Vulnerabilities > CVE-2018-6920 - Information Exposure vulnerability in Freebsd

047910
CVSS 5.5 - MEDIUM
Attack vector
LOCAL
Attack complexity
LOW
Privileges required
LOW
Confidentiality impact
HIGH
Integrity impact
NONE
Availability impact
NONE
local
low complexity
freebsd
CWE-200
nessus

Summary

In FreeBSD before 11.1-STABLE(r332303), 11.1-RELEASE-p10, 10.4-STABLE(r332321), and 10.4-RELEASE-p9, due to insufficient initialization of memory copied to userland in the Linux subsystem and Atheros wireless driver, small amounts of kernel memory may be disclosed to userland processes. Unprivileged authenticated local users may be able to access small amounts of privileged kernel data.

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Subverting Environment Variable Values
    The attacker directly or indirectly modifies environment variables used by or controlling the target software. The attacker's goal is to cause the target software to deviate from its expected operation in a manner that benefits the attacker.
  • Footprinting
    An attacker engages in probing and exploration activity to identify constituents and properties of the target. Footprinting is a general term to describe a variety of information gathering techniques, often used by attackers in preparation for some attack. It consists of using tools to learn as much as possible about the composition, configuration, and security mechanisms of the targeted application, system or network. Information that might be collected during a footprinting effort could include open ports, applications and their versions, network topology, and similar information. While footprinting is not intended to be damaging (although certain activities, such as network scans, can sometimes cause disruptions to vulnerable applications inadvertently) it may often pave the way for more damaging attacks.
  • Exploiting Trust in Client (aka Make the Client Invisible)
    An attack of this type exploits a programs' vulnerabilities in client/server communication channel authentication and data integrity. It leverages the implicit trust a server places in the client, or more importantly, that which the server believes is the client. An attacker executes this type of attack by placing themselves in the communication channel between client and server such that communication directly to the server is possible where the server believes it is communicating only with a valid client. There are numerous variations of this type of attack.
  • Browser Fingerprinting
    An attacker carefully crafts small snippets of Java Script to efficiently detect the type of browser the potential victim is using. Many web-based attacks need prior knowledge of the web browser including the version of browser to ensure successful exploitation of a vulnerability. Having this knowledge allows an attacker to target the victim with attacks that specifically exploit known or zero day weaknesses in the type and version of the browser used by the victim. Automating this process via Java Script as a part of the same delivery system used to exploit the browser is considered more efficient as the attacker can supply a browser fingerprinting method and integrate it with exploit code, all contained in Java Script and in response to the same web page request by the browser.
  • Session Credential Falsification through Prediction
    This attack targets predictable session ID in order to gain privileges. The attacker can predict the session ID used during a transaction to perform spoofing and session hijacking.

Nessus

NASL familyFirewalls
NASL idPFSENSE_SA-18_05.NASL
descriptionAccording to its self-reported version number, the remote pfSense install is a version 2.3.x prior to 2.3.5-p2 or 2.4.x prior to 2.4.3-p1. It is, therefore, affected by multiple vulnerabilities: - In FreeBSD before 11.1-STABLE(r332066) and 11.1-RELEASE-p10, due to insufficient initialization of memory copied to userland in the network subsystem, small amounts of kernel memory may be disclosed to userland processes. Unprivileged authenticated local users may be able to access small amounts of privileged kernel data. (CVE-2018-6921) - A statement in the System Programming Guide of the Intel 64 and IA-32 Architectures Software Developer
last seen2020-06-01
modified2020-06-02
plugin id119886
published2018-12-27
reporterThis script is Copyright (C) 2018-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/119886
titlepfSense 2.3.x < 2.3.5-p2 / 2.4.x < 2.4.3-p1 Multiple Vulnerabilities (SA-18_04 / SA-18_05)
code
#
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(119886);
  script_version("1.3");
  script_cvs_date("Date: 2019/04/05 23:25:05");

  script_cve_id(
    "CVE-2018-6920",
    "CVE-2018-6921",
    "CVE-2018-8897"
  );

  script_name(english:"pfSense 2.3.x < 2.3.5-p2 / 2.4.x < 2.4.3-p1 Multiple Vulnerabilities (SA-18_04 / SA-18_05)");
  script_summary(english:"Checks the version of pfSense.");

  script_set_attribute(attribute:"synopsis", value:
"The remote firewall host is affected by multiple
vulnerabilities.");
  script_set_attribute(attribute:"description", value:
"According to its self-reported version number, the remote pfSense
install is a version 2.3.x prior to 2.3.5-p2 or 2.4.x prior to
2.4.3-p1. It is, therefore, affected by multiple vulnerabilities:

 - In FreeBSD before 11.1-STABLE(r332066) and 11.1-RELEASE-p10, due
   to insufficient initialization of memory copied to userland in 
   the network subsystem, small amounts of kernel memory may be 
   disclosed to userland processes. Unprivileged authenticated 
   local users may be able to access small amounts of privileged 
   kernel data. (CVE-2018-6921)
   
 - A statement in the System Programming Guide of the Intel 64 and 
   IA-32 Architectures Software Developer's Manual (SDM) was 
   mishandled in the development of some or all operating-system 
   kernels, resulting in unexpected behavior for #DB exceptions that
    could lead to local privilege escalation. (CVE-2018-8897)");
  # https://www.pfsense.org/security/advisories/pfSense-SA-18_05.webgui.asc
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?74fc852c");
  # https://www.pfsense.org/security/advisories/pfSense-SA-18_04.webgui.asc
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?3dd41163");
  # https://www.netgate.com/docs/pfsense/releases/2-3-5-p2-new-features-and-changes.html
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?4a4454c4");
  script_set_attribute(attribute:"solution", value:
"Upgrade to pfSense version 2.3.5-p2 / 2.4.3-p1 or later.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:H/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:H/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2018-8897");
  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"exploited_by_malware", value:"true");
  script_set_attribute(attribute:"metasploit_name", value:'Microsoft Windows POP/MOV SS Local Privilege Elevation Vulnerability');
  script_set_attribute(attribute:"exploit_framework_metasploit", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2018/05/01");
  script_set_attribute(attribute:"patch_publication_date", value:"2018/05/01");
  script_set_attribute(attribute:"plugin_publication_date", value:"2018/12/27");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:pfsense:pfsense");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:bsdperimeter:pfsense");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Firewalls");

  script_copyright(english:"This script is Copyright (C) 2018-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("pfsense_detect.nbin");
  script_require_keys("Host/pfSense");

  exit(0);
}

include("vcf.inc");
include("vcf_extras.inc");

if (!get_kb_item("Host/pfSense")) audit(AUDIT_HOST_NOT, "pfSense");

app_info = vcf::pfsense::get_app_info();
constraints = [
  { "min_version" : "2.4.0", "fixed_version" : "2.4.3-p1"},
  { "min_version" : "2.3.0", "fixed_version" : "2.3.5-p2"}
];

vcf::pfsense::check_version_and_report(
  app_info:app_info,
  constraints:constraints,
  severity:SECURITY_HOLE,
  flags:{xss:TRUE}
);