Linux: Audit login / logout

# SPDX-FileCopyrightText: 2019 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

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.109779");
  script_version("2023-07-27T05:05:09+0000");
  script_tag(name:"last_modification", value:"2023-07-27 05:05:09 +0000 (Thu, 27 Jul 2023)");
  script_tag(name:"creation_date", value:"2019-02-05 14:45:03 +0100 (Tue, 05 Feb 2019)");
  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("Linux: Audit login / logout");

  script_category(ACT_GATHER_INFO);
  script_copyright("Copyright (C) 2019 Greenbone AG");
  script_family("Policy");
  script_dependencies("compliance_tests.nasl", "read_etc_audit_audit_rules.nasl");
  script_mandatory_keys("Compliance/Launch");

  script_xref(name:"URL", value:"https://linux.die.net/man/7/audit.rules");

  script_tag(name:"summary", value:"Monitoring login and logoff events can provide evidence for
compromised user accounts or brute force attacks.
This script checks if write access to '/var/log/faillog', '/var/log/lastlog' and '/var/log/tallylog'
files is monitored.");

  exit(0);
}

include("policy_functions.inc");

cmd = "grep '*.warning' /etc/rsyslog.conf";
title = "Log all facility messages with warning priority to specified files";
solution = "Add '*.warning FILE' to /etc/rsyslog.conf";
test_type = "SSH_Cmd";
default = "-w /var/log/faillog -p wa -k logins,-w /var/log/lastlog -p wa -k logins,-w /var/log/tallylog -p wa -k logins";

if(get_kb_item("Policy/linux//etc/audit/audit.rules/ERROR")){
  value = "Error";
  compliant = "incomplete";
  comment = "No SSH connection to host";
}else if(get_kb_item("Policy/linux//etc/audit/audit.rules/content/ERROR")){
  value = "Error";
  compliant = "incomplete";
  comment = "Can not read /etc/audit/audit.rules";
}else{
  content = get_kb_item("Policy/linux//etc/audit/audit.rules/content");
  grep = egrep(string:content, pattern:"-w /var/log/(fail|last|tally)log -p wa -k logins");

  foreach line(split(grep)){
    if(line =~ "^\s*#")
      continue;

    value += "," + chomp(line);
  }

  if(value)
    value = str_replace(string:value, find:",", replace:"", count:1);
  else
    value = "None";

  compliant = policy_settings_lists_match(value:value, set_points:default, sep:',');
}

policy_reporting(result:value, default:default, compliant:compliant, fixtext:solution,
  type:test_type, test:cmd, info:comment);
policy_set_kbs(type:test_type, cmd:cmd, default:default, solution:solution, title:title,
  value:value, compliant:compliant);

exit(0);