Cisco NX-OS Software Bash Bypass Guest Shell (CVE-2019-1730)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(501278);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/07/26");

  script_cve_id("CVE-2019-1730");

  script_name(english:"Cisco NX-OS Software Bash Bypass Guest Shell (CVE-2019-1730)");

  script_set_attribute(attribute:"synopsis", value:
"The remote OT asset is affected by a vulnerability.");
  script_set_attribute(attribute:"description", value:
"A vulnerability in the Bash shell implementation for Cisco NX-OS
Software could allow an authenticated, local attacker to bypass the
limited command set of the restricted Guest Shell and execute commands
at the privilege level of a network-admin user outside of the Guest
Shell. The attacker must authenticate with valid administrator device
credentials. The vulnerability is due to the incorrect implementation
of a CLI command that allows a Bash command to be incorrectly invoked
on the Guest Shell CLI. An attacker could exploit this vulnerability
by authenticating to the device and entering a crafted command at the
Guest Shell prompt. A successful exploit could allow the attacker to
issue commands that should be restricted by a Guest Shell account.

This plugin only works with Tenable.ot.
Please visit https://www.tenable.com/products/tenable-ot for more information.");
  script_set_attribute(attribute:"see_also", value:"http://www.securityfocus.com/bid/108397");
  # https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190515-nxos-bash-bypass
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?d0c1d1a8");
  script_set_attribute(attribute:"solution", value:
"Refer to the vendor advisory.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2019-1730");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");

  script_set_attribute(attribute:"vuln_publication_date", value:"2019/05/15");
  script_set_attribute(attribute:"patch_publication_date", value:"2019/05/15");
  script_set_attribute(attribute:"plugin_publication_date", value:"2023/07/25");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:cisco:nx-os:7");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:cisco:nx-os:8");
  script_set_attribute(attribute:"generated_plugin", value:"former");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Tenable.ot");

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

  script_dependencies("tenable_ot_api_integration.nasl");
  script_require_keys("Tenable.ot/Cisco");

  exit(0);
}


include('tenable_ot_cve_funcs.inc');

get_kb_item_or_exit('Tenable.ot/Cisco');

var asset = tenable_ot::assets::get(vendor:'Cisco');

var vuln_cpes = {
    "cpe:/o:cisco:nx-os:7.0%283%29i4%289%29" :
        {"versionEndExcluding" : "7.0%283%29i4%289%29", "versionStartIncluding" : "7.0%283%29i4", "family" : "NXOS"},
    "cpe:/o:cisco:nx-os:7.0%283%29i7%284%29" :
        {"versionEndExcluding" : "7.0%283%29i7%284%29", "versionStartIncluding" : "7.0%283%29i7", "family" : "NXOS"},
    "cpe:/o:cisco:nx-os:8.3%281%29" :
        {"versionEndExcluding" : "8.3%281%29", "versionStartIncluding" : "8.1", "family" : "NXOS"},
    "cpe:/o:cisco:nx-os:7.0%283%29f3%285%29" :
        {"versionEndExcluding" : "7.0%283%29f3%285%29", "versionStartIncluding" : "7.0%283%29", "family" : "NXOS"}
};

tenable_ot::cve::compare_and_report(asset:asset, cpes:vuln_cpes, severity:SECURITY_HOLE);