Vulnerabilities > CVE-2019-12436 - NULL Pointer Dereference vulnerability in multiple products

047910
CVSS 6.5 - MEDIUM
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
LOW
Confidentiality impact
NONE
Integrity impact
NONE
Availability impact
HIGH
network
low complexity
samba
canonical
CWE-476
nessus

Summary

Samba 4.10.x before 4.10.5 has a NULL pointer dereference, leading to an AD DC LDAP server Denial of Service. This is related to an attacker using the paged search control. The attacker must have directory read access in order to attempt an exploit.

Common Weakness Enumeration (CWE)

Nessus

  • NASL familyFedora Local Security Checks
    NASL idFEDORA_2019-8015E5DC40.NASL
    descriptionFix vfs_fruit, vfs_glusterfs and smbspool ---- Update to Samba 4.10.5 Security fixes for CVE-2019-12435 and CVE-2019-12436 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 seen2020-06-01
    modified2020-06-02
    plugin id126518
    published2019-07-08
    reporterThis script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/126518
    titleFedora 30 : 2:samba (2019-8015e5dc40)
    code
    #
    # (C) Tenable Network Security, Inc.
    #
    # The descriptive text and package checks in this plugin were  
    # extracted from Fedora Security Advisory FEDORA-2019-8015e5dc40.
    #
    
    include("compat.inc");
    
    if (description)
    {
      script_id(126518);
      script_version("1.3");
      script_cvs_date("Date: 2020/01/08");
    
      script_cve_id("CVE-2019-12435", "CVE-2019-12436");
      script_xref(name:"FEDORA", value:"2019-8015e5dc40");
    
      script_name(english:"Fedora 30 : 2:samba (2019-8015e5dc40)");
      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:
    "Fix vfs_fruit, vfs_glusterfs and smbspool
    
    ----
    
    Update to Samba 4.10.5 Security fixes for CVE-2019-12435 and
    CVE-2019-12436
    
    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-2019-8015e5dc40"
      );
      script_set_attribute(
        attribute:"solution", 
        value:"Update the affected 2:samba package."
      );
      script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:N/I:N/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:N/I:N/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:2:samba");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:30");
    
      script_set_attribute(attribute:"vuln_publication_date", value:"2019/06/19");
      script_set_attribute(attribute:"patch_publication_date", value:"2019/07/06");
      script_set_attribute(attribute:"plugin_publication_date", value:"2019/07/08");
      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:"^30([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Fedora 30", "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:"FC30", reference:"samba-4.10.5-1.fc30", epoch:"2")) 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, "2:samba");
    }
    
  • NASL familyMisc.
    NASL idSAMBA_CVE-2019-12436.NASL
    descriptionThe version of Samba running on the remote host is 4.10.0 prior to 4.10.5. It is, therefore, potentially affected by a denial of service vulnerability in the AD DC LDAP server process. Note that Nessus has not tested for this issue but has instead relied only on the application
    last seen2020-06-01
    modified2020-06-02
    plugin id126308
    published2019-06-27
    reporterThis script is Copyright (C) 2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/126308
    title4.10.0 < 4.10.5 AC DC LDAP Server Denial of Service Vulnerability (CVE-2019-12436)
    code
    #
    # (C) Tenable Network Security, Inc.
    #
    
    include("compat.inc");
    
    if (description)
    {
      script_id(126308);
      script_version("1.2");
      script_cvs_date("Date: 2019/10/18 23:14:15");
    
      script_cve_id("CVE-2019-12436");
      script_bugtraq_id(108823);
      script_xref(name:"IAVA", value:"2019-A-0209");
    
      script_name(english:"4.10.0 < 4.10.5 AC DC LDAP Server Denial of Service Vulnerability (CVE-2019-12436)");
      script_summary(english:"Checks the version of Samba.");
    
      script_set_attribute(attribute:"synopsis", value:
    "The remote Samba server is potentially affected by a denial of service vulnerability.");
      script_set_attribute(attribute:"description", value:
    "The version of Samba running on the remote host is 4.10.0 prior to
    4.10.5. It is, therefore, potentially affected by a denial of service
    vulnerability in the AD DC LDAP server process. 
    
    Note that Nessus has not tested for this issue but has instead relied
    only on the application's self-reported version number.");
      script_set_attribute(attribute:"see_also", value:"https://www.samba.org/samba/security/CVE-2019-12436.html");
      script_set_attribute(attribute:"see_also", value:"https://www.samba.org/samba/history/samba-4.10.5.html");
      script_set_attribute(attribute:"solution", value:
    "Upgrade to Samba version 4.10.5 or later.");
      script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:N/I:N/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:N/I:N/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-2019-12436");
    
      script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
    
      script_set_attribute(attribute:"vuln_publication_date", value:"2019/06/19");
      script_set_attribute(attribute:"patch_publication_date", value:"2019/06/19");
      script_set_attribute(attribute:"plugin_publication_date", value:"2019/06/27");
    
      script_set_attribute(attribute:"potential_vulnerability", value:"true");
      script_set_attribute(attribute:"plugin_type", value:"remote");
      script_set_attribute(attribute:"cpe", value:"cpe:/a:samba:samba");
      script_set_attribute(attribute:"stig_severity", value:"I");
      script_end_attributes();
    
      script_category(ACT_GATHER_INFO);
      script_family(english:"Misc.");
    
      script_copyright(english:"This script is Copyright (C) 2019 and is owned by Tenable, Inc. or an Affiliate thereof.");
    
      script_dependencies("smb_nativelanman.nasl");
      script_require_keys("SMB/NativeLanManager", "SMB/samba", "Settings/ParanoidReport");
    
      exit(0);
    }
    
    include("audit.inc");
    include("global_settings.inc");
    include("misc_func.inc");
    include("vcf.inc");
    include("vcf_extras.inc");
    
    if (report_paranoia < 2) audit(AUDIT_PARANOID);
    
    app = vcf::samba::get_app_info();
    vcf::check_granularity(app_info:app, sig_segments:3);
    
    constraints = [
      {"min_version":"4.10.0rc0", "fixed_version":"4.10.5"}
    ];
    
    vcf::check_version_and_report(app_info:app, constraints:constraints, severity:SECURITY_WARNING, strict:FALSE);
    
  • NASL familyUbuntu Local Security Checks
    NASL idUBUNTU_USN-4018-1.NASL
    descriptionIt was discovered that Samba incorrectly handled certain RPC messages. A remote attacker could possibly use this issue to cause Samba to crash, resulting in a denial of service. (CVE-2019-12435) It was discovered that Samba incorrectly handled LDAP pages searches. A remote attacker could possibly use this issue to cause Samba to crash, resulting in a denial of service. (CVE-2019-12436). 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 id126064
    published2019-06-20
    reporterUbuntu Security Notice (C) 2019-2020 Canonical, Inc. / NASL script (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/126064
    titleUbuntu 19.04 : samba vulnerabilities (USN-4018-1)
    code
    #
    # (C) Tenable Network Security, Inc.
    #
    # The descriptive text and package checks in this plugin were
    # extracted from Ubuntu Security Notice USN-4018-1. 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(126064);
      script_version("1.3");
      script_cvs_date("Date: 2020/01/10");
    
      script_cve_id("CVE-2019-12435", "CVE-2019-12436");
      script_xref(name:"USN", value:"4018-1");
    
      script_name(english:"Ubuntu 19.04 : samba vulnerabilities (USN-4018-1)");
      script_summary(english:"Checks dpkg output for updated package.");
    
      script_set_attribute(
        attribute:"synopsis", 
        value:"The remote Ubuntu host is missing a security-related patch."
      );
      script_set_attribute(
        attribute:"description", 
        value:
    "It was discovered that Samba incorrectly handled certain RPC messages.
    A remote attacker could possibly use this issue to cause Samba to
    crash, resulting in a denial of service. (CVE-2019-12435)
    
    It was discovered that Samba incorrectly handled LDAP pages searches.
    A remote attacker could possibly use this issue to cause Samba to
    crash, resulting in a denial of service. (CVE-2019-12436).
    
    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/4018-1/"
      );
      script_set_attribute(attribute:"solution", value:"Update the affected samba package.");
      script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:N/I:N/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:N/I:N/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:canonical:ubuntu_linux:samba");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:19.04");
    
      script_set_attribute(attribute:"vuln_publication_date", value:"2019/06/19");
      script_set_attribute(attribute:"patch_publication_date", value:"2019/06/19");
      script_set_attribute(attribute:"plugin_publication_date", value:"2019/06/20");
      script_set_attribute(attribute:"generated_plugin", value:"current");
      script_end_attributes();
    
      script_category(ACT_GATHER_INFO);
      script_copyright(english:"Ubuntu Security Notice (C) 2019-2020 Canonical, Inc. / NASL script (C) 2019-2020 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:"^(19\.04)$", string:release)) audit(AUDIT_OS_NOT, "Ubuntu 19.04", "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:"19.04", pkgname:"samba", pkgver:"2:4.10.0+dfsg-0ubuntu2.2")) 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, "samba");
    }