EulerOS 2.0 SP5 : dnsmasq (EulerOS-SA-2021-1673)

#%NASL_MIN_LEVEL 70300
#
# (C) Tenable Network Security, Inc.
#

include('deprecated_nasl_level.inc');
include('compat.inc');

if (description)
{
  script_id(148050);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/01/08");

  script_cve_id(
    "CVE-2020-25681",
    "CVE-2020-25682",
    "CVE-2020-25683",
    "CVE-2020-25684",
    "CVE-2020-25685",
    "CVE-2020-25686",
    "CVE-2020-25687"
  );
  script_xref(name:"CEA-ID", value:"CEA-2021-0003");

  script_name(english:"EulerOS 2.0 SP5 : dnsmasq (EulerOS-SA-2021-1673)");

  script_set_attribute(attribute:"synopsis", value:
"The remote EulerOS host is missing multiple security updates.");
  script_set_attribute(attribute:"description", value:
"According to the versions of the dnsmasq packages installed, the
EulerOS installation on the remote host is affected by the following
vulnerabilities :

  - A flaw was found in dnsmasq before version 2.83. A
    heap-based buffer overflow was discovered in the way
    RRSets are sorted before validating with DNSSEC data.
    An attacker on the network, who can forge DNS replies
    such as that they are accepted as valid, could use this
    flaw to cause a buffer overflow with arbitrary data in
    a heap memory segment, possibly executing code on the
    machine. The highest threat from this vulnerability is
    to data confidentiality and integrity as well as system
    availability.(CVE-2020-25681)

  - A flaw was found in dnsmasq before 2.83. A buffer
    overflow vulnerability was discovered in the way
    dnsmasq extract names from DNS packets before
    validating them with DNSSEC data. An attacker on the
    network, who can create valid DNS replies, could use
    this flaw to cause an overflow with arbitrary data in a
    heap-allocated memory, possibly executing code on the
    machine. The flaw is in the rfc1035.c:extract_name()
    function, which writes data to the memory pointed by
    name assuming MAXDNAME*2 bytes are available in the
    buffer. However, in some code execution paths, it is
    possible extract_name() gets passed an offset from the
    base buffer, thus reducing, in practice, the number of
    available bytes that can be written in the buffer. The
    highest threat from this vulnerability is to data
    confidentiality and integrity as well as system
    availability.(CVE-2020-25682)

  - A flaw was found in dnsmasq before version 2.83. A
    heap-based buffer overflow was discovered in dnsmasq
    when DNSSEC is enabled and before it validates the
    received DNS entries. A remote attacker, who can create
    valid DNS replies, could use this flaw to cause an
    overflow in a heap-allocated memory. This flaw is
    caused by the lack of length checks in
    rfc1035.c:extract_name(), which could be abused to make
    the code execute memcpy() with a negative size in
    get_rdata() and cause a crash in dnsmasq, resulting in
    a denial of service. The highest threat from this
    vulnerability is to system
    availability.(CVE-2020-25683)

  - A flaw was found in dnsmasq before version 2.83. When
    getting a reply from a forwarded query, dnsmasq checks
    in the forward.c:reply_query() if the reply destination
    address/port is used by the pending forwarded queries.
    However, it does not use the address/port to retrieve
    the exact forwarded query, substantially reducing the
    number of attempts an attacker on the network would
    have to perform to forge a reply and get it accepted by
    dnsmasq. This issue contrasts with RFC5452, which
    specifies a query's attributes that all must be used to
    match a reply. This flaw allows an attacker to perform
    a DNS Cache Poisoning attack. If chained with
    CVE-2020-25685 or CVE-2020-25686, the attack complexity
    of a successful attack is reduced. The highest threat
    from this vulnerability is to data
    integrity.(CVE-2020-25684)

  - A flaw was found in dnsmasq before version 2.83. When
    getting a reply from a forwarded query, dnsmasq checks
    in forward.c:reply_query(), which is the forwarded
    query that matches the reply, by only using a weak hash
    of the query name. Due to the weak hash (CRC32 when
    dnsmasq is compiled without DNSSEC, SHA-1 when it is)
    this flaw allows an off-path attacker to find several
    different domains all having the same hash,
    substantially reducing the number of attempts they
    would have to perform to forge a reply and get it
    accepted by dnsmasq. This is in contrast with RFC5452,
    which specifies that the query name is one of the
    attributes of a query that must be used to match a
    reply. This flaw could be abused to perform a DNS Cache
    Poisoning attack. If chained with CVE-2020-25684 the
    attack complexity of a successful attack is reduced.
    The highest threat from this vulnerability is to data
    integrity.(CVE-2020-25685)

  - A flaw was found in dnsmasq before version 2.83. When
    receiving a query, dnsmasq does not check for an
    existing pending request for the same name and forwards
    a new request. By default, a maximum of 150 pending
    queries can be sent to upstream servers, so there can
    be at most 150 queries for the same name. This flaw
    allows an off-path attacker on the network to
    substantially reduce the number of attempts that it
    would have to perform to forge a reply and have it
    accepted by dnsmasq. This issue is mentioned in the
    'Birthday Attacks' section of RFC5452. If chained with
    CVE-2020-25684, the attack complexity of a successful
    attack is reduced. The highest threat from this
    vulnerability is to data integrity.(CVE-2020-25686)

  - A flaw was found in dnsmasq before version 2.83. A
    heap-based buffer overflow was discovered in dnsmasq
    when DNSSEC is enabled and before it validates the
    received DNS entries. This flaw allows a remote
    attacker, who can create valid DNS replies, to cause an
    overflow in a heap-allocated memory. This flaw is
    caused by the lack of length checks in
    rfc1035.c:extract_name(), which could be abused to make
    the code execute memcpy() with a negative size in
    sort_rrset() and cause a crash in dnsmasq, resulting in
    a denial of service. The highest threat from this
    vulnerability is to system
    availability.(CVE-2020-25687)

Note that Tenable Network Security has extracted the preceding
description block directly from the EulerOS security advisory. Tenable
has attempted to automatically clean and format it as much as possible
without introducing additional issues.");
  # https://developer.huaweicloud.com/ict/en/site-euleros/euleros/security-advisories/EulerOS-SA-2021-1673
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?bded9d9e");
  script_set_attribute(attribute:"solution", value:
"Update the affected dnsmasq packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:N/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-2020-25682");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"patch_publication_date", value:"2021/03/23");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/03/24");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:huawei:euleros:dnsmasq");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:huawei:euleros:dnsmasq-utils");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:huawei:euleros:2.0");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Huawei Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2021-2024 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/EulerOS/release", "Host/EulerOS/rpm-list", "Host/EulerOS/sp");
  script_exclude_keys("Host/EulerOS/uvp_version");

  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/EulerOS/release");
if (isnull(release) || release !~ "^EulerOS") audit(AUDIT_OS_NOT, "EulerOS");
if (release !~ "^EulerOS release 2\.0(\D|$)") audit(AUDIT_OS_NOT, "EulerOS 2.0");

sp = get_kb_item("Host/EulerOS/sp");
if (isnull(sp) || sp !~ "^(5)$") audit(AUDIT_OS_NOT, "EulerOS 2.0 SP5");

uvp = get_kb_item("Host/EulerOS/uvp_version");
if (!empty_or_null(uvp)) audit(AUDIT_OS_NOT, "EulerOS 2.0 SP5", "EulerOS UVP " + uvp);

if (!get_kb_item("Host/EulerOS/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$" && "aarch64" >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "EulerOS", cpu);
if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$") audit(AUDIT_ARCH_NOT, "i686 / x86_64", cpu);

flag = 0;

pkgs = ["dnsmasq-2.76-5.h7.eulerosv2r7",
        "dnsmasq-utils-2.76-5.h7.eulerosv2r7"];

foreach (pkg in pkgs)
  if (rpm_check(release:"EulerOS-2.0", sp:"5", reference:pkg)) flag++;

if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    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, "dnsmasq");
}