GLSA-202208-06 : lxml: Multiple Vulnerabilities

#
# (C) Tenable, Inc.
#
# @NOAGENT@
#
# The descriptive text and package checks in this plugin were
# extracted from Gentoo Linux Security Advisory GLSA 202208-06.
#
# The advisory text is Copyright (C) 2001-2021 Gentoo Foundation, Inc.
# and licensed under the Creative Commons - Attribution / Share Alike
# license. See http://creativecommons.org/licenses/by-sa/3.0/
#

include('compat.inc');

if (description)
{
  script_id(163984);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/10/16");

  script_cve_id("CVE-2021-28957", "CVE-2021-43818", "CVE-2022-2309");

  script_name(english:"GLSA-202208-06 : lxml: Multiple Vulnerabilities");

  script_set_attribute(attribute:"synopsis", value:
"");
  script_set_attribute(attribute:"description", value:
"The remote host is affected by the vulnerability described in GLSA-202208-06 (lxml: Multiple Vulnerabilities)

  - An XSS vulnerability was discovered in python-lxml's clean module versions before 4.6.3. When disabling
    the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute
    allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS
    code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.
    (CVE-2021-28957)

  - lxml is a library for processing XML and HTML in the Python language. Prior to version 4.6.5, the HTML
    Cleaner in lxml.html lets certain crafted script content pass through, as well as script content in SVG
    files embedded using data URIs. Users that employ the HTML cleaner in a security relevant context should
    upgrade to lxml 4.6.5 to receive a patch. There are no known workarounds available. (CVE-2021-43818)

  - NULL Pointer Dereference allows attackers to cause a denial of service (or application crash). This only
    applies when lxml is used together with libxml2 2.9.10 through 2.9.14. libxml2 2.9.9 and earlier are not
    affected. It allows triggering crashes through forged input data, given a vulnerable code sequence in the
    application. The vulnerability is caused by the iterwalk function (also used by the canonicalize
    function). Such code shouldn't be in wide-spread use, given that parsing + iterwalk would usually be
    replaced with the more efficient iterparse function. However, an XML converter that serialises to C14N
    would also be vulnerable, for example, and there are legitimate use cases for this code sequence. If
    untrusted input is received (also remotely) and processed via iterwalk function, a crash can be triggered.
    (CVE-2022-2309)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version
number.");
  script_set_attribute(attribute:"see_also", value:"https://security.gentoo.org/glsa/202208-06");
  script_set_attribute(attribute:"see_also", value:"https://bugs.gentoo.org/show_bug.cgi?id=777579");
  script_set_attribute(attribute:"see_also", value:"https://bugs.gentoo.org/show_bug.cgi?id=829053");
  script_set_attribute(attribute:"see_also", value:"https://bugs.gentoo.org/show_bug.cgi?id=856598");
  script_set_attribute(attribute:"solution", value:
"All lxml users should upgrade to the latest version:

          # emerge --sync
          # emerge --ask --oneshot --verbose >=dev-python/lxml-4.9.1");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:P");
  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:R/S:C/C:L/I:L/A:L");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-43818");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2021/03/21");
  script_set_attribute(attribute:"patch_publication_date", value:"2022/08/10");
  script_set_attribute(attribute:"plugin_publication_date", value:"2022/08/10");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:gentoo:linux:lxml");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:gentoo:linux");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2022-2023 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/Gentoo/release", "Host/Gentoo/qpkg-list");

  exit(0);
}
include("qpkg.inc");

if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (!get_kb_item("Host/Gentoo/release")) audit(AUDIT_OS_NOT, "Gentoo");
if (!get_kb_item("Host/Gentoo/qpkg-list")) audit(AUDIT_PACKAGE_LIST_MISSING);

var flag = 0;

var packages = [
  {
    'name' : "dev-python/lxml",
    'unaffected' : make_list("ge 4.9.1"),
    'vulnerable' : make_list("lt 4.9.1")
  }
];

foreach package( packages ) {
  if (isnull(package['unaffected'])) package['unaffected'] = make_list();
  if (isnull(package['vulnerable'])) package['vulnerable'] = make_list();
  if (qpkg_check(package: package['name'] , unaffected: package['unaffected'], vulnerable: package['vulnerable'])) flag++;
}


if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : qpkg_report_get()
  );
  exit(0);
}
else
{
  var tested = qpkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "lxml");
}