Vulnerabilities > CVE-2017-17091 - Use of Insufficiently Random Values vulnerability in Wordpress

047910
CVSS 6.5 - MEDIUM
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
SINGLE
Confidentiality impact
PARTIAL
Integrity impact
PARTIAL
Availability impact
PARTIAL
network
low complexity
wordpress
CWE-330
nessus
NVD
Published: 2017-12-02
Updated: 2019-10-03

Summary

wp-admin/user-new.php in WordPress before 4.9.1 sets the newbloguser key to a string that can be directly derived from the user ID, which allows remote attackers to bypass intended access restrictions by entering this string.

Vulnerable Configurations

Part Description Count
Application
Wordpress
642

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Brute Force
    In this attack, some asset (information, functionality, identity, etc.) is protected by a finite secret value. The attacker attempts to gain access to this asset by using trial-and-error to exhaustively explore all the possible secret values in the hope of finding the secret (or a value that is functionally equivalent) that will unlock the asset. Examples of secrets can include, but are not limited to, passwords, encryption keys, database lookup keys, and initial values to one-way functions. The key factor in this attack is the attackers' ability to explore the possible secret space rapidly. This, in turn, is a function of the size of the secret space and the computational power the attacker is able to bring to bear on the problem. If the attacker has modest resources and the secret space is large, the challenge facing the attacker is intractable. While the defender cannot control the resources available to an attacker, they can control the size of the secret space. Creating a large secret space involves selecting one's secret from as large a field of equally likely alternative secrets as possible and ensuring that an attacker is unable to reduce the size of this field using available clues or cryptanalysis. Doing this is more difficult than it sounds since elimination of patterns (which, in turn, would provide an attacker clues that would help them reduce the space of potential secrets) is difficult to do using deterministic machines, such as computers. Assuming a finite secret space, a brute force attack will eventually succeed. The defender must rely on making sure that the time and resources necessary to do so will exceed the value of the information. For example, a secret space that will likely take hundreds of years to explore is likely safe from raw-brute force attacks.
  • Signature Spoofing by Key Recreation
    An attacker obtains an authoritative or reputable signer's private signature key by exploiting a cryptographic weakness in the signature algorithm or pseudorandom number generation and then uses this key to forge signatures from the original signer to mislead a victim into performing actions that benefit the attacker.
  • 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 familyDebian Local Security Checks
    NASL idDEBIAN_DLA-1216.NASL
    descriptionSeveral vulnerabilities were discovered in wordpress, a web blogging tool. The Common Vulnerabilities and Exposures project identifies the following issues. CVE-2017-17091 wp-admin/user-new.php in WordPress sets the newbloguser key to a string that can be directly derived from the user ID, which allows remote attackers to bypass intended access restrictions by entering this string. CVE-2017-17092 wp-includes/functions.php in WordPress does not require the unfiltered_html capability for upload of .js files, which might allow remote attackers to conduct XSS attacks via a crafted file. CVE-2017-17093 wp-includes/general-template.php in WordPress does not properly restrict the lang attribute of an HTML element, which might allow attackers to conduct XSS attacks via the language setting of a site. CVE-2017-17094 wp-includes/feed.php in WordPress does not properly restrict enclosures in RSS and Atom fields, which might allow attackers to conduct XSS attacks via a crafted URL. For Debian 7
    last seen2020-03-17
    modified2017-12-26
    plugin id105423
    published2017-12-26
    reporterThis script is Copyright (C) 2017-2020 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/105423
    titleDebian DLA-1216-1 : wordpress security update
    code
    #%NASL_MIN_LEVEL 80502
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Debian Security Advisory DLA-1216-1. The text
# itself is copyright (C) Software in the Public Interest, Inc.
#

include("compat.inc");

if (description)
{
  script_id(105423);
  script_version("3.6");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/03/12");

  script_cve_id("CVE-2017-17091", "CVE-2017-17092", "CVE-2017-17093", "CVE-2017-17094");

  script_name(english:"Debian DLA-1216-1 : wordpress security update");
  script_summary(english:"Checks dpkg output for the updated packages.");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Debian host is missing a security update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"Several vulnerabilities were discovered in wordpress, a web blogging
tool. The Common Vulnerabilities and Exposures project identifies the
following issues.

CVE-2017-17091

wp-admin/user-new.php in WordPress sets the newbloguser key to a
string that can be directly derived from the user ID, which allows
remote attackers to bypass intended access restrictions by entering
this string.

CVE-2017-17092

wp-includes/functions.php in WordPress does not require the
unfiltered_html capability for upload of .js files, which might allow
remote attackers to conduct XSS attacks via a crafted file.

CVE-2017-17093

wp-includes/general-template.php in WordPress does not properly
restrict the lang attribute of an HTML element, which might allow
attackers to conduct XSS attacks via the language setting of a site.

CVE-2017-17094

wp-includes/feed.php in WordPress does not properly restrict
enclosures in RSS and Atom fields, which might allow attackers to
conduct XSS attacks via a crafted URL.

For Debian 7 'Wheezy', these problems have been fixed in version
3.6.1+dfsg-1~deb7u20.

We recommend that you upgrade your wordpress packages.

NOTE: Tenable Network Security has extracted the preceding description
block directly from the DLA security advisory. Tenable has attempted
to automatically clean and format it as much as possible without
introducing additional issues."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://lists.debian.org/debian-lts-announce/2017/12/msg00019.html"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://packages.debian.org/source/wheezy/wordpress"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Upgrade the affected wordpress, and wordpress-l10n packages."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:P/I:P/A:P");
  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:L/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:wordpress");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:wordpress-l10n");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:7.0");

  script_set_attribute(attribute:"patch_publication_date", value:"2017/12/21");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/12/26");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2017-2020 Tenable Network Security, Inc.");
  script_family(english:"Debian Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/Debian/release", "Host/Debian/dpkg-l");

  exit(0);
}


include("audit.inc");
include("debian_package.inc");


if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (!get_kb_item("Host/Debian/release")) audit(AUDIT_OS_NOT, "Debian");
if (!get_kb_item("Host/Debian/dpkg-l")) audit(AUDIT_PACKAGE_LIST_MISSING);


flag = 0;
if (deb_check(release:"7.0", prefix:"wordpress", reference:"3.6.1+dfsg-1~deb7u20")) flag++;
if (deb_check(release:"7.0", prefix:"wordpress-l10n", reference:"3.6.1+dfsg-1~deb7u20")) flag++;

if (flag)
{
  if (report_verbosity > 0) security_warning(port:0, extra:deb_report_get());
  else security_warning(0);
  exit(0);
}
else audit(AUDIT_HOST_NOT, "affected");
  • NASL familyCGI abuses
    NASL idWORDPRESS_4_9_1.NASL
    descriptionAccording to its self-reported version number, the WordPress application running on the remote web server is prior to 4.9.1. It is, therefore, affected by multiple vulnerabilities.
    last seen2020-06-01
    modified2020-06-02
    plugin id105004
    published2017-12-04
    reporterThis script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/105004
    titleWordPress < 4.9.1 Multiple Vulnerabilities
    code
    #
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(105004);
  script_version("1.11");
  script_cvs_date("Date: 2019/03/29  9:51:59");

  script_cve_id(
    "CVE-2017-17091",
    "CVE-2017-17092",
    "CVE-2017-17093",
    "CVE-2017-17094"
  );
  script_bugtraq_id(102024);

  script_name(english:"WordPress < 4.9.1 Multiple Vulnerabilities");
  script_summary(english:"Checks the version of WordPress.");

  script_set_attribute(attribute:"synopsis", value:
"A PHP application running on the remote web server is affected by
multiple vulnerabilities.");
  script_set_attribute(attribute:"description", value:
"According to its self-reported version number, the WordPress
application running on the remote web server is prior to 4.9.1.
It is, therefore, affected by multiple vulnerabilities.");
  #https://wordpress.org/news/2017/11/wordpress-4-9-1-security-and-maintenance-release/
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?383c32fd");
  script_set_attribute(attribute:"solution", value:
"Upgrade to WordPress version 4.9.1 or later.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:P/I:P/A:P");
  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:L/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2017-17091");
  script_set_attribute(attribute:"exploitability_ease", value:"No exploit is required");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/11/29");
  script_set_attribute(attribute:"patch_publication_date", value:"2017/11/29");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/12/04");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:wordpress:wordpress");
  script_set_attribute(attribute:"potential_vulnerability", value:"true");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"CGI abuses");

  script_copyright(english:"This script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("wordpress_detect.nasl");
  script_require_keys("www/PHP", "installed_sw/WordPress", "Settings/ParanoidReport");
  script_require_ports("Services/www", 80, 443);

  exit(0);
}

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

if (report_paranoia < 2) audit(AUDIT_PARANOID);

app = "WordPress";
port = get_http_port(default:80, php:TRUE);

app_info = vcf::get_app_info(app:app, port:port, webapp:TRUE);
vcf::check_granularity(app_info:app_info, sig_segments:2);

constraints = [
  { "min_version":"1.5", "fixed_version":"3.7.24", "fixed_display" : "3.7.24 / 4.9.1" },
  { "min_version":"3.8", "fixed_version":"3.8.24", "fixed_display" : "3.8.24 / 4.9.1" },
  { "min_version":"3.9", "fixed_version":"3.9.22", "fixed_display" : "3.9.22 / 4.9.1" },
  { "min_version":"4.0", "fixed_version":"4.0.21", "fixed_display" : "4.0.21 / 4.9.1" },
  { "min_version":"4.1", "fixed_version":"4.1.21", "fixed_display" : "4.1.21 / 4.9.1" },
  { "min_version":"4.2", "fixed_version":"4.2.18", "fixed_display" : "4.2.18 / 4.9.1" },
  { "min_version":"4.3", "fixed_version":"4.3.14", "fixed_display" : "4.3.14 / 4.9.1" },
  { "min_version":"4.4", "fixed_version":"4.4.13", "fixed_display" : "4.4.13 / 4.9.1" },
  { "min_version":"4.5", "fixed_version":"4.5.12", "fixed_display" : "4.5.12 / 4.9.1" },
  { "min_version":"4.6", "fixed_version":"4.6.9", "fixed_display" : "4.6.9 / 4.9.1" },
  { "min_version":"4.7", "fixed_version":"4.7.8", "fixed_display" : "4.7.8 / 4.9.1" },
  { "min_version":"4.8", "fixed_version":"4.8.4", "fixed_display" : "4.8.4 / 4.9.1" },
  { "min_version":"4.9", "fixed_version":"4.9.1", "fixed_display" : "4.9.1" }
];

vcf::check_version_and_report(
  app_info:app_info,
  constraints:constraints,
  severity:SECURITY_WARNING
);
  • NASL familyDebian Local Security Checks
    NASL idDEBIAN_DSA-4090.NASL
    descriptionSeveral vulnerabilities were discovered in Wordpress, a web blogging tool. They allowed remote attackers to perform SQL injections and various Cross-Side Scripting (XSS) and Server-Side Request Forgery (SSRF) attacks, as well as bypass some access restrictions.
    last seen2020-06-01
    modified2020-06-02
    plugin id106109
    published2018-01-18
    reporterThis script is Copyright (C) 2018 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/106109
    titleDebian DSA-4090-1 : wordpress - security update
    code
    #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from Debian Security Advisory DSA-4090. The text 
# itself is copyright (C) Software in the Public Interest, Inc.
#

include("compat.inc");

if (description)
{
  script_id(106109);
  script_version("3.6");
  script_cvs_date("Date: 2018/11/13 12:30:46");

  script_cve_id("CVE-2017-16510", "CVE-2017-17091", "CVE-2017-17092", "CVE-2017-17093", "CVE-2017-17094", "CVE-2017-9066");
  script_xref(name:"DSA", value:"4090");

  script_name(english:"Debian DSA-4090-1 : wordpress - security update");
  script_summary(english:"Checks dpkg output for the updated package");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Debian host is missing a security-related update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"Several vulnerabilities were discovered in Wordpress, a web blogging
tool. They allowed remote attackers to perform SQL injections and
various Cross-Side Scripting (XSS) and Server-Side Request Forgery
(SSRF) attacks, as well as bypass some access restrictions."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=862816"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=883314"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=880528"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://security-tracker.debian.org/tracker/source-package/wordpress"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://packages.debian.org/source/jessie/wordpress"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://packages.debian.org/source/stretch/wordpress"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://www.debian.org/security/2018/dsa-4090"
  );
  script_set_attribute(
    attribute:"solution", 
    value:
"Upgrade the wordpress packages.

For the oldstable distribution (jessie), these problems have been
fixed in version 4.1+dfsg-1+deb8u16.

For the stable distribution (stretch), these problems have been fixed
in version 4.7.5+dfsg-2+deb9u2."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");
  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_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:wordpress");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:8.0");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:9.0");

  script_set_attribute(attribute:"patch_publication_date", value:"2018/01/17");
  script_set_attribute(attribute:"plugin_publication_date", value:"2018/01/18");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2018 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"Debian Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/Debian/release", "Host/Debian/dpkg-l");

  exit(0);
}


include("audit.inc");
include("debian_package.inc");


if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (!get_kb_item("Host/Debian/release")) audit(AUDIT_OS_NOT, "Debian");
if (!get_kb_item("Host/Debian/dpkg-l")) audit(AUDIT_PACKAGE_LIST_MISSING);


flag = 0;
if (deb_check(release:"8.0", prefix:"wordpress", reference:"4.1+dfsg-1+deb8u16")) flag++;
if (deb_check(release:"8.0", prefix:"wordpress-l10n", reference:"4.1+dfsg-1+deb8u16")) flag++;
if (deb_check(release:"8.0", prefix:"wordpress-theme-twentyfifteen", reference:"4.1+dfsg-1+deb8u16")) flag++;
if (deb_check(release:"8.0", prefix:"wordpress-theme-twentyfourteen", reference:"4.1+dfsg-1+deb8u16")) flag++;
if (deb_check(release:"8.0", prefix:"wordpress-theme-twentythirteen", reference:"4.1+dfsg-1+deb8u16")) flag++;
if (deb_check(release:"9.0", prefix:"wordpress", reference:"4.7.5+dfsg-2+deb9u2")) flag++;
if (deb_check(release:"9.0", prefix:"wordpress-l10n", reference:"4.7.5+dfsg-2+deb9u2")) flag++;
if (deb_check(release:"9.0", prefix:"wordpress-theme-twentyfifteen", reference:"4.7.5+dfsg-2+deb9u2")) flag++;
if (deb_check(release:"9.0", prefix:"wordpress-theme-twentyseventeen", reference:"4.7.5+dfsg-2+deb9u2")) flag++;
if (deb_check(release:"9.0", prefix:"wordpress-theme-twentysixteen", reference:"4.7.5+dfsg-2+deb9u2")) flag++;

if (flag)
{
  if (report_verbosity > 0) security_hole(port:0, extra:deb_report_get());
  else security_hole(0);
  exit(0);
}
else audit(AUDIT_HOST_NOT, "affected");

References