Git Hook Created or Modified

  1[metadata]
  2creation_date = "2024/06/26"
  3integration = ["endpoint"]
  4maturity = "production"
  5updated_date = "2024/10/17"
  6
  7[rule]
  8author = ["Elastic"]
  9description = """
 10This rule detects the creation or modification of a Git hook file on a Linux system. Git hooks are scripts that Git
 11executes before or after events such as commit, push, and receive. They are used to automate tasks, enforce policies,
 12and customize Git's behavior. Attackers can abuse Git hooks to maintain persistence on a system by executing malicious
 13code whenever a specific Git event occurs.
 14"""
 15from = "now-9m"
 16index = ["logs-endpoint.events.file*"]
 17language = "eql"
 18license = "Elastic License v2"
 19name = "Git Hook Created or Modified"
 20references = [
 21    "https://git-scm.com/docs/githooks/2.26.0",
 22    "https://www.elastic.co/security-labs/sequel-on-persistence-mechanisms",
 23]
 24risk_score = 21
 25rule_id = "ac531fcc-1d3b-476d-bbb5-1357728c9a37"
 26setup = """## Setup
 27
 28This rule requires data coming in from Elastic Defend.
 29
 30### Elastic Defend Integration Setup
 31Elastic 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.
 32
 33#### Prerequisite Requirements:
 34- Fleet is required for Elastic Defend.
 35- To configure Fleet Server refer to the [documentation](https://www.elastic.co/guide/en/fleet/current/fleet-server.html).
 36
 37#### The following steps should be executed in order to add the Elastic Defend integration on a Linux System:
 38- Go to the Kibana home page and click "Add integrations".
 39- In the query bar, search for "Elastic Defend" and select the integration to see more details about it.
 40- Click "Add Elastic Defend".
 41- Configure the integration name and optionally add a description.
 42- Select the type of environment you want to protect, either "Traditional Endpoints" or "Cloud Workloads".
 43- 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).
 44- We suggest selecting "Complete EDR (Endpoint Detection and Response)" as a configuration setting, that provides "All events; all preventions"
 45- 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.
 46For more details on Elastic Agent configuration settings, refer to the [helper guide](https://www.elastic.co/guide/en/fleet/8.10/agent-policy.html).
 47- Click "Save and Continue".
 48- 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.
 49For more details on Elastic Defend refer to the [helper guide](https://www.elastic.co/guide/en/security/current/install-endpoint.html).
 50"""
 51severity = "low"
 52tags = [
 53    "Domain: Endpoint",
 54    "OS: Linux",
 55    "Use Case: Threat Detection",
 56    "Tactic: Persistence",
 57    "Tactic: Execution",
 58    "Tactic: Defense Evasion",
 59    "Data Source: Elastic Defend",
 60]
 61timestamp_override = "event.ingested"
 62type = "eql"
 63
 64query = '''
 65file where host.os.type == "linux" and event.type == "creation" and file.path : "*.git/hooks/*" and
 66file.extension == null and process.executable != null and not (
 67  process.executable in (
 68    "/bin/dpkg", "/usr/bin/dpkg", "/bin/dockerd", "/usr/bin/dockerd", "/usr/sbin/dockerd", "/bin/microdnf",
 69    "/usr/bin/microdnf", "/bin/rpm", "/usr/bin/rpm", "/bin/snapd", "/usr/bin/snapd", "/bin/yum", "/usr/bin/yum",
 70    "/bin/dnf", "/usr/bin/dnf", "/bin/podman", "/usr/bin/podman", "/bin/dnf-automatic", "/usr/bin/dnf-automatic",
 71    "/bin/pacman", "/usr/bin/pacman", "/usr/bin/dpkg-divert", "/bin/dpkg-divert", "/sbin/apk", "/usr/sbin/apk",
 72    "/usr/local/sbin/apk", "/usr/bin/apt", "/usr/sbin/pacman", "/bin/podman", "/usr/bin/podman", "/usr/bin/puppet",
 73    "/bin/puppet", "/opt/puppetlabs/puppet/bin/puppet", "/usr/bin/chef-client", "/bin/chef-client",
 74    "/bin/autossl_check", "/usr/bin/autossl_check", "/proc/self/exe", "/usr/bin/pamac-daemon", "/bin/pamac-daemon",
 75    "/usr/local/bin/dockerd", "/sbin/dockerd"
 76  ) or
 77  process.executable : ("/nix/store/*", "/var/lib/dpkg/*", "/snap/*", "/dev/fd/*") or
 78  process.name in ("git", "dirname", "tar", "gitea", "git-lfs") or
 79  (process.name == "sed" and file.name : "sed*") or
 80  (process.name == "perl" and file.name : "e2scrub_all.tmp*") 
 81)
 82'''
 83
 84[[rule.threat]]
 85framework = "MITRE ATT&CK"
 86
 87[[rule.threat.technique]]
 88id = "T1543"
 89name = "Create or Modify System Process"
 90reference = "https://attack.mitre.org/techniques/T1543/"
 91
 92[[rule.threat.technique]]
 93id = "T1574"
 94name = "Hijack Execution Flow"
 95reference = "https://attack.mitre.org/techniques/T1574/"
 96
 97[rule.threat.tactic]
 98id = "TA0003"
 99name = "Persistence"
100reference = "https://attack.mitre.org/tactics/TA0003/"
101
102[[rule.threat]]
103framework = "MITRE ATT&CK"
104
105[[rule.threat.technique]]
106id = "T1059"
107name = "Command and Scripting Interpreter"
108reference = "https://attack.mitre.org/techniques/T1059/"
109
110[[rule.threat.technique.subtechnique]]
111id = "T1059.004"
112name = "Unix Shell"
113reference = "https://attack.mitre.org/techniques/T1059/004/"
114
115[rule.threat.tactic]
116id = "TA0002"
117name = "Execution"
118reference = "https://attack.mitre.org/tactics/TA0002/"
119
120[[rule.threat]]
121framework = "MITRE ATT&CK"
122
123[rule.threat.tactic]
124id = "TA0005"
125name = "Defense Evasion"
126reference = "https://attack.mitre.org/tactics/TA0005/"