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nessusThis script is Copyright (C) 2021-2023 and is owned by Tenable, Inc. or an Affiliate thereof.FREEBSD_PKG_D22B336D056711ECB69D4062311215D5.NASL
HistoryAug 26, 2021 - 12:00 a.m.

FreeBSD : FreeBSD -- libfetch out of bounds read (d22b336d-0567-11ec-b69d-4062311215d5)

2021-08-2600:00:00
This script is Copyright (C) 2021-2023 and is owned by Tenable, Inc. or an Affiliate thereof.
www.tenable.com
10

6.4 Medium

CVSS2

Attack Vector

NETWORK

Attack Complexity

LOW

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

NONE

Availability Impact

PARTIAL

AV:N/AC:L/Au:N/C:P/I:N/A:P

9.1 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

9.3 High

AI Score

Confidence

High

0.004 Low

EPSS

Percentile

73.4%

The passive mode in FTP communication allows an out of boundary read while libfetch uses strtol to parse the relevant numbers into address bytes. It does not check if the line ends prematurely. If it does, the for-loop condition checks for *p == ‘\0’ one byte too late because p++ was already performed. Impact : The connection buffer size can be controlled by a malicious FTP server because the size is increased until a newline is encountered (or no more characters are read). This also allows to move the buffer into more interesting areas within the address space, potentially parsing relevant numbers for the attacker.
Since these bytes become available to the server in form of a new TCP connection to a constructed port number or even part of the IPv6 address this is a potential information leak.

#%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 2003-2021 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(152857);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/12/01");

  script_cve_id("CVE-2021-36159");
  script_xref(name:"FreeBSD", value:"SA-21:15.libfetch");

  script_name(english:"FreeBSD : FreeBSD -- libfetch out of bounds read (d22b336d-0567-11ec-b69d-4062311215d5)");

  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 passive mode in FTP communication allows an out of boundary read
while libfetch uses strtol to parse the relevant numbers into address
bytes. It does not check if the line ends prematurely. If it does, the
for-loop condition checks for *p == '\0' one byte too late because p++
was already performed. Impact : The connection buffer size can be
controlled by a malicious FTP server because the size is increased
until a newline is encountered (or no more characters are read). This
also allows to move the buffer into more interesting areas within the
address space, potentially parsing relevant numbers for the attacker.
Since these bytes become available to the server in form of a new TCP
connection to a constructed port number or even part of the IPv6
address this is a potential information leak.");
  # https://vuxml.freebsd.org/freebsd/d22b336d-0567-11ec-b69d-4062311215d5.html
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?f7e8824d");
  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:P");
  script_set_cvss_temporal_vector("CVSS2#E:POC/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:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-36159");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2021/08/24");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/08/25");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/08/26");

  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:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"FreeBSD Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2021-2023 and is owned by Tenable, Inc. or an Affiliate thereof.");

  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>=13.0<13.0_4")) flag++;
if (pkg_test(save_report:TRUE, pkg:"FreeBSD>=12.2<12.2_10")) flag++;
if (pkg_test(save_report:TRUE, pkg:"FreeBSD>=11.4<11.4_13")) 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");
VendorProductVersionCPE
freebsdfreebsdfreebsdp-cpe:/a:freebsd:freebsd:freebsd
freebsdfreebsdcpe:/o:freebsd:freebsd

6.4 Medium

CVSS2

Attack Vector

NETWORK

Attack Complexity

LOW

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

NONE

Availability Impact

PARTIAL

AV:N/AC:L/Au:N/C:P/I:N/A:P

9.1 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

9.3 High

AI Score

Confidence

High

0.004 Low

EPSS

Percentile

73.4%

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