Vulnerabilities > CVE-2017-9450 - Improper Privilege Management vulnerability in Amazon web Services Cloudformation Bootstrap

047910
CVSS 7.2 - HIGH
Attack vector
LOCAL
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
COMPLETE
Integrity impact
COMPLETE
Availability impact
COMPLETE
local
low complexity
amazon
CWE-269
nessus
NVD
Published: 2017-10-30
Updated: 2019-10-03

Summary

The Amazon Web Services (AWS) CloudFormation bootstrap tools package (aka aws-cfn-bootstrap) before 1.4-19.10 allows local users to execute arbitrary code with root privileges by leveraging the ability to create files in an unspecified directory.

Vulnerable Configurations

Part Description Count
Application
Amazon
1

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Restful Privilege Elevation
    Rest uses standard HTTP (Get, Put, Delete) style permissions methods, but these are not necessarily correlated generally with back end programs. Strict interpretation of HTTP get methods means that these HTTP Get services should not be used to delete information on the server, but there is no access control mechanism to back up this logic. This means that unless the services are properly ACL'd and the application's service implementation are following these guidelines then an HTTP request can easily execute a delete or update on the server side. The attacker identifies a HTTP Get URL such as http://victimsite/updateOrder, which calls out to a program to update orders on a database or other resource. The URL is not idempotent so the request can be submitted multiple times by the attacker, additionally, the attacker may be able to exploit the URL published as a Get method that actually performs updates (instead of merely retrieving data). This may result in malicious or inadvertent altering of data on the server.

Nessus

NASL familyAmazon Linux Local Security Checks
NASL idALA_ALAS-2017-861.NASL
descriptionA vulnerability was reported in the CloudFormation bootstrap tools that allows an attacker to execute arbitrary code as root if they have local access to the system and are able to create files in a specific directory (CVE-2017-9450 )
last seen2020-06-01
modified2020-06-02
plugin id101959
published2017-07-26
reporterThis script is Copyright (C) 2017-2018 Tenable Network Security, Inc.
sourcehttps://www.tenable.com/plugins/nessus/101959
titleAmazon Linux AMI : aws-cfn-bootstrap (ALAS-2017-861)
code
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux AMI Security Advisory ALAS-2017-861.
#

include("compat.inc");

if (description)
{
  script_id(101959);
  script_version("3.4");
  script_cvs_date("Date: 2018/04/18 15:09:36");

  script_cve_id("CVE-2017-9450");
  script_xref(name:"ALAS", value:"2017-861");

  script_name(english:"Amazon Linux AMI : aws-cfn-bootstrap (ALAS-2017-861)");
  script_summary(english:"Checks rpm output for the updated package");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Amazon Linux AMI host is missing a security update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"A vulnerability was reported in the CloudFormation bootstrap tools
that allows an attacker to execute arbitrary code as root if they have
local access to the system and are able to create files in a specific
directory (CVE-2017-9450 )"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://alas.aws.amazon.com/ALAS-2017-861.html"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Run 'yum update aws-cfn-bootstrap' to update your system."
  );
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:aws-cfn-bootstrap");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux");

  script_set_attribute(attribute:"patch_publication_date", value:"2017/07/25");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/07/26");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2017-2018 Tenable Network Security, Inc.");
  script_family(english:"Amazon Linux Local Security Checks");

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

  exit(0);
}


include("audit.inc");
include("global_settings.inc");
include("rpm.inc");


if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);

release = get_kb_item("Host/AmazonLinux/release");
if (isnull(release) || !strlen(release)) audit(AUDIT_OS_NOT, "Amazon Linux");
os_ver = pregmatch(pattern: "^AL(A|\d)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Amazon Linux");
os_ver = os_ver[1];
if (os_ver != "A")
{
  if (os_ver == 'A') os_ver = 'AMI';
  audit(AUDIT_OS_NOT, "Amazon Linux AMI", "Amazon Linux " + os_ver);
}

if (!get_kb_item("Host/AmazonLinux/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);


flag = 0;
if (rpm_check(release:"ALA", reference:"aws-cfn-bootstrap-1.4-19.10.amzn1")) flag++;

if (flag)
{
  if (report_verbosity > 0) security_hole(port:0, extra:rpm_report_get());
  else security_hole(0);
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "aws-cfn-bootstrap");
}

Packetstorm

data sourcehttps://packetstormsecurity.com/files/download/145177/awscfnbootstrap-exec.txt
idPACKETSTORM:145177
last seen2017-12-04
published2017-12-01
reporterHarry Sintonen
sourcehttps://packetstormsecurity.com/files/145177/aws-cfn-bootstrap-Local-Code-Execution.html
titleaws-cfn-bootstrap Local Code Execution

References