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nessusThis script is Copyright (C) 2023 and is owned by Tenable, Inc. or an Affiliate thereof.ORACLELINUX_ELSA-2023-6679.NASL
HistoryNov 16, 2023 - 12:00 a.m.

Oracle Linux 9 : curl (ELSA-2023-6679)

2023-11-1600:00:00
This script is Copyright (C) 2023 and is owned by Tenable, Inc. or an Affiliate thereof.
www.tenable.com
25
oracle linux 9
curl package
vulnerabilities
elsa-2023-6679
input validation
telnet protocol
authentication bypass
libcurl
communication security
path traversal
nessus scanner

8.4 High

AI Score

Confidence

High

The remote Oracle Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2023-6679 advisory.

  • A vulnerability in input validation exists in curl <8.0 during communication using the TELNET protocol may allow an attacker to pass on maliciously crafted user name and telnet options during server negotiation.
    The lack of proper input scrubbing allows an attacker to send content or perform option negotiation without the application’s intent. This vulnerability could be exploited if an application allows user input, thereby enabling attackers to execute arbitrary code on the system. (CVE-2023-27533)

  • An authentication bypass vulnerability exists libcurl <8.0.0 in the connection reuse feature which can reuse previously established connections with incorrect user permissions due to a failure to check for changes in the CURLOPT_GSSAPI_DELEGATION option. This vulnerability affects krb5/kerberos/negotiate/GSSAPI transfers and could potentially result in unauthorized access to sensitive information. The safest option is to not reuse connections if the CURLOPT_GSSAPI_DELEGATION option has been changed. (CVE-2023-27536)

  • An authentication bypass vulnerability exists in libcurl prior to v8.0.0 where it reuses a previously established SSH connection despite the fact that an SSH option was modified, which should have prevented reuse. libcurl maintains a pool of previously used connections to reuse them for subsequent transfers if the configurations match. However, two SSH settings were omitted from the configuration check, allowing them to match easily, potentially leading to the reuse of an inappropriate connection. (CVE-2023-27538)

  • A path traversal vulnerability exists in curl <8.0.0 SFTP implementation causes the tilde (~) character to be wrongly replaced when used as a prefix in the first path element, in addition to its intended use as the first element to indicate a path relative to the user’s home directory. Attackers can exploit this flaw to bypass filtering or execute arbitrary code by crafting a path like /~2/foo while accessing a server with a specific user. (CVE-2023-27534)

Note that Nessus has not tested for these issues but has instead relied only on the application’s self-reported version number.

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Oracle Linux Security Advisory ELSA-2023-6679.
##

include('compat.inc');

if (description)
{
  script_id(185857);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/12/08");

  script_cve_id(
    "CVE-2023-27533",
    "CVE-2023-27534",
    "CVE-2023-27536",
    "CVE-2023-27538"
  );
  script_xref(name:"IAVA", value:"2023-A-0153-S");
  script_xref(name:"IAVA", value:"2023-A-0531-S");

  script_name(english:"Oracle Linux 9 : curl (ELSA-2023-6679)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Oracle Linux host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Oracle Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the
ELSA-2023-6679 advisory.

  - A vulnerability in input validation exists in curl <8.0 during communication using the TELNET protocol may
    allow an attacker to pass on maliciously crafted user name and telnet options during server negotiation.
    The lack of proper input scrubbing allows an attacker to send content or perform option negotiation
    without the application's intent. This vulnerability could be exploited if an application allows user
    input, thereby enabling attackers to execute arbitrary code on the system. (CVE-2023-27533)

  - An authentication bypass vulnerability exists libcurl <8.0.0 in the connection reuse feature which can
    reuse previously established connections with incorrect user permissions due to a failure to check for
    changes in the CURLOPT_GSSAPI_DELEGATION option. This vulnerability affects krb5/kerberos/negotiate/GSSAPI
    transfers and could potentially result in unauthorized access to sensitive information. The safest option
    is to not reuse connections if the CURLOPT_GSSAPI_DELEGATION option has been changed. (CVE-2023-27536)

  - An authentication bypass vulnerability exists in libcurl prior to v8.0.0 where it reuses a previously
    established SSH connection despite the fact that an SSH option was modified, which should have prevented
    reuse. libcurl maintains a pool of previously used connections to reuse them for subsequent transfers if
    the configurations match. However, two SSH settings were omitted from the configuration check, allowing
    them to match easily, potentially leading to the reuse of an inappropriate connection. (CVE-2023-27538)

  - A path traversal vulnerability exists in curl <8.0.0 SFTP implementation causes the tilde (~) character to
    be wrongly replaced when used as a prefix in the first path element, in addition to its intended use as
    the first element to indicate a path relative to the user's home directory. Attackers can exploit this
    flaw to bypass filtering or execute arbitrary code by crafting a path like /~2/foo while accessing a
    server with a specific user. (CVE-2023-27534)

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://linux.oracle.com/errata/ELSA-2023-6679.html");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  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:L/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-2023-27533");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2023-27534");

  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:"2023/03/20");
  script_set_attribute(attribute:"patch_publication_date", value:"2023/11/11");
  script_set_attribute(attribute:"plugin_publication_date", value:"2023/11/16");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:oracle:linux:9:3:appstream_base");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:oracle:linux:9::appstream");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:oracle:linux:9");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:oracle:linux:9:3:baseos_base");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:oracle:linux:9::baseos_latest");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:curl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:curl-minimal");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:libcurl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:libcurl-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:libcurl-minimal");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

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

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

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

  exit(0);
}


include('rpm.inc');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (!get_kb_item('Host/OracleLinux')) audit(AUDIT_OS_NOT, 'Oracle Linux');
var os_release = get_kb_item("Host/RedHat/release");
if (isnull(os_release) || !pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux)", string:os_release)) audit(AUDIT_OS_NOT, 'Oracle Linux');
var os_ver = pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux) .*release ([0-9]+(\.[0-9]+)?)", string:os_release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'Oracle Linux');
os_ver = os_ver[1];
if (! preg(pattern:"^9([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, 'Oracle Linux 9', 'Oracle Linux ' + 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$" && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Oracle Linux', cpu);

var pkgs = [
    {'reference':'curl-7.76.1-26.el9', 'cpu':'aarch64', 'release':'9', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'curl-minimal-7.76.1-26.el9', 'cpu':'aarch64', 'release':'9', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libcurl-7.76.1-26.el9', 'cpu':'aarch64', 'release':'9', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libcurl-devel-7.76.1-26.el9', 'cpu':'aarch64', 'release':'9', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libcurl-minimal-7.76.1-26.el9', 'cpu':'aarch64', 'release':'9', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libcurl-7.76.1-26.el9', 'cpu':'i686', 'release':'9', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libcurl-devel-7.76.1-26.el9', 'cpu':'i686', 'release':'9', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libcurl-minimal-7.76.1-26.el9', 'cpu':'i686', 'release':'9', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'curl-7.76.1-26.el9', 'cpu':'x86_64', 'release':'9', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'curl-minimal-7.76.1-26.el9', 'cpu':'x86_64', 'release':'9', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libcurl-7.76.1-26.el9', 'cpu':'x86_64', 'release':'9', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libcurl-devel-7.76.1-26.el9', 'cpu':'x86_64', 'release':'9', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libcurl-minimal-7.76.1-26.el9', 'cpu':'x86_64', 'release':'9', 'rpm_spec_vers_cmp':TRUE}
];

var flag = 0;
foreach var package_array ( pkgs ) {
  var reference = NULL;
  var _release = NULL;
  var sp = NULL;
  var _cpu = NULL;
  var el_string = NULL;
  var rpm_spec_vers_cmp = NULL;
  var epoch = NULL;
  var allowmaj = NULL;
  var exists_check = NULL;
  if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
  if (!empty_or_null(package_array['release'])) _release = 'EL' + package_array['release'];
  if (!empty_or_null(package_array['sp'])) sp = package_array['sp'];
  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['epoch'])) epoch = package_array['epoch'];
  if (!empty_or_null(package_array['allowmaj'])) allowmaj = package_array['allowmaj'];
  if (!empty_or_null(package_array['exists_check'])) exists_check = package_array['exists_check'];
  if (reference && _release) {
    if (exists_check) {
        if (rpm_exists(release:_release, rpm:exists_check) && rpm_check(release:_release, sp:sp, cpu:cpu, reference:reference, epoch:epoch, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj)) flag++;
    } else {
        if (rpm_check(release:_release, sp:sp, cpu:_cpu, reference:reference, epoch:epoch, 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, 'curl / curl-minimal / libcurl / etc');
}
VendorProductVersionCPE
oraclelinux9cpe:/a:oracle:linux:9:3:appstream_base
oraclelinux9cpe:/a:oracle:linux:9::appstream
oraclelinux9cpe:/o:oracle:linux:9
oraclelinux9cpe:/o:oracle:linux:9:3:baseos_base
oraclelinux9cpe:/o:oracle:linux:9::baseos_latest
oraclelinuxcurlp-cpe:/a:oracle:linux:curl
oraclelinuxcurl-minimalp-cpe:/a:oracle:linux:curl-minimal
oraclelinuxlibcurlp-cpe:/a:oracle:linux:libcurl
oraclelinuxlibcurl-develp-cpe:/a:oracle:linux:libcurl-devel
oraclelinuxlibcurl-minimalp-cpe:/a:oracle:linux:libcurl-minimal