FreeBSD : ElGamal sign+encrypt keys created by GnuPG can be compromised (81313647-2d03-11d8-9355-0020ed76ef5a)

#%NASL_MIN_LEVEL 70300
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from the FreeBSD VuXML database :
#
# Copyright 2003-2018 Jacques Vidrine and contributors
#
# Redistribution and use in source (VuXML) and 'compiled' forms (SGML,
# HTML, PDF, PostScript, RTF and so forth) with or without modification,
# are permitted provided that the following conditions are met:
# 1. Redistributions of source code (VuXML) must retain the above
#    copyright notice, this list of conditions and the following
#    disclaimer as the first lines of this file unmodified.
# 2. Redistributions in compiled form (transformed to other DTDs,
#    published online in any format, converted to PDF, PostScript,
#    RTF and other formats) must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer
#    in the documentation and/or other materials provided with the
#    distribution.
# 
# THIS DOCUMENTATION IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
# OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
# OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
# BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
# OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS DOCUMENTATION,
# EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#

include('deprecated_nasl_level.inc');
include('compat.inc');

if (description)
{
  script_id(36752);
  script_version("1.11");
  script_set_attribute(attribute:"plugin_modification_date", value:"2021/01/06");

  script_cve_id("CVE-2003-0971");

  script_name(english:"FreeBSD : ElGamal sign+encrypt keys created by GnuPG can be compromised (81313647-2d03-11d8-9355-0020ed76ef5a)");
  script_summary(english:"Checks for updated package in pkg_info output");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote FreeBSD host is missing a security-related update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"Any ElGamal sign+encrypt keys created by GnuPG contain a cryptographic
weakness that may allow someone to obtain the private key. These keys
should be considered unusable and should be revoked.

The following summary was written by Werner Koch, GnuPG author :

Phong Nguyen identified a severe bug in the way GnuPG creates and uses
ElGamal keys for signing. This is a significant security failure which
can lead to a compromise of almost all ElGamal keys used for signing.
Note that this is a real world vulnerability which will reveal your
private key within a few seconds.

...

Please take immediate action and revoke your ElGamal signing keys.
Furthermore you should take whatever measures necessary to limit the
damage done for signed or encrypted documents using that key.

Note that the standard keys as generated by GnuPG (DSA and ElGamal
encryption) as well as RSA keys are NOT vulnerable. Note also that
ElGamal signing keys cannot be generated without the use of a special
flag to enable hidden options and even then overriding a warning
message about this key type. See below for details on how to identify
vulnerable keys."
  );
  # http://lists.gnupg.org/pipermail/gnupg-devel/2003-November/020570.html
  script_set_attribute(
    attribute:"see_also",
    value:"http://www.nessus.org/u?a8149f9b"
  );
  # https://vuxml.freebsd.org/freebsd/81313647-2d03-11d8-9355-0020ed76ef5a.html
  script_set_attribute(
    attribute:"see_also",
    value:"http://www.nessus.org/u?e4c18118"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:N/A:N");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:freebsd:freebsd:gnupg");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:freebsd:freebsd");

  script_set_attribute(attribute:"vuln_publication_date", value:"2003/11/27");
  script_set_attribute(attribute:"patch_publication_date", value:"2003/12/12");
  script_set_attribute(attribute:"plugin_publication_date", value:"2009/04/23");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2009-2021 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"FreeBSD Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/FreeBSD/release", "Host/FreeBSD/pkg_info");

  exit(0);
}


include("audit.inc");
include("freebsd_package.inc");


if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (!get_kb_item("Host/FreeBSD/release")) audit(AUDIT_OS_NOT, "FreeBSD");
if (!get_kb_item("Host/FreeBSD/pkg_info")) audit(AUDIT_PACKAGE_LIST_MISSING);


flag = 0;

if (pkg_test(save_report:TRUE, pkg:"gnupg>=1.0.2<1.2.3_4")) flag++;

if (flag)
{
  if (report_verbosity > 0) security_warning(port:0, extra:pkg_report_get());
  else security_warning(0);
  exit(0);
}
else audit(AUDIT_HOST_NOT, "affected");