[New Rule & Tuning] (Ana)Cron & At Job Creation (#3726)
* [New Rule & Tuning] (Ana)Cron & At Job Creation * Update persistence_at_job_creation.toml * Update persistence_cron_job_creation.toml * ++ * Incompatible endgame field * Update rules/linux/persistence_at_job_creation.toml Co-authored-by: Samirbous <64742097+Samirbous@users.noreply.github.com> * Update rules/linux/persistence_cron_job_creation.toml Co-authored-by: Samirbous <64742097+Samirbous@users.noreply.github.com> --------- Co-authored-by: Samirbous <64742097+Samirbous@users.noreply.github.com>
This commit is contained in:
Ruben Groenewoud
@@ -0,0 +1,133 @@
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[metadata]
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creation_date = "2024/05/31"
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integration = ["endpoint"]
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maturity = "production"
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updated_date = "2024/05/31"
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[rule]
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author = ["Elastic"]
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description = """
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This rule monitors for at jobs being created or renamed. Linux at jobs are scheduled tasks that can be leveraged by
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system administrators to set up scheduled tasks, but may be abused by malicious actors for persistence, privilege
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escalation and command execution. By creating or modifying cron job configurations, attackers can execute malicious
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commands or scripts at predefined intervals, ensuring their continued presence and enabling unauthorized activities.
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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 = "At Job Created or Modified"
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risk_score = 47
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rule_id = "84755a05-78c8-4430-8681-89cd6c857d71"
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setup = """## Setup
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This rule requires data coming in from Elastic Defend.
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### Elastic Defend Integration Setup
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Elastic Defend is integrated into the Elastic Agent using Fleet. Upon configuration, the integration allows the Elastic Agent to monitor events on your host and send data to the Elastic Security app.
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#### Prerequisite Requirements:
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- Fleet is required for Elastic Defend.
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- To configure Fleet Server refer to the [documentation](https://www.elastic.co/guide/en/fleet/current/fleet-server.html).
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#### The following steps should be executed in order to add the Elastic Defend integration on a Linux System:
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- Go to the Kibana home page and click "Add integrations".
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- In the query bar, search for "Elastic Defend" and select the integration to see more details about it.
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- Click "Add Elastic Defend".
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- Configure the integration name and optionally add a description.
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- Select the type of environment you want to protect, either "Traditional Endpoints" or "Cloud Workloads".
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- Select a configuration preset. Each preset comes with different default settings for Elastic Agent, you can further customize these later by configuring the Elastic Defend integration policy. [Helper guide](https://www.elastic.co/guide/en/security/current/configure-endpoint-integration-policy.html).
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- We suggest selecting "Complete EDR (Endpoint Detection and Response)" as a configuration setting, that provides "All events; all preventions"
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- Enter a name for the agent policy in "New agent policy name". If other agent policies already exist, you can click the "Existing hosts" tab and select an existing policy instead.
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For more details on Elastic Agent configuration settings, refer to the [helper guide](https://www.elastic.co/guide/en/fleet/8.10/agent-policy.html).
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- Click "Save and Continue".
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- To complete the integration, select "Add Elastic Agent to your hosts" and continue to the next section to install the Elastic Agent on your hosts.
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For more details on Elastic Defend refer to the [helper guide](https://www.elastic.co/guide/en/security/current/install-endpoint.html).
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"""
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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: Persistence",
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"Tactic: Privilege Escalation",
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"Tactic: Execution",
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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
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event.action in ("rename", "creation") and file.path : "/var/spool/cron/atjobs/*" 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/local/bin/dockerd"
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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 : ("/nix/store/*", "/var/lib/dpkg/*", "/tmp/vmis.*", "/snap/*", "/dev/fd/*") or
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process.executable == null or
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(process.name == "sed" and file.name : "sed*") or
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(process.name == "perl" and file.name : "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 = "T1053"
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name = "Scheduled Task/Job"
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reference = "https://attack.mitre.org/techniques/T1053/"
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[[rule.threat.technique.subtechnique]]
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id = "T1053.002"
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name = "At"
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reference = "https://attack.mitre.org/techniques/T1053/002/"
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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 = "T1053"
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name = "Scheduled Task/Job"
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reference = "https://attack.mitre.org/techniques/T1053/"
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[[rule.threat.technique.subtechnique]]
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id = "T1053.002"
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name = "At"
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reference = "https://attack.mitre.org/techniques/T1053/002/"
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[rule.threat.tactic]
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id = "TA0004"
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name = "Privilege Escalation"
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reference = "https://attack.mitre.org/tactics/TA0004/"
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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 = "T1053"
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name = "Scheduled Task/Job"
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reference = "https://attack.mitre.org/techniques/T1053/"
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[[rule.threat.technique.subtechnique]]
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id = "T1053.002"
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name = "At"
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reference = "https://attack.mitre.org/techniques/T1053/002/"
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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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@@ -2,24 +2,21 @@
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creation_date = "2023/06/09"
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integration = ["endpoint"]
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maturity = "production"
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min_stack_comments = "New fields added: required_fields, related_integrations, setup, New Term"
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min_stack_version = "8.6.0"
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updated_date = "2024/05/24"
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updated_date = "2024/05/31"
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[transform]
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[[transform.osquery]]
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label = "Osquery - Retrieve File Listing Information"
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query = """
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SELECT * FROM file WHERE ( path LIKE '/etc/cron.allow.d/%' OR path LIKE '/etc/cron.d/%' OR path LIKE
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SELECT * FROM file WHERE (path LIKE '/etc/cron.allow.d/%' OR path LIKE '/etc/cron.d/%' OR path LIKE
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'/etc/cron.hourly/%' OR path LIKE '/etc/cron.daily/%' OR path LIKE '/etc/cron.weekly/%' OR path LIKE
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'/etc/cron.monthly/%' )
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'/etc/cron.monthly/%' OR path LIKE '/var/spool/cron/crontabs/%')
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"""
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[[transform.osquery]]
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label = "Osquery - Retrieve rc-local.service File Information"
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label = "Osquery - Retrieve Cron File Information"
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query = """
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SELECT * FROM file WHERE ( path = '/etc/cron.allow' OR path = '/etc/cron.deny' OR path = '/etc/crontab' OR path =
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'/usr/sbin/cron' OR path = '/usr/sbin/anacron' )
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SELECT * FROM file WHERE (path = '/etc/cron.allow' OR path = '/etc/cron.deny' OR path = '/etc/crontab')
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"""
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[[transform.osquery]]
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@@ -30,7 +27,7 @@ file_last_access_time, datetime(f.mtime, 'unixepoch') AS file_last_modified_time
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file_last_status_change_time, datetime(f.btime, 'unixepoch') AS file_created_time, f.size AS size_bytes FROM file f LEFT
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JOIN users u ON f.uid = u.uid LEFT JOIN groups g ON f.gid = g.gid WHERE ( path LIKE '/etc/cron.allow.d/%' OR path LIKE
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'/etc/cron.d/%' OR path LIKE '/etc/cron.hourly/%' OR path LIKE '/etc/cron.daily/%' OR path LIKE '/etc/cron.weekly/%' OR
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path LIKE '/etc/cron.monthly/%' )
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path LIKE '/etc/cron.monthly/%' OR path LIKE '/var/spool/cron/crontabs/%')
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"""
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[[transform.osquery]]
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@@ -53,27 +50,28 @@ query = "SELECT * FROM users WHERE username = {{user.name}}"
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label = "Osquery - Investigate the Account Authentication Status"
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query = "SELECT * FROM logged_in_users WHERE user = {{user.name}}"
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[rule]
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author = ["Elastic"]
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description = """
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Linux cron jobs are scheduled tasks that can be leveraged by malicious actors for persistence, privilege escalation and
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command execution. By creating or modifying cron job configurations, attackers can execute malicious commands or scripts
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at predefined intervals, ensuring their continued presence and enabling unauthorized activities.
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This rule monitors for (ana)cron jobs being created or renamed. Linux cron jobs are scheduled tasks that can be
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leveraged by system administrators to set up scheduled tasks, but may be abused by malicious actors for persistence,
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privilege escalation and command execution. By creating or modifying cron job configurations, attackers can execute
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malicious commands or scripts at predefined intervals, ensuring their continued presence and enabling unauthorized
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activities.
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"""
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from = "now-9m"
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index = ["logs-endpoint.events.*", "endgame-*"]
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language = "kuery"
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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 = "Cron Job Created or Changed by Previously Unknown Process"
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name = "Cron Job Created or Modified"
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note = """## Triage and analysis
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### Investigating Cron Job Created or Changed by Previously Unknown Process
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### Investigating Cron Job Created or Modified
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Linux cron jobs are scheduled tasks that run at specified intervals or times, managed by the cron daemon.
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By creating or modifying cron job configurations, attackers can execute malicious commands or scripts at predefined intervals, ensuring their continued presence and enabling unauthorized activities.
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This rule monitors the creation of previously unknown cron jobs by monitoring for file creation events in the most common cron job task location directories.
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This rule monitors the creation of cron jobs by monitoring for file creation and rename events in the most common cron job task location directories.
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> **Note**:
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> This investigation guide uses the [Osquery Markdown Plugin](https://www.elastic.co/guide/en/security/master/invest-guide-run-osquery.html) introduced in Elastic Stack version 8.5.0. Older Elastic Stack versions will display unrendered Markdown in this guide.
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@@ -118,8 +116,8 @@ This rule monitors the creation of previously unknown cron jobs by monitoring fo
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- Suspicious File Creation in /etc for Persistence - 1c84dd64-7e6c-4bad-ac73-a5014ee37042
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- Potential Persistence Through Run Control Detected - 0f4d35e4-925e-4959-ab24-911be207ee6f
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- Potential Persistence Through init.d Detected - 474fd20e-14cc-49c5-8160-d9ab4ba16c8b
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- New Systemd Timer Created - 7fb500fa-8e24-4bd1-9480-2a819352602c
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- New Systemd Service Created by Previously Unknown Process - 17b0a495-4d9f-414c-8ad0-92f018b8e001
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- Systemd Timer Created - 7fb500fa-8e24-4bd1-9480-2a819352602c
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- Systemd Service Created - 17b0a495-4d9f-414c-8ad0-92f018b8e001
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### Response and remediation
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@@ -174,27 +172,33 @@ tags = [
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"Tactic: Persistence",
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"Tactic: Privilege Escalation",
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"Tactic: Execution",
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"Data Source: Elastic Endgame",
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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 = "new_terms"
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type = "eql"
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query = '''
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host.os.type : "linux" and event.action : (
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change or file_modify_event or creation or file_create_event or rename or file_rename_event
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) and file.path : (
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/etc/cron.allow or /etc/cron.deny or /etc/cron.d/* or /etc/cron.hourly/* or /etc/cron.daily/* or /etc/cron.weekly/* or
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/etc/cron.monthly/* or /etc/crontab or /usr/sbin/cron or /usr/sbin/anacron or /var/spool/cron/crontabs/*
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file where host.os.type == "linux" and
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event.action in ("rename", "creation") and file.path : (
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"/etc/cron.allow", "/etc/cron.deny", "/etc/cron.d/*", "/etc/cron.hourly/*", "/etc/cron.daily/*", "/etc/cron.weekly/*",
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"/etc/cron.monthly/*", "/etc/crontab", "/var/spool/cron/crontabs/*", "/var/spool/anacron/*"
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) and not (
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(process.name : (
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dpkg or dockerd or rpm or snapd or yum or exe or dnf or podman or dnf-automatic or puppet or autossl_check)
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) or
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(file.extension : (swp or swpx)) or
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(process.name : sed and file.name : sed*) or
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(process.name : perl and file.name : e2scrub_all.tmp*) or
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(process.executable : /var/lib/dpkg*) or
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(file.path:/var/spool/cron/crontabs/tmp.*)
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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/local/bin/dockerd"
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) or
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file.path : "/var/spool/cron/crontabs/tmp.*" 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 : ("/nix/store/*", "/var/lib/dpkg/*", "/tmp/vmis.*", "/snap/*", "/dev/fd/*") or
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process.executable == null or
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(process.name == "sed" and file.name : "sed*") or
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(process.name == "perl" and file.name : "e2scrub_all.tmp*")
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)
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'''
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@@ -251,11 +255,3 @@ reference = "https://attack.mitre.org/techniques/T1053/003/"
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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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[rule.new_terms]
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field = "new_terms_fields"
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value = ["host.id", "file.path", "process.executable"]
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[[rule.new_terms.history_window_start]]
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field = "history_window_start"
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value = "now-10d"
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Reference in New Issue
Block a user