Oracle Linux 8 : openssh (ELSA-2019-3702)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Oracle Linux Security Advisory ELSA-2019-3702.
##

include('compat.inc');

if (description)
{
  script_id(180726);
  script_version("1.0");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/09/07");

  script_cve_id("CVE-2018-20685", "CVE-2019-6109", "CVE-2019-6111");

  script_name(english:"Oracle Linux 8 : openssh (ELSA-2019-3702)");

  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 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the
ELSA-2019-3702 advisory.

  - In OpenSSH 7.9, scp.c in the scp client allows remote SSH servers to bypass intended access restrictions
    via the filename of . or an empty filename. The impact is modifying the permissions of the target
    directory on the client side. (CVE-2018-20685)

  - An issue was discovered in OpenSSH 7.9. Due to missing character encoding in the progress display, a
    malicious server (or Man-in-The-Middle attacker) can employ crafted object names to manipulate the client
    output, e.g., by using ANSI control codes to hide additional files being transferred. This affects
    refresh_progress_meter() in progressmeter.c. (CVE-2019-6109)

  - An issue was discovered in OpenSSH 7.9. Due to the scp implementation being derived from 1983 rcp, the
    server chooses which files/directories are sent to the client. However, the scp client only performs
    cursory validation of the object name returned (only directory traversal attacks are prevented). A
    malicious scp server (or Man-in-The-Middle attacker) can overwrite arbitrary files in the scp client
    target directory. If recursive operation (-r) is performed, the server can manipulate subdirectories as
    well (for example, to overwrite the .ssh/authorized_keys file). (CVE-2019-6111)

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-2019-3702.html");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:N/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:H/PR:N/UI:R/S:U/C:H/I:H/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2019-6111");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2019-6109");

  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:"2019/01/10");
  script_set_attribute(attribute:"patch_publication_date", value:"2019/11/14");
  script_set_attribute(attribute:"plugin_publication_date", value:"2023/09/07");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:oracle:linux:8");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:openssh");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:openssh-askpass");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:openssh-cavs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:openssh-clients");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:openssh-keycat");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:openssh-ldap");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:openssh-server");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:pam_ssh_agent_auth");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  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:"^8([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, 'Oracle Linux 8', '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':'openssh-8.0p1-3.el8', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-askpass-8.0p1-3.el8', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-cavs-8.0p1-3.el8', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-clients-8.0p1-3.el8', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-keycat-8.0p1-3.el8', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-ldap-8.0p1-3.el8', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-server-8.0p1-3.el8', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'pam_ssh_agent_auth-0.10.3-7.3.el8', 'cpu':'aarch64', 'release':'8', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'openssh-8.0p1-3.el8', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-askpass-8.0p1-3.el8', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-cavs-8.0p1-3.el8', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-clients-8.0p1-3.el8', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-keycat-8.0p1-3.el8', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-ldap-8.0p1-3.el8', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'openssh-server-8.0p1-3.el8', 'cpu':'x86_64', 'release':'8', 'rpm_spec_vers_cmp':TRUE, 'allowmaj':TRUE},
    {'reference':'pam_ssh_agent_auth-0.10.3-7.3.el8', 'cpu':'x86_64', 'release':'8', '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_WARNING,
      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, 'openssh / openssh-askpass / openssh-cavs / etc');
}