Vulnerabilities > CVE-2018-9918 - Uncontrolled Recursion vulnerability in multiple products

047910
CVSS 7.8 - HIGH
Attack vector
LOCAL
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
HIGH
Integrity impact
HIGH
Availability impact
HIGH
local
low complexity
qpdf-project
canonical
CWE-674
nessus
NVD
Published: 2018-04-10
Updated: 2019-10-03

Summary

libqpdf.a in QPDF through 8.0.2 mishandles certain "expected dictionary key but found non-name object" cases, allowing remote attackers to cause a denial of service (stack exhaustion), related to the QPDFObjectHandle and QPDF_Dictionary classes, because nesting in direct objects is not restricted.

Vulnerable Configurations

Part Description Count
Application
Qpdf_Project
50
OS
Canonical
3

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • XML Nested Payloads
    Applications often need to transform data in and out of the XML format by using an XML parser. It may be possible for an attacker to inject data that may have an adverse effect on the XML parser when it is being processed. By nesting XML data and causing this data to be continuously self-referential, an attacker can cause the XML parser to consume more resources while processing, causing excessive memory consumption and CPU utilization. An attacker's goal is to leverage parser failure to his or her advantage. In most cases this type of an attack will result in a denial of service due to an application becoming unstable, freezing, or crash. However it may be possible to cause a crash resulting in arbitrary code execution, leading to a jump from the data plane to the control plane [R.230.1].
  • XML Oversized Payloads
    Applications often need to transform data in and out of the XML format by using an XML parser. It may be possible for an attacker to inject data that may have an adverse effect on the XML parser when it is being processed. By supplying oversized payloads in input vectors that will be processed by the XML parser, an attacker can cause the XML parser to consume more resources while processing, causing excessive memory consumption and CPU utilization, and potentially cause execution of arbitrary code. An attacker's goal is to leverage parser failure to his or her advantage. In many cases this type of an attack will result in a denial of service due to an application becoming unstable, freezing, or crash. However it is possible to cause a crash resulting in arbitrary code execution, leading to a jump from the data plane to the control plane [R.231.1].
  • 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.
  • XML Parser Attack
    Applications often need to transform data in and out of the XML format by using an XML parser. It may be possible for an attacker to inject data that may have an adverse effect on the XML parser when it is being processed. These adverse effects may include the parser crashing, consuming too much of a resource, executing too slowly, executing code supplied by an attacker, allowing usage of unintended system functionality, etc. An attacker's goal is to leverage parser failure to his or her advantage. In some cases it may be possible to jump from the data plane to the control plane via bad data being passed to an XML parser. [R.99.1]

Nessus

  • NASL familyFedora Local Security Checks
    NASL idFEDORA_2018-F2E1C09437.NASL
    descriptionRebase to qpdf-7.1.1 because of security fixes for CVE-2018-9918, CVE-2017-11627, CVE-2017-12595. Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen2020-06-05
    modified2018-05-01
    plugin id109436
    published2018-05-01
    reporterThis script is Copyright (C) 2018-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/109436
    titleFedora 27 : cups-filters / qpdf (2018-f2e1c09437)
    code
    #%NASL_MIN_LEVEL 80502
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from Fedora Security Advisory FEDORA-2018-f2e1c09437.
#

include("compat.inc");

if (description)
{
  script_id(109436);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/04");

  script_cve_id("CVE-2017-11627", "CVE-2017-12595", "CVE-2018-9918");
  script_xref(name:"FEDORA", value:"2018-f2e1c09437");

  script_name(english:"Fedora 27 : cups-filters / qpdf (2018-f2e1c09437)");
  script_summary(english:"Checks rpm output for the updated packages.");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Fedora host is missing one or more security updates."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"Rebase to qpdf-7.1.1 because of security fixes for CVE-2018-9918,
CVE-2017-11627, CVE-2017-12595.

Note that Tenable Network Security has extracted the preceding
description block directly from the Fedora update system website.
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://bodhi.fedoraproject.org/updates/FEDORA-2018-f2e1c09437"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Update the affected cups-filters and / or qpdf packages."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:P");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:N/UI:R/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:fedoraproject:fedora:cups-filters");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fedoraproject:fedora:qpdf");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:27");

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/07/25");
  script_set_attribute(attribute:"patch_publication_date", value:"2018/04/30");
  script_set_attribute(attribute:"plugin_publication_date", value:"2018/05/01");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2018-2020 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"Fedora Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/RedHat/release", "Host/RedHat/rpm-list");

  exit(0);
}


include("audit.inc");
include("global_settings.inc");
include("rpm.inc");


if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
release = get_kb_item("Host/RedHat/release");
if (isnull(release) || "Fedora" >!< release) audit(AUDIT_OS_NOT, "Fedora");
os_ver = pregmatch(pattern: "Fedora.*release ([0-9]+)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Fedora");
os_ver = os_ver[1];
if (! preg(pattern:"^27([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Fedora 27", "Fedora " + os_ver);

if (!get_kb_item("Host/RedHat/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);


cpu = get_kb_item("Host/cpu");
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Fedora", cpu);


flag = 0;
if (rpm_check(release:"FC27", reference:"cups-filters-1.16.1-5.fc27")) flag++;
if (rpm_check(release:"FC27", reference:"qpdf-7.1.1-5.fc27")) flag++;


if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "cups-filters / qpdf");
}
  • NASL familyFedora Local Security Checks
    NASL idFEDORA_2018-B4EF545DB5.NASL
    descriptionSecurity fix for CVE-2018-9918 Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen2020-06-05
    modified2019-01-03
    plugin id120724
    published2019-01-03
    reporterThis script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/120724
    titleFedora 28 : qpdf (2018-b4ef545db5)
    code
    #%NASL_MIN_LEVEL 80502
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from Fedora Security Advisory FEDORA-2018-b4ef545db5.
#

include("compat.inc");

if (description)
{
  script_id(120724);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/04");

  script_cve_id("CVE-2018-9918");
  script_xref(name:"FEDORA", value:"2018-b4ef545db5");

  script_name(english:"Fedora 28 : qpdf (2018-b4ef545db5)");
  script_summary(english:"Checks rpm output for the updated package.");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Fedora host is missing a security update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"Security fix for CVE-2018-9918

Note that Tenable Network Security has extracted the preceding
description block directly from the Fedora update system website.
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://bodhi.fedoraproject.org/updates/FEDORA-2018-b4ef545db5"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected qpdf package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/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:L/AC:L/PR:N/UI:R/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:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fedoraproject:fedora:qpdf");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:28");

  script_set_attribute(attribute:"vuln_publication_date", value:"2018/04/10");
  script_set_attribute(attribute:"patch_publication_date", value:"2018/04/27");
  script_set_attribute(attribute:"plugin_publication_date", value:"2019/01/03");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"Fedora Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/RedHat/release", "Host/RedHat/rpm-list");

  exit(0);
}


include("audit.inc");
include("global_settings.inc");
include("rpm.inc");


if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
release = get_kb_item("Host/RedHat/release");
if (isnull(release) || "Fedora" >!< release) audit(AUDIT_OS_NOT, "Fedora");
os_ver = pregmatch(pattern: "Fedora.*release ([0-9]+)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Fedora");
os_ver = os_ver[1];
if (! preg(pattern:"^28([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Fedora 28", "Fedora " + os_ver);

if (!get_kb_item("Host/RedHat/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);


cpu = get_kb_item("Host/cpu");
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Fedora", cpu);


flag = 0;
if (rpm_check(release:"FC28", reference:"qpdf-7.1.1-5.fc28")) flag++;


if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "qpdf");
}
  • NASL familyUbuntu Local Security Checks
    NASL idUBUNTU_USN-3638-1.NASL
    descriptionIt was discovered that QPDF incorrectly handled certain malformed files. A remote attacker could use this issue to cause QPDF to crash, resulting in a denial of service, or possibly execute arbitrary code. Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen2020-06-01
    modified2020-06-02
    plugin id109600
    published2018-05-08
    reporterUbuntu Security Notice (C) 2018-2019 Canonical, Inc. / NASL script (C) 2018-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/109600
    titleUbuntu 14.04 LTS / 16.04 LTS / 17.10 : qpdf vulnerabilities (USN-3638-1)

References