Vulnerabilities > CVE-2020-11869 - Integer Overflow or Wraparound vulnerability in Qemu

047910
CVSS 3.3 - LOW
Attack vector
LOCAL
Attack complexity
LOW
Privileges required
LOW
Confidentiality impact
NONE
Integrity impact
NONE
Availability impact
LOW
local
low complexity
qemu
CWE-190
nessus

Summary

An integer overflow was found in QEMU 4.0.1 through 4.2.0 in the way it implemented ATI VGA emulation. This flaw occurs in the ati_2d_blt() routine in hw/display/ati-2d.c while handling MMIO write operations through the ati_mm_write() callback. A malicious guest could abuse this flaw to crash the QEMU process, resulting in a denial of service.

Vulnerable Configurations

Part Description Count
Application
Qemu
18

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Forced Integer Overflow
    This attack forces an integer variable to go out of range. The integer variable is often used as an offset such as size of memory allocation or similarly. The attacker would typically control the value of such variable and try to get it out of range. For instance the integer in question is incremented past the maximum possible value, it may wrap to become a very small, or negative number, therefore providing a very incorrect value which can lead to unexpected behavior. At worst the attacker can execute arbitrary code.

Nessus

NASL familyUbuntu Local Security Checks
NASL idUBUNTU_USN-4372-1.NASL
descriptionIt was discovered that QEMU incorrectly handled bochs-display devices. A local attacker in a guest could use this to cause a denial of service or possibly execute arbitrary code in the host. This issue only affected Ubuntu 19.10. (CVE-2019-15034) It was discovered that QEMU incorrectly handled memory during certain VNC operations. A remote attacker could possibly use this issue to cause QEMU to consume resources, resulting in a denial of service. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 19.10. (CVE-2019-20382) It was discovered that QEMU incorrectly generated QEMU Pointer Authentication signatures on ARM. A local attacker could possibly use this issue to bypass PAuth. This issue only affected Ubuntu 19.10. (CVE-2020-10702) Ziming Zhang discovered that QEMU incorrectly handled ATI VGA emulation. A local attacker in a guest could use this issue to cause QEMU to crash, resulting in a denial of service. This issue only affected Ubuntu 20.04 LTS. (CVE-2020-11869) Aviv Sasson discovered that QEMU incorrectly handled Slirp networking. A remote attacker could use this issue to cause QEMU to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 19.10. (CVE-2020-1983). 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 seen2020-06-10
modified2020-05-22
plugin id136803
published2020-05-22
reporterUbuntu Security Notice (C) 2020 Canonical, Inc. / NASL script (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/136803
titleUbuntu 16.04 LTS / 18.04 LTS / 19.10 / 20.04 : qemu vulnerabilities (USN-4372-1)
code
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-4372-1. The text 
# itself is copyright (C) Canonical, Inc. See 
# <http://www.ubuntu.com/usn/>. Ubuntu(R) is a registered 
# trademark of Canonical, Inc.
#

include("compat.inc");

if (description)
{
  script_id(136803);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/07/24");

  script_cve_id(
    "CVE-2019-15034",
    "CVE-2019-20382",
    "CVE-2020-10702",
    "CVE-2020-11869",
    "CVE-2020-1983"
  );
  script_xref(name:"USN", value:"4372-1");
  script_xref(name:"IAVB", value:"2020-B-0026-S");

  script_name(english:"Ubuntu 16.04 LTS / 18.04 LTS / 19.10 / 20.04 : qemu vulnerabilities (USN-4372-1)");
  script_summary(english:"Checks dpkg output for updated packages.");

  script_set_attribute(
    attribute:"synopsis",
    value:
"The remote Ubuntu host is missing one or more security-related
patches."
  );
  script_set_attribute(
    attribute:"description",
    value:
"It was discovered that QEMU incorrectly handled bochs-display devices.
A local attacker in a guest could use this to cause a denial of
service or possibly execute arbitrary code in the host. This issue
only affected Ubuntu 19.10. (CVE-2019-15034)

It was discovered that QEMU incorrectly handled memory during certain
VNC operations. A remote attacker could possibly use this issue to
cause QEMU to consume resources, resulting in a denial of service.
This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and
Ubuntu 19.10. (CVE-2019-20382)

It was discovered that QEMU incorrectly generated QEMU Pointer
Authentication signatures on ARM. A local attacker could possibly use
this issue to bypass PAuth. This issue only affected Ubuntu 19.10.
(CVE-2020-10702)

Ziming Zhang discovered that QEMU incorrectly handled ATI VGA
emulation. A local attacker in a guest could use this issue to cause
QEMU to crash, resulting in a denial of service. This issue only
affected Ubuntu 20.04 LTS. (CVE-2020-11869)

Aviv Sasson discovered that QEMU incorrectly handled Slirp networking.
A remote attacker could use this issue to cause QEMU to crash,
resulting in a denial of service, or possibly execute arbitrary code.
This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and
Ubuntu 19.10. (CVE-2020-1983).

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."
  );
  script_set_attribute(attribute:"see_also", value:"https://usn.ubuntu.com/4372-1/");
  script_set_attribute(attribute:"solution", value:"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:L/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:H/PR:L/UI:N/S:U/C:L/I:L/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-2019-15034");
  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:canonical:ubuntu_linux:qemu");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:qemu-system");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:qemu-system-aarch64");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:qemu-system-arm");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:qemu-system-mips");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:qemu-system-ppc");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:qemu-system-s390x");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:qemu-system-sparc");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:qemu-system-x86");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.04");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:18.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:19.10");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:20.04");

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/03/05");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/05/21");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/05/22");
  script_set_attribute(attribute:"stig_severity", value:"II");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"Ubuntu Security Notice (C) 2020 Canonical, Inc. / NASL script (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"Ubuntu Local Security Checks");

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

  exit(0);
}


include("audit.inc");
include("ubuntu.inc");
include("misc_func.inc");

if ( ! get_kb_item("Host/local_checks_enabled") ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
release = get_kb_item("Host/Ubuntu/release");
if ( isnull(release) ) audit(AUDIT_OS_NOT, "Ubuntu");
release = chomp(release);
if (! preg(pattern:"^(16\.04|18\.04|19\.10|20\.04)$", string:release)) audit(AUDIT_OS_NOT, "Ubuntu 16.04 / 18.04 / 19.10 / 20.04", "Ubuntu " + release);
if ( ! get_kb_item("Host/Debian/dpkg-l") ) 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, "Ubuntu", cpu);

flag = 0;

if (ubuntu_check(osver:"16.04", pkgname:"qemu", pkgver:"1:2.5+dfsg-5ubuntu10.44")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"qemu-system", pkgver:"1:2.5+dfsg-5ubuntu10.44")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"qemu-system-aarch64", pkgver:"1:2.5+dfsg-5ubuntu10.44")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"qemu-system-arm", pkgver:"1:2.5+dfsg-5ubuntu10.44")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"qemu-system-mips", pkgver:"1:2.5+dfsg-5ubuntu10.44")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"qemu-system-ppc", pkgver:"1:2.5+dfsg-5ubuntu10.44")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"qemu-system-s390x", pkgver:"1:2.5+dfsg-5ubuntu10.44")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"qemu-system-sparc", pkgver:"1:2.5+dfsg-5ubuntu10.44")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"qemu-system-x86", pkgver:"1:2.5+dfsg-5ubuntu10.44")) flag++;
if (ubuntu_check(osver:"18.04", pkgname:"qemu", pkgver:"1:2.11+dfsg-1ubuntu7.26")) flag++;
if (ubuntu_check(osver:"18.04", pkgname:"qemu-system", pkgver:"1:2.11+dfsg-1ubuntu7.26")) flag++;
if (ubuntu_check(osver:"18.04", pkgname:"qemu-system-arm", pkgver:"1:2.11+dfsg-1ubuntu7.26")) flag++;
if (ubuntu_check(osver:"18.04", pkgname:"qemu-system-mips", pkgver:"1:2.11+dfsg-1ubuntu7.26")) flag++;
if (ubuntu_check(osver:"18.04", pkgname:"qemu-system-ppc", pkgver:"1:2.11+dfsg-1ubuntu7.26")) flag++;
if (ubuntu_check(osver:"18.04", pkgname:"qemu-system-s390x", pkgver:"1:2.11+dfsg-1ubuntu7.26")) flag++;
if (ubuntu_check(osver:"18.04", pkgname:"qemu-system-sparc", pkgver:"1:2.11+dfsg-1ubuntu7.26")) flag++;
if (ubuntu_check(osver:"18.04", pkgname:"qemu-system-x86", pkgver:"1:2.11+dfsg-1ubuntu7.26")) flag++;
if (ubuntu_check(osver:"19.10", pkgname:"qemu", pkgver:"1:4.0+dfsg-0ubuntu9.6")) flag++;
if (ubuntu_check(osver:"19.10", pkgname:"qemu-system", pkgver:"1:4.0+dfsg-0ubuntu9.6")) flag++;
if (ubuntu_check(osver:"19.10", pkgname:"qemu-system-arm", pkgver:"1:4.0+dfsg-0ubuntu9.6")) flag++;
if (ubuntu_check(osver:"19.10", pkgname:"qemu-system-mips", pkgver:"1:4.0+dfsg-0ubuntu9.6")) flag++;
if (ubuntu_check(osver:"19.10", pkgname:"qemu-system-ppc", pkgver:"1:4.0+dfsg-0ubuntu9.6")) flag++;
if (ubuntu_check(osver:"19.10", pkgname:"qemu-system-s390x", pkgver:"1:4.0+dfsg-0ubuntu9.6")) flag++;
if (ubuntu_check(osver:"19.10", pkgname:"qemu-system-sparc", pkgver:"1:4.0+dfsg-0ubuntu9.6")) flag++;
if (ubuntu_check(osver:"19.10", pkgname:"qemu-system-x86", pkgver:"1:4.0+dfsg-0ubuntu9.6")) flag++;
if (ubuntu_check(osver:"20.04", pkgname:"qemu", pkgver:"1:4.2-3ubuntu6.1")) flag++;
if (ubuntu_check(osver:"20.04", pkgname:"qemu-system", pkgver:"1:4.2-3ubuntu6.1")) flag++;
if (ubuntu_check(osver:"20.04", pkgname:"qemu-system-arm", pkgver:"1:4.2-3ubuntu6.1")) flag++;
if (ubuntu_check(osver:"20.04", pkgname:"qemu-system-mips", pkgver:"1:4.2-3ubuntu6.1")) flag++;
if (ubuntu_check(osver:"20.04", pkgname:"qemu-system-ppc", pkgver:"1:4.2-3ubuntu6.1")) flag++;
if (ubuntu_check(osver:"20.04", pkgname:"qemu-system-s390x", pkgver:"1:4.2-3ubuntu6.1")) flag++;
if (ubuntu_check(osver:"20.04", pkgname:"qemu-system-sparc", pkgver:"1:4.2-3ubuntu6.1")) flag++;
if (ubuntu_check(osver:"20.04", pkgname:"qemu-system-x86", pkgver:"1:4.2-3ubuntu6.1")) flag++;

if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : ubuntu_report_get()
  );
  exit(0);
}
else
{
  tested = ubuntu_pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "qemu / qemu-system / qemu-system-aarch64 / qemu-system-arm / etc");
}