Vulnerabilities > CVE-2015-1417 - Resource Exhaustion vulnerability in Freebsd

047910
CVSS 5.0 - MEDIUM
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
NONE
Availability impact
PARTIAL
network
low complexity
freebsd
CWE-400
nessus

Summary

The inet module in FreeBSD 10.2x before 10.2-PRERELEASE, 10.2-BETA2-p2, 10.2-RC1-p1, 10.1x before 10.1-RELEASE-p16, 9.x before 9.3-STABLE, 9.3-RELEASE-p21, and 8.x before 8.4-STABLE, 8.4-RELEASE-p35 on systems with VNET enabled and at least 16 VNET instances allows remote attackers to cause a denial of service (mbuf consumption) via multiple concurrent TCP connections.

Vulnerable Configurations

Part Description Count
OS
Freebsd
56

Common Attack Pattern Enumeration and Classification (CAPEC)

  • XML Ping of the Death
    An attacker initiates a resource depletion attack where a large number of small XML messages are delivered at a sufficiently rapid rate to cause a denial of service or crash of the target. Transactions such as repetitive SOAP transactions can deplete resources faster than a simple flooding attack because of the additional resources used by the SOAP protocol and the resources necessary to process SOAP messages. The transactions used are immaterial as long as they cause resource utilization on the target. In other words, this is a normal flooding attack augmented by using messages that will require extra processing on the target.
  • XML Entity Expansion
    An attacker submits an XML document to a target application where the XML document uses nested entity expansion to produce an excessively large output XML. XML allows the definition of macro-like structures that can be used to simplify the creation of complex structures. However, this capability can be abused to create excessive demands on a processor's CPU and memory. A small number of nested expansions can result in an exponential growth in demands on memory.
  • Inducing Account Lockout
    An attacker leverages the security functionality of the system aimed at thwarting potential attacks to launch a denial of service attack against a legitimate system user. Many systems, for instance, implement a password throttling mechanism that locks an account after a certain number of incorrect log in attempts. An attacker can leverage this throttling mechanism to lock a legitimate user out of their own account. The weakness that is being leveraged by an attacker is the very security feature that has been put in place to counteract attacks.
  • Violating Implicit Assumptions Regarding XML Content (aka XML Denial of Service (XDoS))
    XML Denial of Service (XDoS) can be applied to any technology that utilizes XML data. This is, of course, most distributed systems technology including Java, .Net, databases, and so on. XDoS is most closely associated with web services, SOAP, and Rest, because remote service requesters can post malicious XML payloads to the service provider designed to exhaust the service provider's memory, CPU, and/or disk space. The main weakness in XDoS is that the service provider generally must inspect, parse, and validate the XML messages to determine routing, workflow, security considerations, and so on. It is exactly these inspection, parsing, and validation routines that XDoS targets. There are three primary attack vectors that XDoS can navigate Target CPU through recursion: attacker creates a recursive payload and sends to service provider Target memory through jumbo payloads: service provider uses DOM to parse XML. DOM creates in memory representation of XML document, but when document is very large (for example, north of 1 Gb) service provider host may exhaust memory trying to build memory objects. XML Ping of death: attack service provider with numerous small files that clog the system. All of the above attacks exploit the loosely coupled nature of web services, where the service provider has little to no control over the service requester and any messages the service requester sends.

Nessus

NASL familyFreeBSD Local Security Checks
NASL idFREEBSD_PKG_0CB9D5BB600A11E6A6C314DAE9D210B8.NASL
descriptionThere is a mistake with the introduction of VNET, which converted the global limit on the number of segments that could belong to reassembly queues into a per-VNET limit. Because mbufs are allocated from a global pool, in the presence of a sufficient number of VNETs, the total number of mbufs attached to reassembly queues can grow to the total number of mbufs in the system, at which point all network traffic would cease. Impact : An attacker who can establish concurrent TCP connections across a sufficient number of VNETs and manipulate the inbound packet streams such that the maximum number of mbufs are enqueued on each reassembly queue can cause mbuf cluster exhaustion on the target system, resulting in a Denial of Service condition. As the default per-VNET limit on the number of segments that can belong to reassembly queues is 1/16 of the total number of mbuf clusters in the system, only systems that have 16 or more VNET instances are vulnerable.
last seen2020-06-01
modified2020-06-02
plugin id92891
published2016-08-12
reporterThis script is Copyright (C) 2016-2018 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/92891
titleFreeBSD : FreeBSD -- Resource exhaustion in TCP reassembly (0cb9d5bb-600a-11e6-a6c3-14dae9d210b8)
code
#
# (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("compat.inc");

if (description)
{
  script_id(92891);
  script_version("2.5");
  script_cvs_date("Date: 2018/12/07  9:46:53");

  script_cve_id("CVE-2015-1417");
  script_xref(name:"FreeBSD", value:"SA-15:15.tcp");

  script_name(english:"FreeBSD : FreeBSD -- Resource exhaustion in TCP reassembly (0cb9d5bb-600a-11e6-a6c3-14dae9d210b8)");
  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:
"There is a mistake with the introduction of VNET, which converted the
global limit on the number of segments that could belong to reassembly
queues into a per-VNET limit. Because mbufs are allocated from a
global pool, in the presence of a sufficient number of VNETs, the
total number of mbufs attached to reassembly queues can grow to the
total number of mbufs in the system, at which point all network
traffic would cease. Impact : An attacker who can establish concurrent
TCP connections across a sufficient number of VNETs and manipulate the
inbound packet streams such that the maximum number of mbufs are
enqueued on each reassembly queue can cause mbuf cluster exhaustion on
the target system, resulting in a Denial of Service condition.

As the default per-VNET limit on the number of segments that can
belong to reassembly queues is 1/16 of the total number of mbuf
clusters in the system, only systems that have 16 or more VNET
instances are vulnerable."
  );
  # https://vuxml.freebsd.org/freebsd/0cb9d5bb-600a-11e6-a6c3-14dae9d210b8.html
  script_set_attribute(
    attribute:"see_also",
    value:"http://www.nessus.org/u?45bba7aa"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H");

  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:"2015/07/28");
  script_set_attribute(attribute:"patch_publication_date", value:"2016/08/11");
  script_set_attribute(attribute:"plugin_publication_date", value:"2016/08/12");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2016-2018 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>=10.1<10.1_16")) flag++;
if (pkg_test(save_report:TRUE, pkg:"FreeBSD>=9.3<9.3_21")) flag++;
if (pkg_test(save_report:TRUE, pkg:"FreeBSD>=8.4<8.4_35")) 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");