Linux: SGID files

# Copyright (C) 2019 Greenbone Networks GmbH
# 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-or-later
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.109822");
  script_version("2021-05-18T12:49:08+0000");
  script_tag(name:"last_modification", value:"2021-05-18 12:49:08 +0000 (Tue, 18 May 2021)");
  script_tag(name:"creation_date", value:"2019-03-18 11:05:45 +0100 (Mon, 18 Mar 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: SGID files");

  script_category(ACT_GATHER_INFO);
  script_copyright("Copyright (C) 2019 Greenbone Networks GmbH");
  script_family("Policy");
  script_dependencies("gather-package-list.nasl", "compliance_tests.nasl");
  script_mandatory_keys("Compliance/Launch");
  script_exclude_keys("ssh/no_linux_shell");

  script_add_preference(name:"Files with SGID", type:"entry", value:"", id:1); # Keep for legacy reasons

  script_xref(name:"URL", value:"https://linoxide.com/how-tos/stickbit-suid-guid/");
  script_xref(name:"Policy", value:"CIS Distribution Independent Linux v2.0.0: 6.1.14 Audit SGID executables (Not Scored)");
  script_xref(name:"Policy", value:"CIS CentOS Linux 8 Benchmark v1.0.0: 6.1.14 Audit SGID executables (Not Scored)");
  script_xref(name:"Policy", value:"CIS Controls Version 7: 5.1 Establish Secure Configurations");

  script_tag(name:"summary", value:"When the SGID (set group ID) bit is set on an executable, it
executes with the GID of the owner. This may be intended for some executables. Add files with SGID
bit which should be allowed to have this bit set in the preference.

This script checks if any other local files than the given have the SGID bit set.");

  exit(0);
}

include("ssh_func.inc");
include("policy_functions.inc");

cmd = "df --local -P | awk '{if (NR!=1) print $6}' | xargs -I '{}' find '{}' -xdev -type f -perm -2000";
title = "SGID executables";
solution = "Ensure that no rogue SGID programs have been introduced into the system. Review the
files returned by the action in the Audit section and confirm the integrity of these binaries.";
test_type = "Manual Check";
default = "None";
compliant = "incomplete";

if(!get_kb_item("login/SSH/success") || !sock = ssh_login_or_reuse_connection()){
  value = "Error";
  comment = "No SSH connection";
}else if(!value = ssh_cmd(cmd:cmd, socket:sock, nosh:TRUE)){
  value = "None";
  comment = "Command did not return anything";
}else{
  comment = "Please check the value manually";
}

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);