Vulnerabilities > CVE-2020-7455 - Missing Release of Resource after Effective Lifetime vulnerability in Freebsd 11.3/11.4/12.1

047910
CVSS 2.1 - LOW
Attack vector
LOCAL
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
PARTIAL
Integrity impact
NONE
Availability impact
NONE
local
low complexity
freebsd
CWE-772
nessus

Summary

In FreeBSD 12.1-STABLE before r360973, 12.1-RELEASE before p5, 11.4-STABLE before r360973, 11.4-BETA1 before p1 and 11.3-RELEASE before p9, the FTP packet handler in libalias incorrectly calculates some packet length allowing disclosure of small amounts of kernel (for kernel NAT) or natd process space (for userspace natd).

Vulnerable Configurations

Part Description Count
OS
Freebsd
16

Common Attack Pattern Enumeration and Classification (CAPEC)

  • HTTP DoS
    An attacker performs flooding at the HTTP level to bring down only a particular web application rather than anything listening on a TCP/IP connection. This denial of service attack requires substantially fewer packets to be sent which makes DoS harder to detect. This is an equivalent of SYN flood in HTTP. The idea is to keep the HTTP session alive indefinitely and then repeat that hundreds of times. This attack targets resource depletion weaknesses in web server software. The web server will wait to attacker's responses on the initiated HTTP sessions while the connection threads are being exhausted.

Nessus

NASL familyFreeBSD Local Security Checks
NASL idFREEBSD_PKG_78992249947C11EA92AB00163E433440.NASL
descriptionThe FTP packet handler in libalias incorrectly calculates some packet lengths. This may result in disclosing small amounts of memory from the kernel (for the in-kernel NAT implementation) or from the process space for natd (for the userspace implementation). Impact : A malicious attacker could send specially constructed packets that exploit the erroneous calculation allowing the attacker to disclose small amount of memory either from the kernel (for the in-kernel NAT implementation) or from the process space for natd (for the userspace implementation).
last seen2020-05-21
modified2020-05-13
plugin id136536
published2020-05-13
reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/136536
titleFreeBSD : FreeBSD -- Memory disclosure vulnerability in libalias (78992249-947c-11ea-92ab-00163e433440)
code
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from the FreeBSD VuXML database :
#
# Copyright 2003-2020 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("compat.inc");

if (description)
{
  script_id(136536);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/05/19");

  script_cve_id("CVE-2020-7455");
  script_xref(name:"FreeBSD", value:"SA-20:13.libalias");

  script_name(english:"FreeBSD : FreeBSD -- Memory disclosure vulnerability in libalias (78992249-947c-11ea-92ab-00163e433440)");
  script_summary(english:"Checks for updated packages in pkg_info output");

  script_set_attribute(
    attribute:"synopsis", 
    value:
"The remote FreeBSD host is missing one or more security-related
updates."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"The FTP packet handler in libalias incorrectly calculates some packet
lengths. This may result in disclosing small amounts of memory from
the kernel (for the in-kernel NAT implementation) or from the process
space for natd (for the userspace implementation). Impact : A
malicious attacker could send specially constructed packets that
exploit the erroneous calculation allowing the attacker to disclose
small amount of memory either from the kernel (for the in-kernel NAT
implementation) or from the process space for natd (for the userspace
implementation)."
  );
  # https://vuxml.freebsd.org/freebsd/78992249-947c-11ea-92ab-00163e433440.html
  script_set_attribute(
    attribute:"see_also",
    value:"http://www.nessus.org/u?46bc968a"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:N/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-7455");
  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/05/12");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/05/12");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/05/13");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2020 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", "Settings/ParanoidReport");

  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);


if (report_paranoia < 2) audit(AUDIT_PARANOID);

flag = 0;

if (pkg_test(save_report:TRUE, pkg:"FreeBSD>=12.1<12.1_5")) flag++;
if (pkg_test(save_report:TRUE, pkg:"FreeBSD>=11.4<11.4_1")) flag++;
if (pkg_test(save_report:TRUE, pkg:"FreeBSD>=11.3<11.3_9")) 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");