Do Not Allow Unused Users

# SPDX-FileCopyrightText: 2025 Greenbone AG
# Some text descriptions might be excerpted from (a) referenced
# source(s), and are Copyright (C) by the respective right holder(s).
#
# SPDX-License-Identifier: GPL-2.0-only

# ------------------------------------------------------------------
# METADATA
# ------------------------------------------------------------------

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.130381");
  script_version("2025-11-21T05:40:28+0000");
  script_tag(name:"last_modification", value:"2025-11-21 05:40:28 +0000 (Fri, 21 Nov 2025)");
  script_tag(name:"creation_date", value:"2025-05-07 11:45:55 +0000 (Wed, 07 May 2025)");
  script_tag(name:"cvss_base", value:"0.0");
  script_tag(name:"cvss_base_vector", value:"AV:L/AC:H/Au:S/C:N/I:N/A:N");
  script_tag(name:"qod", value:"97");

  script_name("Do Not Allow Unused Users");

  script_category(ACT_GATHER_INFO);
  script_copyright("Copyright (C) 2025 Greenbone AG");
  script_family("Policy");
  script_dependencies("compliance_tests.nasl", "compliance_os_check.nasl");

  script_mandatory_keys("Compliance/Launch", "policy/ssh/login/euleros_eulerosvirtual_openeuler_hce");

  script_xref(name:"Policy", value:"EulerOS Baseline: openEuler Security Configuration Baseline (v1.0.0): 2. Secure Access: 2.1 Users: 2.1.2 Do Not Allow Unused Users (Requirement)");
  script_xref(name:"Policy", value:"EulerOS Virtual: openEuler Security Configuration Baseline (v1.0.0): 2. Secure Access: 2.1 Users: 2.1.2 Do Not Allow Unused Users (Requirement)");
  script_xref(name:"Policy", value:"HCE Linux (Huawei Cloud EulerOS): openEuler Security Configuration Baseline (v1.0.0): 2. Secure Access: 2.1 Users: 2.1.2 Do Not Allow Unused Users (Requirement)");
  script_xref(name:"Policy", value:"openEuler Baseline: openEuler Security Configuration Baseline (v1.0.0): 2. Secure Access: 2.1 Users: 2.1.2 Do Not Allow Unused Users (Requirement)");

  script_tag(name:"summary", value:"If service-irrelevant users exist in the system, attackers may
use them to launch attacks. Only users required by services are retained in the system. Other users
used for installation, deployment, commissioning, verification, and fault locating must be deleted.

By default, unused users do not exist in openEuler.");

  exit(0);
}

include("ssh_func.inc");
include("host_details.inc");
include("policy_reporting_module.inc");

title = "Do Not Allow Unused Users";

solution = "If there are users irrelevant to services, perform the following steps to delete them:

1.Search for all files whose owner is the user and run the rm command to manually delete these
files. (For example, test is the user name. The /home/test directory can be automatically deleted
using an option when the user is deleted. xxx indicates the file or directory to be deleted.)

# find / -user test
# rm xxx -rf

2.Delete a user, including the home directory.
# userdel -rf test";

check_type = "SSH_Cmd";

action = 'Run the command in the terminal:
# awk -F: \'(\\$3>=1000){print \\$1}\' /etc/passwd | grep -v "^nobody$"';

expected_value = 'The output should be empty';

# ------------------------------------------------------------------
# CONNECTION CHECK
# ------------------------------------------------------------------

if(!get_kb_item("login/SSH/success") || !sock = ssh_login_or_reuse_connection()){

  report_ssh_error(title: title,
                   solution: solution,
                   action: action,
                   expected_value: expected_value,
                   check_type: check_type);
  exit(0);
}

# ------------------------------------------------------------------
# CHECK : Verify Command `awk -F: '($3>=1000){print $1}' /etc/passwd | grep -v "^nobody$"`
# ------------------------------------------------------------------

step_cmd = 'awk -F: \'(\\$3>=1000){print \\$1}\' /etc/passwd | grep -v "^nobody$"';
actual_value = ssh_cmd(socket:sock, cmd:step_cmd, return_errors:TRUE, return_linux_errors_only:TRUE);

if(eregmatch(string: actual_value, pattern:"(No such file or directory|Permission denied|Command not found|Segmentation fault|service not found|is not running|syntax error near unexpected token|syntax error: unexpected end of file)", icase: TRUE)){
  compliant = "incomplete";
  comment = "Something went wrong during the audit check. Please try again.";
}else if(!actual_value){
  compliant = "yes";
  comment = "Check passed";
}else{
  compliant = "no";
  comment = "Check failed";
}

# ------------------------------------------------------------------
# REPORT
# ------------------------------------------------------------------

target = get_kb_item("policy/ssh/login/os-release");
comment = "Target: " + target + "\n" + comment;

report_audit(action: action,
             actual_value: actual_value,
             expected_value: expected_value,
             is_compliant: compliant,
             solution: solution,
             check_type: check_type,
             title: title,
             comment: comment);

exit(0);