Configure Audit Rules for File System Mounting

# 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("1.3.6.1.4.1.25623.1.0.130280");
  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 11:44:17 +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("Configure Audit Rules for File System Mounting");

  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_openeuler");

  script_xref(name:"Policy", value:"EulerOS Baseline: openEuler Security Configuration Baseline (v1.0.0): 4. Log Audit: 4.1 Audit: 4.1.21 Configure Audit Rules for File System Mounting (Recommendation)");
  script_xref(name:"Policy", value:"openEuler Baseline: openEuler Security Configuration Baseline (v1.0.0): 4. Log Audit: 4.1 Audit: 4.1.21 Configure Audit Rules for File System Mounting (Recommendation)");

  script_tag(name:"summary", value:"Generally, for deployed services, the file system mounting does
not change. Therefore, any change in the file system mounting may indicate attacks. For file
systems with changes in mounting, audit and monitor their mounting conditions for tracing.

By default, audit rules for file system mounting are not configured in openEuler. You are advised
to configure rules based on the actual service scenario.");

  exit(0);
}

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

title = "Configure Audit Rules for File System Mounting";

solution = "For a 32-bit system, create a rule file, for example, mount.rules, in the
/etc/audit/rules.d/ directory, and add audit rules to the file. indicates the value of UID_MIN in
the /etc/login.defs file. The default value is 1000 on openEuler.

# vim /etc/audit/rules.d/mount.rules
-a always,exit -F arch=b32 -S mount -F auid>= -F auid!=unset -k

For a 64-bit system, add configuration related to arch=b64:

-a always,exit -F arch=b64 -S mount -F auid>= -F auid!=unset -k

To ensure compatibility, the configuration related to arch=b32 in the 64-bit system must be
retained. Restart the auditd service for the rules to take effect.

# service auditd restart
Stopping logging: [ OK ]
Redirecting start to /bin/systemctl start auditd.service";

check_type = "SSH_Cmd";

action = 'Run the command in the terminal:
# auditctl -l 2>/dev/null | grep -iE "\\-S\\s*mount"';

expected_value = 'The output should not 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 : Check mount in auditctl
# ------------------------------------------------------------------

step_cmd = 'auditctl -l 2>/dev/null | grep -iE "\\-S\\s*mount"';
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);