Vulnerabilities > CVE-2018-5520 - Incorrect Authorization vulnerability in F5 products

#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from F5 Networks BIG-IP Solution K02043709.
#
# The text description of this plugin is (C) F5 Networks.
#

include("compat.inc");

if (description)
{
  script_id(118616);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/03/09");

  script_cve_id("CVE-2018-5520");

  script_name(english:"F5 Networks BIG-IP : Appliance mode tmsh access vulnerability (K02043709)");
  script_summary(english:"Checks the BIG-IP version.");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote device is missing a vendor-supplied security patch."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"On a BIG-IP system configured in Appliance mode, the TMOS Shell (tmsh)
may allow an administrative user to use the dig utility to gain
unauthorized access to file system resources. (CVE-2018-5520)

Note : Appliance mode is designed to meet the needs of customers in
especially sensitive sectors by limiting the BIG-IP system
administrative access to match that of a typical network appliance and
not a multi-user UNIX device. When a BIG-IP system is configured in
Appliance mode, the Advanced Shell ( bash ) access to the file system
is restricted. For information about Appliance mode, refer to K12815:
Overview of Appliance mode.

Impact

This vulnerability allows unauthorized disclosure of information."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://support.f5.com/csp/article/K02043709"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://support.f5.com/csp/article/K12815"
  );
  script_set_attribute(
    attribute:"solution", 
    value:
"Upgrade to one of the non-vulnerable versions listed in the F5
Solution K02043709."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:S/C:P/I:N/A:N");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_access_policy_manager");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_advanced_firewall_manager");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_application_acceleration_manager");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_application_security_manager");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_application_visibility_and_reporting");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_global_traffic_manager");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_link_controller");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_local_traffic_manager");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_policy_enforcement_manager");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_webaccelerator");
  script_set_attribute(attribute:"cpe", value:"cpe:/h:f5:big-ip");

  script_set_attribute(attribute:"vuln_publication_date", value:"2018/05/02");
  script_set_attribute(attribute:"patch_publication_date", value:"2018/04/30");
  script_set_attribute(attribute:"plugin_publication_date", value:"2018/11/02");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2018-2020 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"F5 Networks Local Security Checks");

  script_dependencies("f5_bigip_detect.nbin");
  script_require_keys("Host/local_checks_enabled", "Host/BIG-IP/hotfix", "Host/BIG-IP/modules", "Host/BIG-IP/version");

  exit(0);
}


include("f5_func.inc");

if ( ! get_kb_item("Host/local_checks_enabled") ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
version = get_kb_item("Host/BIG-IP/version");
if ( ! version ) audit(AUDIT_OS_NOT, "F5 Networks BIG-IP");
if ( isnull(get_kb_item("Host/BIG-IP/hotfix")) ) audit(AUDIT_KB_MISSING, "Host/BIG-IP/hotfix");
if ( ! get_kb_item("Host/BIG-IP/modules") ) audit(AUDIT_KB_MISSING, "Host/BIG-IP/modules");

sol = "K02043709";
vmatrix = make_array();

# AFM
vmatrix["AFM"] = make_array();
vmatrix["AFM"]["affected"  ] = make_list("13.1.0","13.0.0","12.1.0-12.1.3","11.2.1-11.6.3");
vmatrix["AFM"]["unaffected"] = make_list("14.0.0","13.1.0.6","13.0.1","12.1.3.2");

# AM
vmatrix["AM"] = make_array();
vmatrix["AM"]["affected"  ] = make_list("13.1.0","13.0.0","12.1.0-12.1.3","11.2.1-11.6.3");
vmatrix["AM"]["unaffected"] = make_list("14.0.0","13.1.0.6","13.0.1","12.1.3.2");

# APM
vmatrix["APM"] = make_array();
vmatrix["APM"]["affected"  ] = make_list("13.1.0","13.0.0","12.1.0-12.1.3","11.2.1-11.6.3");
vmatrix["APM"]["unaffected"] = make_list("14.0.0","13.1.0.6","13.0.1","12.1.3.2");

# ASM
vmatrix["ASM"] = make_array();
vmatrix["ASM"]["affected"  ] = make_list("13.1.0","13.0.0","12.1.0-12.1.3","11.2.1-11.6.3");
vmatrix["ASM"]["unaffected"] = make_list("14.0.0","13.1.0.6","13.0.1","12.1.3.2");

# AVR
vmatrix["AVR"] = make_array();
vmatrix["AVR"]["affected"  ] = make_list("13.1.0","13.0.0","12.1.0-12.1.3","11.2.1-11.6.3");
vmatrix["AVR"]["unaffected"] = make_list("14.0.0","13.1.0.6","13.0.1","12.1.3.2");

# GTM
vmatrix["GTM"] = make_array();
vmatrix["GTM"]["affected"  ] = make_list("13.1.0","13.0.0","12.1.0-12.1.3","11.2.1-11.6.3");
vmatrix["GTM"]["unaffected"] = make_list("14.0.0","13.1.0.6","13.0.1","12.1.3.2");

# LC
vmatrix["LC"] = make_array();
vmatrix["LC"]["affected"  ] = make_list("13.1.0","13.0.0","12.1.0-12.1.3","11.2.1-11.6.3");
vmatrix["LC"]["unaffected"] = make_list("14.0.0","13.1.0.6","13.0.1","12.1.3.2");

# LTM
vmatrix["LTM"] = make_array();
vmatrix["LTM"]["affected"  ] = make_list("13.1.0","13.0.0","12.1.0-12.1.3","11.2.1-11.6.3");
vmatrix["LTM"]["unaffected"] = make_list("14.0.0","13.1.0.6","13.0.1","12.1.3.2");

# PEM
vmatrix["PEM"] = make_array();
vmatrix["PEM"]["affected"  ] = make_list("13.1.0","13.0.0","12.1.0-12.1.3","11.2.1-11.6.3");
vmatrix["PEM"]["unaffected"] = make_list("14.0.0","13.1.0.6","13.0.1","12.1.3.2");

# WAM
vmatrix["WAM"] = make_array();
vmatrix["WAM"]["affected"  ] = make_list("13.1.0","13.0.0","12.1.0-12.1.3","11.2.1-11.6.3");
vmatrix["WAM"]["unaffected"] = make_list("14.0.0","13.1.0.6","13.0.1","12.1.3.2");


if (bigip_is_affected(vmatrix:vmatrix, sol:sol))
{
  if (report_verbosity > 0) security_note(port:0, extra:bigip_report_get());
  else security_note(0);
  exit(0);
}
else
{
  tested = bigip_get_tested_modules();
  audit_extra = "For BIG-IP module(s) " + tested + ",";
  if (tested) audit(AUDIT_INST_VER_NOT_VULN, audit_extra, version);
  else audit(AUDIT_HOST_NOT, "running any of the affected modules");
}