RHEL 6 : libxml2 (Unpatched Vulnerability)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Red Hat Security Advisory libxml2. The text
# itself is copyright (C) Red Hat, Inc.
##

include('compat.inc');

if (description)
{
  script_id(195344);
  script_version("1.0");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/05/11");

  script_cve_id(
    "CVE-2016-3709",
    "CVE-2016-4483",
    "CVE-2016-4658",
    "CVE-2016-5131",
    "CVE-2016-9318",
    "CVE-2017-0663",
    "CVE-2017-5969",
    "CVE-2017-7375",
    "CVE-2017-8872",
    "CVE-2017-9047",
    "CVE-2017-9048",
    "CVE-2017-9049",
    "CVE-2017-9050",
    "CVE-2017-15412",
    "CVE-2017-16931",
    "CVE-2017-16932",
    "CVE-2018-14404",
    "CVE-2019-19956",
    "CVE-2020-7595",
    "CVE-2020-24977",
    "CVE-2021-3516",
    "CVE-2021-3517",
    "CVE-2021-3518",
    "CVE-2021-3537",
    "CVE-2021-3541",
    "CVE-2022-23308",
    "CVE-2022-29824",
    "CVE-2022-40303",
    "CVE-2022-40304",
    "CVE-2023-28484",
    "CVE-2023-29469",
    "CVE-2023-39615",
    "CVE-2023-45322",
    "CVE-2024-25062"
  );

  script_name(english:"RHEL 6 : libxml2 (Unpatched Vulnerability)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Red Hat 6 host is affected by multiple vulnerabilities that will not be patched.");
  script_set_attribute(attribute:"description", value:
"The remote Redhat Enterprise Linux 6 host has one or more packages installed that are affected by multiple
vulnerabilities that have been acknowledged by the vendor but will not be patched.

  - libxml2: Use after free via namespace node in XPointer ranges (CVE-2016-4658)

  - libxml2: Missing validation for external entities in xmlParsePEReference (CVE-2017-7375)

  - Possible cross-site scripting vulnerability in libxml after commit 960f0e2. (CVE-2016-3709)

  - The xmlBufAttrSerializeTxtContent function in xmlsave.c in libxml2 allows context-dependent attackers to
    cause a denial of service (out-of-bounds read and application crash) via a non-UTF-8 attribute value,
    related to serialization. NOTE: this vulnerability may be a duplicate of CVE-2016-3627. (CVE-2016-4483)

  - Use-after-free vulnerability in libxml2 through 2.9.4, as used in Google Chrome before 52.0.2743.82,
    allows remote attackers to cause a denial of service or possibly have unspecified other impact via vectors
    related to the XPointer range-to function. (CVE-2016-5131)

  - libxml2 2.9.4 and earlier, as used in XMLSec 1.2.23 and earlier and other products, does not offer a flag
    directly indicating that the current document may be read but other files may not be opened, which makes
    it easier for remote attackers to conduct XML External Entity (XXE) attacks via a crafted document.
    (CVE-2016-9318)

  - A remote code execution vulnerability in libxml2 could enable an attacker using a specially crafted file
    to execute arbitrary code within the context of an unprivileged process. This issue is rated as High due
    to the possibility of remote code execution in an application that uses this library. Product: Android.
    Versions: 4.4.4, 5.0.2, 5.1.1, 6.0, 6.0.1, 7.0, 7.1.1, 7.1.2. Android ID: A-37104170. (CVE-2017-0663)

  - Use after free in libxml2 before 2.9.5, as used in Google Chrome prior to 63.0.3239.84 and other products,
    allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page. (CVE-2017-15412)

  - parser.c in libxml2 before 2.9.5 mishandles parameter-entity references because the NEXTL macro calls the
    xmlParserHandlePEReference function in the case of a '%' character in a DTD name. (CVE-2017-16931)

  - parser.c in libxml2 before 2.9.5 does not prevent infinite recursion in parameter entities.
    (CVE-2017-16932)

  - libxml2 2.9.4, when used in recover mode, allows remote attackers to cause a denial of service (NULL
    pointer dereference) via a crafted XML document. NOTE: The maintainer states I would disagree of a CVE
    with the Recover parsing option which should only be used for manual recovery at least for XML parser.
    (CVE-2017-5969)

  - The htmlParseTryOrFinish function in HTMLparser.c in libxml2 2.9.4 allows attackers to cause a denial of
    service (buffer over-read) or information disclosure. (CVE-2017-8872)

  - A buffer overflow was discovered in libxml2 20904-GITv2.9.4-16-g0741801. The function
    xmlSnprintfElementContent in valid.c is supposed to recursively dump the element content definition into a
    char buffer 'buf' of size 'size'. The variable len is assigned strlen(buf). If the content->type is
    XML_ELEMENT_CONTENT_ELEMENT, then (i) the content->prefix is appended to buf (if it actually fits)
    whereupon (ii) content->name is written to the buffer. However, the check for whether the content->name
    actually fits also uses 'len' rather than the updated buffer length strlen(buf). This allows us to write
    about size many bytes beyond the allocated memory. This vulnerability causes programs that use libxml2,
    such as PHP, to crash. (CVE-2017-9047)

  - libxml2 20904-GITv2.9.4-16-g0741801 is vulnerable to a stack-based buffer overflow. The function
    xmlSnprintfElementContent in valid.c is supposed to recursively dump the element content definition into a
    char buffer 'buf' of size 'size'. At the end of the routine, the function may strcat two more characters
    without checking whether the current strlen(buf) + 2 < size. This vulnerability causes programs that use
    libxml2, such as PHP, to crash. (CVE-2017-9048)

  - libxml2 20904-GITv2.9.4-16-g0741801 is vulnerable to a heap-based buffer over-read in the
    xmlDictComputeFastKey function in dict.c. This vulnerability causes programs that use libxml2, such as
    PHP, to crash. This vulnerability exists because of an incomplete fix for libxml2 Bug 759398.
    (CVE-2017-9049)

  - libxml2 20904-GITv2.9.4-16-g0741801 is vulnerable to a heap-based buffer over-read in the xmlDictAddString
    function in dict.c. This vulnerability causes programs that use libxml2, such as PHP, to crash. This
    vulnerability exists because of an incomplete fix for CVE-2016-1839. (CVE-2017-9050)

  - A NULL pointer dereference vulnerability exists in the xpath.c:xmlXPathCompOpEval() function of libxml2
    through 2.9.8 when parsing an invalid XPath expression in the XPATH_OP_AND or XPATH_OP_OR case.
    Applications processing untrusted XSL format inputs with the use of the libxml2 library may be vulnerable
    to a denial of service attack due to a crash of the application. (CVE-2018-14404)

  - xmlParseBalancedChunkMemoryRecover in parser.c in libxml2 before 2.9.10 has a memory leak related to
    newDoc->oldNs. (CVE-2019-19956)

  - GNOME project libxml2 v2.9.10 has a global buffer over-read vulnerability in xmlEncodeEntitiesInternal at
    libxml2/entities.c. The issue has been fixed in commit 50f06b3e. (CVE-2020-24977)

  - xmlStringLenDecodeEntities in parser.c in libxml2 2.9.10 has an infinite loop in a certain end-of-file
    situation. (CVE-2020-7595)

  - There's a flaw in libxml2's xmllint in versions before 2.9.11. An attacker who is able to submit a crafted
    file to be processed by xmllint could trigger a use-after-free. The greatest impact of this flaw is to
    confidentiality, integrity, and availability. (CVE-2021-3516)

  - There is a flaw in the xml entity encoding functionality of libxml2 in versions before 2.9.11. An attacker
    who is able to supply a crafted file to be processed by an application linked with the affected
    functionality of libxml2 could trigger an out-of-bounds read. The most likely impact of this flaw is to
    application availability, with some potential impact to confidentiality and integrity if an attacker is
    able to use memory information to further exploit the application. (CVE-2021-3517)

  - There's a flaw in libxml2 in versions before 2.9.11. An attacker who is able to submit a crafted file to
    be processed by an application linked with libxml2 could trigger a use-after-free. The greatest impact
    from this flaw is to confidentiality, integrity, and availability. (CVE-2021-3518)

  - A vulnerability found in libxml2 in versions before 2.9.11 shows that it did not propagate errors while
    parsing XML mixed content, causing a NULL dereference. If an untrusted XML document was parsed in recovery
    mode and post-validated, the flaw could be used to crash the application. The highest threat from this
    vulnerability is to system availability. (CVE-2021-3537)

  - A flaw was found in libxml2. Exponential entity expansion attack its possible bypassing all existing
    protection mechanisms and leading to denial of service. (CVE-2021-3541)

  - valid.c in libxml2 before 2.9.13 has a use-after-free of ID and IDREF attributes. (CVE-2022-23308)

  - In libxml2 before 2.9.14, several buffer handling functions in buf.c (xmlBuf*) and tree.c (xmlBuffer*)
    don't check for integer overflows. This can result in out-of-bounds memory writes. Exploitation requires a
    victim to open a crafted, multi-gigabyte XML file. Other software using libxml2's buffer functions, for
    example libxslt through 1.1.35, is affected as well. (CVE-2022-29824)

  - An issue was discovered in libxml2 before 2.10.3. When parsing a multi-gigabyte XML document with the
    XML_PARSE_HUGE parser option enabled, several integer counters can overflow. This results in an attempt to
    access an array at a negative 2GB offset, typically leading to a segmentation fault. (CVE-2022-40303)

  - An issue was discovered in libxml2 before 2.10.3. Certain invalid XML entity definitions can corrupt a
    hash table key, potentially leading to subsequent logic errors. In one case, a double-free can be
    provoked. (CVE-2022-40304)

  - In libxml2 before 2.10.4, parsing of certain invalid XSD schemas can lead to a NULL pointer dereference
    and subsequently a segfault. This occurs in xmlSchemaFixupComplexType in xmlschemas.c. (CVE-2023-28484)

  - An issue was discovered in libxml2 before 2.10.4. When hashing empty dict strings in a crafted XML
    document, xmlDictComputeFastKey in dict.c can produce non-deterministic values, leading to various logic
    and memory errors, such as a double free. This behavior occurs because there is an attempt to use the
    first byte of an empty string, and any value is possible (not solely the '\0' value). (CVE-2023-29469)

  - Xmlsoft Libxml2 v2.11.0 was discovered to contain an out-of-bounds read via the xmlSAX2StartElement()
    function at /libxml2/SAX2.c. This vulnerability allows attackers to cause a Denial of Service (DoS) via
    supplying a crafted XML file. NOTE: the vendor's position is that the product does not support the legacy
    SAX1 interface with custom callbacks; there is a crash even without crafted input. (CVE-2023-39615)

  - libxml2 through 2.11.5 has a use-after-free that can only occur after a certain memory allocation fails.
    This occurs in xmlUnlinkNode in tree.c. NOTE: the vendor's position is I don't think these issues are
    critical enough to warrant a CVE ID ... because an attacker typically can't control when memory
    allocations fail. (CVE-2023-45322)

  - An issue was discovered in libxml2 before 2.11.7 and 2.12.x before 2.12.5. When using the XML Reader
    interface with DTD validation and XInclude expansion enabled, processing crafted XML documents can lead to
    an xmlValidatePopElement use-after-free. (CVE-2024-25062)

Note that Nessus has not tested for these issues but has instead relied on the package manager's report that the package
is installed.");
  script_set_attribute(attribute:"solution", value:
"The vendor has acknowledged the vulnerabilities but no solution has been provided. Refer to the vendor for remediation
guidance.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2016-4658");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2017-7375");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"vendor_unpatched", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2016/05/03");
  script_set_attribute(attribute:"plugin_publication_date", value:"2024/05/11");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:5");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:6");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:7");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:8");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:compat-expat1");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:libxml2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:mingw-libxml2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:mingw-virt-viewer");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

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

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

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

  exit(0);
}


include('rpm.inc');
include('rhel.inc');

if (!get_kb_item("global_settings/vendor_unpatched"))
exit(0, "Unpatched Vulnerabilities Detection not active.");

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_release = get_kb_item('Host/RedHat/release');
if (isnull(os_release) || 'Red Hat' >!< os_release) audit(AUDIT_OS_NOT, 'Red Hat');
var os_ver = pregmatch(pattern: "Red Hat Enterprise Linux.*release ([0-9]+(\.[0-9]+)?)", string:os_release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'Red Hat');
os_ver = os_ver[1];
if (!rhel_check_release(operator: 'ge', os_version: os_ver, rhel_version: '6')) audit(AUDIT_OS_NOT, 'Red Hat 6.x', 'Red Hat ' + os_ver);

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

var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('x86_64' >!< cpu && cpu !~ "^i[3-6]86$" && 's390' >!< cpu && 'aarch64' >!< cpu && 'ppc' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Red Hat', cpu);

var constraints = [
  {
    'pkgs': [
      {'reference':'compat-expat1', 'release':'6', 'rpm_spec_vers_cmp':TRUE, 'unpatched_pkg':'compat-expat1', 'cves':['CVE-2021-3516', 'CVE-2021-3517', 'CVE-2021-3518', 'CVE-2021-3541']},
      {'reference':'libxml2', 'release':'6', 'rpm_spec_vers_cmp':TRUE, 'unpatched_pkg':'libxml2'}
    ]
  }
];


var flag = 0;
foreach var constraint_array ( constraints ) {
  var repo_relative_urls = NULL;
  var enterprise_linux_flag = rhel_repo_urls_has_content_dist_rhel(repo_urls:repo_relative_urls);
  foreach var pkg ( constraint_array['pkgs'] ) {
    var unpatched_pkg = NULL;
    var _release = NULL;
    var sp = NULL;
    var el_string = NULL;
    var rpm_spec_vers_cmp = NULL;
    var exists_check = NULL;
    var cves = NULL;
    if (!empty_or_null(pkg['unpatched_pkg'])) unpatched_pkg = pkg['unpatched_pkg'];
    if (!empty_or_null(pkg['release'])) _release = 'RHEL' + pkg['release'];
    if (!empty_or_null(pkg['sp'])) sp = pkg['sp'];
    if (!empty_or_null(pkg['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = pkg['rpm_spec_vers_cmp'];
    if (!empty_or_null(pkg['exists_check'])) exists_check = pkg['exists_check'];
    if (!empty_or_null(pkg['cves'])) cves = pkg['cves'];
    if (unpatched_pkg &&
        _release &&
        (!exists_check || rpm_exists(release:_release, rpm:exists_check)) &&
        unpatched_package_exists(release:_release, package:unpatched_pkg, cves: cves)) flag++;
  }
}

if (flag)
{
  var extra = NULL;
  security_report_v4(
      port       : 0,
      severity   : SECURITY_HOLE,
      extra      : unpatched_packages_report()
  );
  exit(0);
}
else
{
  var tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'compat-expat1 / libxml2');
}