Vulnerabilities > CVE-2016-9836 - Improper Access Control vulnerability in Joomla Joomla!

047910
CVSS 9.8 - CRITICAL
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
HIGH
Integrity impact
HIGH
Availability impact
HIGH
network
low complexity
joomla
CWE-284
critical
nessus

Summary

The file scanning mechanism of JFilterInput::isFileSafe() in Joomla! CMS before 3.6.5 does not consider alternative PHP file extensions when checking uploaded files for PHP content, which enables a user to upload and execute files with the `.php6`, `.php7`, `.phtml`, and `.phpt` extensions. Additionally, JHelperMedia::canUpload() did not blacklist these file extensions as uploadable file types.

Vulnerable Configurations

Part Description Count
Application
Joomla
236

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Embedding Scripts within Scripts
    An attack of this type exploits a programs' vulnerabilities that are brought on by allowing remote hosts to execute scripts. The attacker leverages this capability to execute scripts to execute his/her own script by embedding it within other scripts that the target software is likely to execute. The attacker must have the ability to inject script into script that is likely to be executed. If this is done, then the attacker can potentially launch a variety of probes and attacks against the web server's local environment, in many cases the so-called DMZ, back end resources the web server can communicate with, and other hosts. With the proliferation of intermediaries, such as Web App Firewalls, network devices, and even printers having JVMs and Web servers, there are many locales where an attacker can inject malicious scripts. Since this attack pattern defines scripts within scripts, there are likely privileges to execute said attack on the host. Of course, these attacks are not solely limited to the server side, client side scripts like Ajax and client side JavaScript can contain malicious scripts as well. In general all that is required is for there to be sufficient privileges to execute a script, but not protected against writing.
  • Signature Spoofing by Key Theft
    An attacker obtains an authoritative or reputable signer's private signature key by theft and then uses this key to forge signatures from the original signer to mislead a victim into performing actions that benefit the attacker.

Nessus

  • NASL familyFreeBSD Local Security Checks
    NASL idFREEBSD_PKG_624B45C0C7F311E6AE1B002590263BF5.NASL
    descriptionThe JSST and the Joomla! Security Center report : [20161201] - Core - Elevated Privileges Incorrect use of unfiltered data stored to the session on a form validation failure allows for existing user accounts to be modified; to include resetting their username, password, and user group assignments. [20161202] - Core - Shell Upload Inadequate filesystem checks allowed files with alternative PHP file extensions to be uploaded. [20161203] - Core - Information Disclosure Inadequate ACL checks in the Beez3 com_content article layout override enables a user to view restricted content.
    last seen2020-06-01
    modified2020-06-02
    plugin id96059
    published2016-12-22
    reporterThis script is Copyright (C) 2016-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/96059
    titleFreeBSD : Joomla! -- multiple vulnerabilities (624b45c0-c7f3-11e6-ae1b-002590263bf5)
    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(96059);
      script_version("3.5");
      script_cvs_date("Date: 2019/04/11 17:23:06");
    
      script_cve_id("CVE-2016-9836", "CVE-2016-9837", "CVE-2016-9838");
    
      script_name(english:"FreeBSD : Joomla! -- multiple vulnerabilities (624b45c0-c7f3-11e6-ae1b-002590263bf5)");
      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:
    "The JSST and the Joomla! Security Center report : [20161201] - Core -
    Elevated Privileges Incorrect use of unfiltered data stored to the
    session on a form validation failure allows for existing user accounts
    to be modified; to include resetting their username, password, and
    user group assignments. [20161202] - Core - Shell Upload Inadequate
    filesystem checks allowed files with alternative PHP file extensions
    to be uploaded. [20161203] - Core - Information Disclosure Inadequate
    ACL checks in the Beez3 com_content article layout override enables a
    user to view restricted content."
      );
      # https://developer.joomla.org/security-centre/664-20161201-core-elevated-privileges.html
      script_set_attribute(
        attribute:"see_also",
        value:"http://www.nessus.org/u?7934a324"
      );
      # https://developer.joomla.org/security-centre/665-20161202-core-shell-upload.html
      script_set_attribute(
        attribute:"see_also",
        value:"http://www.nessus.org/u?6c4c5a5e"
      );
      # https://developer.joomla.org/security-centre/666-20161203-core-information-disclosure.html
      script_set_attribute(
        attribute:"see_also",
        value:"http://www.nessus.org/u?a397aea4"
      );
      # https://www.joomla.org/announcements/release-news/5693-joomla-3-6-5-released.html
      script_set_attribute(
        attribute:"see_also",
        value:"http://www.nessus.org/u?3ca7356f"
      );
      # https://vuxml.freebsd.org/freebsd/624b45c0-c7f3-11e6-ae1b-002590263bf5.html
      script_set_attribute(
        attribute:"see_also",
        value:"http://www.nessus.org/u?4b66e4e1"
      );
      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:P/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:H/A:H");
      script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
      script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
      script_set_attribute(attribute:"exploit_available", value:"true");
    
      script_set_attribute(attribute:"plugin_type", value:"local");
      script_set_attribute(attribute:"cpe", value:"p-cpe:/a:freebsd:freebsd:joomla3");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:freebsd:freebsd");
    
      script_set_attribute(attribute:"vuln_publication_date", value:"2016/12/06");
      script_set_attribute(attribute:"patch_publication_date", value:"2016/12/22");
      script_set_attribute(attribute:"plugin_publication_date", value:"2016/12/22");
      script_end_attributes();
    
      script_category(ACT_GATHER_INFO);
      script_copyright(english:"This script is Copyright (C) 2016-2019 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:"joomla3>=1.6.0<3.6.5")) flag++;
    
    if (flag)
    {
      if (report_verbosity > 0) security_hole(port:0, extra:pkg_report_get());
      else security_hole(0);
      exit(0);
    }
    else audit(AUDIT_HOST_NOT, "affected");
    
  • NASL familyCGI abuses
    NASL idJOOMLA_365.NASL
    descriptionAccording to its self-reported version number, the Joomla! installation running on the remote web server is prior to 3.6.5. It is, therefore, affected by multiple vulnerabilities : - A flaw exists in the JFilterInput::isFileSafe() function due to improper validation of file types and extensions of uploaded files before placing them in a user-accessible path. An unauthenticated, remote attacker can exploit this issue, by uploading a specially crafted file using an alternative PHP extension and then requesting it, to execute arbitrary code with the privileges of the web service. Note that this issue affects versions 3.0.0 to 3.6.4. (CVE-2016-9836) - An information disclosure vulnerability exists in the Beez3 com_content article layout override due to inadequate access control list (ACL) checks. An authenticated, remote attacker can exploit this to disclose restricted content. Note that this issue affects versions 3.0.0 to 3.6.4. (CVE-2016-9837) - A privilege escalation vulnerability exists due to improper validation of form data before storing it in the session. An authenticated, remote attacker can exploit this, via a specially crafted request, to modify existing user accounts, such as resetting credentials or group assignments. (CVE-2016-9838) Note that Nessus has not tested for these issues but has instead relied only on the application
    last seen2020-06-01
    modified2020-06-02
    plugin id95916
    published2016-12-16
    reporterThis script is Copyright (C) 2016-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/95916
    titleJoomla! < 3.6.5 Multiple Vulnerabilities
    code
    #
    # (C) Tenable Network Security, Inc.
    #
    
    include("compat.inc");
    
    if (description)
    {
      script_id(95916);
      script_version("1.8");
      script_cvs_date("Date: 2019/11/13");
    
      script_cve_id("CVE-2016-9836", "CVE-2016-9837", "CVE-2016-9838");
      script_bugtraq_id(94663, 94892, 94893);
    
      script_name(english:"Joomla! < 3.6.5 Multiple Vulnerabilities");
      script_summary(english:"Checks the version of Joomla!.");
    
      script_set_attribute(attribute:"synopsis", value:
    "The remote web server contains a PHP application that is affected by
    multiple vulnerabilities.");
      script_set_attribute(attribute:"description", value:
    "According to its self-reported version number, the Joomla!
    installation running on the remote web server is prior to 3.6.5. It
    is, therefore, affected by multiple vulnerabilities :
    
      - A flaw exists in the JFilterInput::isFileSafe() function
        due to improper validation of file types and extensions
        of uploaded files before placing them in a
        user-accessible path. An unauthenticated, remote
        attacker can exploit this issue, by uploading a
        specially crafted file using an alternative PHP
        extension and then requesting it, to execute arbitrary
        code with the privileges of the web service. Note that
        this issue affects versions 3.0.0 to 3.6.4.
        (CVE-2016-9836)
    
      - An information disclosure vulnerability exists in the
        Beez3 com_content article layout override due to
        inadequate access control list (ACL) checks. An
        authenticated, remote attacker can exploit this to
        disclose restricted content. Note that this issue
        affects versions 3.0.0 to 3.6.4. (CVE-2016-9837)
    
      - A privilege escalation vulnerability exists due to
        improper validation of form data before storing it in
        the session. An authenticated, remote attacker can
        exploit this, via a specially crafted request, to modify
        existing user accounts, such as resetting credentials or
        group assignments. (CVE-2016-9838)
    
    Note that Nessus has not tested for these issues but has instead
    relied only on the application's self-reported version number.");
      # https://www.joomla.org/announcements/release-news/5693-joomla-3-6-5-released.html
      script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?3ca7356f");
      # https://developer.joomla.org/security-centre/664-20161201-core-elevated-privileges.html
      script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?7934a324");
      # https://developer.joomla.org/security-centre/665-20161202-core-shell-upload.html
      script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?6c4c5a5e");
      # https://developer.joomla.org/security-centre/666-20161203-core-information-disclosure.html
      script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?a397aea4");
      script_set_attribute(attribute:"solution", value:
    "Upgrade to Joomla! version 3.6.5 or later.");
      script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");
      script_set_cvss_temporal_vector("CVSS2#E:F/RL:U/RC:ND");
      script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
      script_set_cvss3_temporal_vector("CVSS:3.0/E:F/RL:U/RC:X");
      script_set_attribute(attribute:"cvss_score_source", value:"CVE-2016-9836");
    
      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:"2016/10/27");
      script_set_attribute(attribute:"patch_publication_date", value:"2016/12/13");
      script_set_attribute(attribute:"plugin_publication_date", value:"2016/12/16");
    
      script_set_attribute(attribute:"potential_vulnerability", value:"true");
      script_set_attribute(attribute:"plugin_type", value:"remote");
      script_set_attribute(attribute:"cpe", value:"cpe:/a:joomla:joomla\!");
      script_end_attributes();
    
      script_category(ACT_GATHER_INFO);
      script_family(english:"CGI abuses");
    
      script_copyright(english:"This script is Copyright (C) 2016-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");
    
      script_dependencies("joomla_detect.nasl");
      script_require_keys("installed_sw/Joomla!", "www/PHP", "Settings/ParanoidReport");
      script_require_ports("Services/www", 80);
    
      exit(0);
    }
    
    include("audit.inc");
    include("global_settings.inc");
    include("http.inc");
    include("install_func.inc");
    include("misc_func.inc");
    
    app = "Joomla!";
    get_install_count(app_name:app, exit_if_zero:TRUE);
    
    port = get_http_port(default:80, php:TRUE);
    
    install = get_single_install(
      app_name : app,
      port     : port,
      exit_if_unknown_ver : TRUE
    );
    
    #if (report_paranoia < 2) audit(AUDIT_PARANOID);
    
    dir = install["path"];
    install_loc =  build_url(port:port, qs:dir);
    version = install['version'];
    
    fix = "3.6.5";
    
    # Pull out the purely numeric version
    numeric = eregmatch(string:version, pattern:"^([0-9\.]+)($|[^0-9])");
    
    if (empty_or_null(numeric))
      audit(AUDIT_UNKNOWN_WEB_APP_VER, app, install_loc);
    
    numeric = numeric[1];
    
    parts = split(numeric, sep:".", keep:FALSE);
    
    if (len(parts) < 3) audit(AUDIT_VER_NOT_GRANULAR, app, version);
    
    # Version 1.6.0 - 3.6.4 vulnerable to privilege escalation
    # https://developer.joomla.org/security-centre/664-20161201-core-elevated-privileges.html
    if (ver_compare(ver:numeric, minver:"1.6.0", fix:fix, strict:FALSE) < 0)
    {
      report =
        '\n  URL               : ' +install_loc+
        '\n  Installed version : ' +version+
        '\n  Fixed version     : ' +fix+
        '\n';
    
      security_report_v4(
        port:port,
        extra:report,
        severity:SECURITY_HOLE);
    }
    else audit(AUDIT_WEB_APP_NOT_AFFECTED, app, install_loc, version);