Detection",
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"Tactic: Credential Access",
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"Tactic: Persistence",
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"Data Source: Elastic Defend",
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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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file where host.os.type == "linux" and event.action in ("rename", "creation") and
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process.executable != null and (
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(file.path like~ (
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"/lib/security/*", "/lib64/security/*", "/usr/lib/security/*", "/usr/lib64/security/*",
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"/lib/x86_64-linux-gnu/security/*", "/usr/lib/x86_64-linux-gnu/security/*"
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) and file.extension == "so") or
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(file.path like~ "/etc/pam.d/*" and file.extension == null) or
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(file.path like~ "/etc/security/pam_*" or file.path == "/etc/pam.conf")
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) and not (
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process.executable in (
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"/bin/dpkg", "/usr/bin/dpkg", "/bin/dockerd", "/usr/bin/dockerd", "/usr/sbin/dockerd", "/bin/microdnf",
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"/usr/bin/microdnf", "/bin/rpm", "/usr/bin/rpm", "/bin/snapd", "/usr/bin/snapd", "/bin/yum", "/usr/bin/yum",
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"/bin/dnf", "/usr/bin/dnf", "/bin/podman", "/usr/bin/podman", "/bin/dnf-automatic", "/usr/bin/dnf-automatic",
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"/bin/pacman", "/usr/bin/pacman", "/usr/bin/dpkg-divert", "/bin/dpkg-divert", "/sbin/apk", "/usr/sbin/apk",
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"/usr/local/sbin/apk", "/usr/bin/apt", "/usr/sbin/pacman", "/bin/podman", "/usr/bin/podman", "/usr/bin/puppet",
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"/bin/puppet", "/opt/puppetlabs/puppet/bin/puppet", "/usr/bin/chef-client", "/bin/chef-client",
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"/bin/autossl_check", "/usr/bin/autossl_check", "/proc/self/exe", "/dev/fd/*", "/usr/bin/pamac-daemon",
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"/bin/pamac-daemon", "/usr/lib/snapd/snapd", "/usr/local/bin/dockerd", "/usr/sbin/pam-auth-update",
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"/usr/lib/systemd/systemd", "/usr/libexec/packagekitd", "/usr/bin/bsdtar", "/sbin/pam-auth-update"
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) or
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file.path like (
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"/tmp/snap.rootfs_*/pam_*.so", "/tmp/newroot/lib/*/pam_*.so", "/tmp/newroot/usr/lib64/security/pam_*.so"
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) or
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file.extension in ("swp", "swpx", "swx", "dpkg-remove") or
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file.Ext.original.extension == "dpkg-new" or
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process.executable like (
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"/nix/store/*", "/var/lib/dpkg/*", "/snap/*", "/dev/fd/*", "/usr/lib/virtualbox/*"
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) or
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(process.name == "sed" and file.name like~ "sed*") or
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(process.name == "perl" and file.name like~ "e2scrub_all.tmp*")
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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 = "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.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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[[rule.threat]]
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framework = "MITRE ATT&CK"
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[[rule.threat.technique]]
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id = "T1556"
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name = "Modify Authentication Process"
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reference = "https://attack.mitre.org/techniques/T1556/"
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[rule.threat.tactic]
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id = "TA0006"
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name = "Credential Access"
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reference = "https://attack.mitre.org/tactics/TA0006/"
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