Vulnerabilities > CVE-2016-9818 - Improper Access Control vulnerability in XEN 4.7.0/4.7.1

047910
CVSS 4.9 - MEDIUM
Attack vector
LOCAL
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
NONE
Availability impact
COMPLETE
local
low complexity
xen
CWE-284
nessus

Summary

Xen through 4.7.x allows local ARM guest OS users to cause a denial of service (host crash) via vectors involving an asynchronous abort while at HYP.

Vulnerable Configurations

Part Description Count
OS
Xen
2

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 familyFedora Local Security Checks
    NASL idFEDORA_2016-CC2916DCF4.NASL
    descriptionARM guests may induce host asynchronous abort [XSA-201, CVE-2016-9815, CVE-2016-9816, CVE-2016-9817, CVE-2016-9818] (#1399747) qemu: Divide by zero vulnerability in cirrus_do_copy (#1399055) [CVE-2016-9921, CVE-2016-9922] Qemu: 9pfs: memory leakage via proxy/handle callbacks (#1402278) qemu ioport array overflow [XSA-199, CVE-2016-9637] 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
    modified2016-12-20
    plugin id96025
    published2016-12-20
    reporterThis script is Copyright (C) 2016-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/96025
    titleFedora 23 : xen (2016-cc2916dcf4)
    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-2016-cc2916dcf4.
    #
    
    include("compat.inc");
    
    if (description)
    {
      script_id(96025);
      script_version("3.7");
      script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/04");
    
      script_cve_id("CVE-2016-9637", "CVE-2016-9815", "CVE-2016-9816", "CVE-2016-9817", "CVE-2016-9818", "CVE-2016-9913", "CVE-2016-9921", "CVE-2016-9922");
      script_xref(name:"FEDORA", value:"2016-cc2916dcf4");
    
      script_name(english:"Fedora 23 : xen (2016-cc2916dcf4)");
      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:
    "ARM guests may induce host asynchronous abort [XSA-201, CVE-2016-9815,
    CVE-2016-9816, CVE-2016-9817, CVE-2016-9818] (#1399747) qemu: Divide
    by zero vulnerability in cirrus_do_copy (#1399055) [CVE-2016-9921,
    CVE-2016-9922] Qemu: 9pfs: memory leakage via proxy/handle callbacks
    (#1402278) qemu ioport array overflow [XSA-199, CVE-2016-9637]
    
    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-2016-cc2916dcf4"
      );
      script_set_attribute(attribute:"solution", value:"Update the affected xen package.");
      script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:N/I:N/A:C");
      script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:H/PR:H/UI:N/S:C/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:xen");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:23");
    
      script_set_attribute(attribute:"vuln_publication_date", value:"2016/12/23");
      script_set_attribute(attribute:"patch_publication_date", value:"2016/12/18");
      script_set_attribute(attribute:"plugin_publication_date", value:"2016/12/20");
      script_set_attribute(attribute:"generated_plugin", value:"current");
      script_end_attributes();
    
      script_category(ACT_GATHER_INFO);
      script_copyright(english:"This script is Copyright (C) 2016-2020 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:"^23([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Fedora 23", "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:"FC23", reference:"xen-4.5.5-5.fc23")) 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, "xen");
    }
    
  • NASL familyGentoo Local Security Checks
    NASL idGENTOO_GLSA-201612-56.NASL
    descriptionThe remote host is affected by the vulnerability described in GLSA-201612-56 (Xen: Multiple vulnerabilities) Multiple vulnerabilities have been discovered in Xen. Please review the CVE identifiers referenced below for details. Impact : A local attacker could possibly execute arbitrary code with the privileges of the process, could gain privileges on the host system, cause a Denial of Service condition, or obtain sensitive information. Workaround : There is no known workaround at this time.
    last seen2020-06-01
    modified2020-06-02
    plugin id96231
    published2017-01-03
    reporterThis script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/96231
    titleGLSA-201612-56 : Xen: Multiple vulnerabilities
  • NASL familyFedora Local Security Checks
    NASL idFEDORA_2016-BCBAE0781F.NASL
    descriptionx86 CMPXCHG8B emulation fails to ignore operand size override [XSA-200, CVE-2016-9932] (#1404262) ---- ARM guests may induce host asynchronous abort [XSA-201, CVE-2016-9815, CVE-2016-9816, CVE-2016-9817, CVE-2016-9818] (#1399747) qemu: Divide by zero vulnerability in cirrus_do_copy (#1399055) [CVE-2016-9921, CVE-2016-9922] Qemu: 9pfs: memory leakage via proxy/handle callbacks (#1402278) qemu ioport array overflow [XSA-199, CVE-2016-9637] 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
    modified2016-12-27
    plugin id96113
    published2016-12-27
    reporterThis script is Copyright (C) 2016-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/96113
    titleFedora 24 : xen (2016-bcbae0781f)