Cisco IOS Virtual PPP Interfaces Security Bypass

#
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(86950);
  script_version("1.9");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/12/09");

  script_cve_id("CVE-2015-6365");
  script_bugtraq_id(77583);
  script_xref(name:"CISCO-BUG-ID", value:"CSCur61303");
  script_xref(name:"CISCO-SA", value:"cisco-sa-20151112-ios1");

  script_name(english:"Cisco IOS Virtual PPP Interfaces Security Bypass");
  script_summary(english:"Checks the version of Cisco IOS");

  script_set_attribute(attribute:"synopsis", value:
"The remote device is missing a vendor-supplied security patch.");
  script_set_attribute(attribute:"description", value:
"The remote Cisco device is affected by a security bypass vulnerability
due to physical-interface ACLs superseding virtual PPP interface ACLs.
An authenticated, remote attacker connected to an authenticated PPP
session can exploit this to bypass intended network-traffic
restrictions.");
  # https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20151112-ios1
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?c59ed4b6");
  script_set_attribute(attribute:"solution", value:
"Upgrade to the relevant fixed version referenced in Cisco bug ID
CSCur61303.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:N/I:P/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2015-6365");
  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2015/11/13");
  script_set_attribute(attribute:"patch_publication_date", value:"2015/11/13");
  script_set_attribute(attribute:"plugin_publication_date", value:"2015/11/19");

  script_set_attribute(attribute:"potential_vulnerability", value:"true");
  script_set_attribute(attribute:"plugin_type", value:"combined");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:cisco:ios");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"CISCO");

  script_copyright(english:"This script is Copyright (C) 2015-2020 Tenable Network Security, Inc.");

  script_dependencies("cisco_ios_version.nasl");
  script_require_keys("Host/Cisco/IOS/Version", "Settings/ParanoidReport");

  exit(0);
}

include("audit.inc");
include("cisco_func.inc");

version = get_kb_item_or_exit('Host/Cisco/IOS/Version');
flag = 0;

if (report_paranoia < 2) audit(AUDIT_PARANOID);

if (version == "15.2(4)M") flag++;
if (version == "15.4(3)M")  flag++;

if (flag)
{
  if (report_verbosity > 0)
  {
    report =
    '\n  Cisco bug ID      : CSCur61303' +
    '\n  Installed release : ' + version +
    '\n';
    security_warning(port:0, extra:report);
  }
  else security_warning(port:0);
}
else audit(AUDIT_HOST_NOT, "affected");