Amazon Linux AMI : httpd24 (ALAS-2021-1543)

#%NASL_MIN_LEVEL 70300
##
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux AMI Security Advisory ALAS-2021-1543.
##

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

if (description)
{
  script_id(154188);
  script_version("1.16");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/01/18");

  script_cve_id(
    "CVE-2021-33193",
    "CVE-2021-34798",
    "CVE-2021-36160",
    "CVE-2021-39275",
    "CVE-2021-40438",
    "CVE-2021-41524",
    "CVE-2021-41773",
    "CVE-2021-42013"
  );
  script_xref(name:"ALAS", value:"2021-1543");
  script_xref(name:"IAVA", value:"2021-A-0440-S");
  script_xref(name:"IAVA", value:"2021-A-0451-S");
  script_xref(name:"CISA-KNOWN-EXPLOITED", value:"2021/11/17");
  script_xref(name:"CISA-KNOWN-EXPLOITED", value:"2021/12/15");
  script_xref(name:"CEA-ID", value:"CEA-2021-0046");

  script_name(english:"Amazon Linux AMI : httpd24 (ALAS-2021-1543)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Amazon Linux AMI host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The version of httpd24 installed on the remote host is prior to 2.4.51-1.94. It is, therefore, affected by multiple
vulnerabilities as referenced in the ALAS-2021-1543 advisory.

  - A crafted method sent through HTTP/2 will bypass validation and be forwarded by mod_proxy, which can lead
    to request splitting or cache poisoning. This issue affects Apache HTTP Server 2.4.17 to 2.4.48.
    (CVE-2021-33193)

  - Malformed requests may cause the server to dereference a NULL pointer. This issue affects Apache HTTP
    Server 2.4.48 and earlier. (CVE-2021-34798)

  - A carefully crafted request uri-path can cause mod_proxy_uwsgi to read above the allocated memory and
    crash (DoS). This issue affects Apache HTTP Server versions 2.4.30 to 2.4.48 (inclusive). (CVE-2021-36160)

  - ap_escape_quotes() may write beyond the end of a buffer when given malicious input. No included modules
    pass untrusted data to these functions, but third-party / external modules may. This issue affects Apache
    HTTP Server 2.4.48 and earlier. (CVE-2021-39275)

  - A crafted request uri-path can cause mod_proxy to forward the request to an origin server choosen by the
    remote user. This issue affects Apache HTTP Server 2.4.48 and earlier. (CVE-2021-40438)

  - While fuzzing the 2.4.49 httpd, a new null pointer dereference was detected during HTTP/2 request
    processing, allowing an external source to DoS the server. This requires a specially crafted request. The
    vulnerability was recently introduced in version 2.4.49. No exploit is known to the project.
    (CVE-2021-41524)

  - A flaw was found in a change made to path normalization in Apache HTTP Server 2.4.49. An attacker could
    use a path traversal attack to map URLs to files outside the directories configured by Alias-like
    directives. If files outside of these directories are not protected by the usual default configuration
    require all denied, these requests can succeed. If CGI scripts are also enabled for these aliased
    pathes, this could allow for remote code execution. This issue is known to be exploited in the wild. This
    issue only affects Apache 2.4.49 and not earlier versions. The fix in Apache HTTP Server 2.4.50 was found
    to be incomplete, see CVE-2021-42013. (CVE-2021-41773)

  - It was found that the fix for CVE-2021-41773 in Apache HTTP Server 2.4.50 was insufficient. An attacker
    could use a path traversal attack to map URLs to files outside the directories configured by Alias-like
    directives. If files outside of these directories are not protected by the usual default configuration
    require all denied, these requests can succeed. If CGI scripts are also enabled for these aliased
    pathes, this could allow for remote code execution. This issue only affects Apache 2.4.49 and Apache
    2.4.50 and not earlier versions. (CVE-2021-42013)

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://alas.aws.amazon.com/ALAS-2021-1543.html");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/cve/CVE-2021-33193");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/cve/CVE-2021-34798");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/cve/CVE-2021-36160");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/cve/CVE-2021-39275");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/cve/CVE-2021-40438");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/cve/CVE-2021-41524");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/cve/CVE-2021-41773");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/cve/CVE-2021-42013");
  script_set_attribute(attribute:"solution", value:
"Run 'yum update httpd24' to update your system.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:H/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:H/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-42013");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"d2_elliot_name", value:"Apache 2.4.50 RCE");
  script_set_attribute(attribute:"exploit_framework_d2_elliot", value:"true");
  script_set_attribute(attribute:"exploited_by_malware", value:"true");
  script_set_attribute(attribute:"metasploit_name", value:'Apache 2.4.49/2.4.50 Traversal RCE');
  script_set_attribute(attribute:"exploit_framework_metasploit", value:"true");
  script_set_attribute(attribute:"exploit_framework_canvas", value:"true");
  script_set_attribute(attribute:"canvas_package", value:"CANVAS");

  script_set_attribute(attribute:"vuln_publication_date", value:"2021/08/16");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/10/15");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/10/17");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:httpd24");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:httpd24-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:httpd24-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:httpd24-manual");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:httpd24-tools");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:mod24_ldap");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:mod24_md");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:mod24_proxy_html");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:mod24_session");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:mod24_ssl");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Amazon Linux 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/AmazonLinux/release", "Host/AmazonLinux/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);

var release = get_kb_item("Host/AmazonLinux/release");
if (isnull(release) || !strlen(release)) audit(AUDIT_OS_NOT, "Amazon Linux");
var os_ver = pregmatch(pattern: "^AL(A|\d)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Amazon Linux");
var os_ver = os_ver[1];
if (os_ver != "A")
{
  if (os_ver == 'A') os_ver = 'AMI';
  audit(AUDIT_OS_NOT, "Amazon Linux AMI", "Amazon Linux " + os_ver);
}

if (!get_kb_item("Host/AmazonLinux/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);

var pkgs = [
    {'reference':'httpd24-2.4.51-1.94.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'httpd24-2.4.51-1.94.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'httpd24-debuginfo-2.4.51-1.94.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'httpd24-debuginfo-2.4.51-1.94.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'httpd24-devel-2.4.51-1.94.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'httpd24-devel-2.4.51-1.94.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'httpd24-manual-2.4.51-1.94.amzn1', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'httpd24-tools-2.4.51-1.94.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'httpd24-tools-2.4.51-1.94.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'mod24_ldap-2.4.51-1.94.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'mod24_ldap-2.4.51-1.94.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'mod24_md-2.4.51-1.94.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'mod24_md-2.4.51-1.94.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'mod24_proxy_html-2.4.51-1.94.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'mod24_proxy_html-2.4.51-1.94.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'mod24_session-2.4.51-1.94.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'mod24_session-2.4.51-1.94.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'mod24_ssl-2.4.51-1.94.amzn1', 'cpu':'i686', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'mod24_ssl-2.4.51-1.94.amzn1', 'cpu':'x86_64', 'release':'ALA', 'rpm_spec_vers_cmp':TRUE}
];

var flag = 0;
foreach package_array ( pkgs ) {
  var reference = NULL;
  var release = NULL;
  var cpu = NULL;
  var el_string = NULL;
  var rpm_spec_vers_cmp = NULL;
  var allowmaj = NULL;
  if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
  if (!empty_or_null(package_array['release'])) release = package_array['release'];
  if (!empty_or_null(package_array['cpu'])) cpu = package_array['cpu'];
  if (!empty_or_null(package_array['el_string'])) el_string = package_array['el_string'];
  if (!empty_or_null(package_array['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = package_array['rpm_spec_vers_cmp'];
  if (!empty_or_null(package_array['allowmaj'])) allowmaj = package_array['allowmaj'];
  if (reference && release) {
    if (rpm_check(release:release, cpu:cpu, reference:reference, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj)) flag++;
  }
}

if (flag)
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_HOLE,
      extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  var tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "httpd24 / httpd24-debuginfo / httpd24-devel / etc");
}