Potential Shadow File Read via Command Line Utilities

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Potential Shadow File Read via Command Line Utilities

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Identifies access to the /etc/shadow file via the commandline using standard system utilities. After elevating privileges to root, threat actors may attempt to read or dump this file in order to gain valid credentials. They may utilize these to move laterally undetected and access additional resources.

Rule type: eql

Rule indices:

  • auditbeat-*
  • logs-endpoint.events.*

Severity: medium

Risk score: 47

Runs every: 5m

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

  • Elastic
  • Host
  • Linux
  • Threat Detection
  • Privilege Escalation
  • Credential Access

Version: 4

Rule authors:

  • Elastic

Rule license: Elastic License v2

Rule query

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process where host.os.type == "linux" and event.type == "start" and event.action == "exec" and user.name == "root"
  and (process.args : "/etc/shadow" or (process.working_directory: "/etc" and process.args: "shadow"))
  and not process.executable:
    ("/usr/bin/tar",
    "/bin/tar",
    "/usr/bin/gzip",
    "/bin/gzip",
    "/usr/bin/zip",
    "/bin/zip",
    "/usr/bin/stat",
    "/bin/stat",
    "/usr/bin/cmp",
    "/bin/cmp",
    "/usr/bin/sudo",
    "/bin/sudo",
    "/usr/bin/find",
    "/bin/find",
    "/usr/bin/ls",
    "/bin/ls",
    "/usr/bin/uniq",
    "/bin/uniq",
    "/usr/bin/unzip",
    "/bin/unzip",
    "/usr/sbin/restorecon",
    "/sbin/restorecon")
  and not process.parent.executable: "/bin/dracut" and
  not (process.executable : ("/bin/chown", "/usr/bin/chown") and process.args : "root:shadow") and
  not (process.executable : ("/bin/chmod", "/usr/bin/chmod") and process.args : "640")

Framework: MITRE ATT&CKTM