Amazon Linux AMI : ntp (ALAS-2014-462)

2014-12-22T00:00:00
ID ALA_ALAS-2014-462.NASL
Type nessus
Reporter Tenable
Modified 2018-04-18T00:00:00

Description

It was found that ntpd automatically generated weak keys for its internal use if no ntpdc request authentication key was specified in the ntp.conf configuration file. A remote attacker able to match the configured IP restrictions could guess the generated key, and possibly use it to send ntpdc query or configuration requests. (CVE-2014-9293)

It was found that ntp-keygen used a weak method for generating MD5 keys. This could possibly allow an attacker to guess generated MD5 keys that could then be used to spoof an NTP client or server. Note: it is recommended to regenerate any MD5 keys that had explicitly been generated with ntp-keygen; the default installation does not contain such keys). (CVE-2014-9294)

Multiple buffer overflow flaws were discovered in ntpd's crypto_recv(), ctl_putdata(), and configure() functions. A remote attacker could use either of these flaws to send a specially crafted request packet that could crash ntpd or, potentially, execute arbitrary code with the privileges of the ntp user. Note: the crypto_recv() flaw requires non default configurations to be active, while the ctl_putdata() flaw, by default, can only be exploited via local attackers, and the configure() flaw requires additional authentication to exploit. (CVE-2014-9295)

A missing return statement in the receive() function could potentially allow a remote attacker to bypass NTP's authentication mechanism. (CVE-2014-9296)

                                        
                                            #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux AMI Security Advisory ALAS-2014-462.
#

include("compat.inc");

if (description)
{
  script_id(80122);
  script_version("1.12");
  script_cvs_date("Date: 2018/04/18 15:09:35");

  script_cve_id("CVE-2014-9293", "CVE-2014-9294", "CVE-2014-9295", "CVE-2014-9296");
  script_xref(name:"ALAS", value:"2014-462");

  script_name(english:"Amazon Linux AMI : ntp (ALAS-2014-462)");
  script_summary(english:"Checks rpm output for the updated packages");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Amazon Linux AMI host is missing a security update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"It was found that ntpd automatically generated weak keys for its
internal use if no ntpdc request authentication key was specified in
the ntp.conf configuration file. A remote attacker able to match the
configured IP restrictions could guess the generated key, and possibly
use it to send ntpdc query or configuration requests. (CVE-2014-9293)

It was found that ntp-keygen used a weak method for generating MD5
keys. This could possibly allow an attacker to guess generated MD5
keys that could then be used to spoof an NTP client or server. Note:
it is recommended to regenerate any MD5 keys that had explicitly been
generated with ntp-keygen; the default installation does not contain
such keys). (CVE-2014-9294)

Multiple buffer overflow flaws were discovered in ntpd's
crypto_recv(), ctl_putdata(), and configure() functions. A remote
attacker could use either of these flaws to send a specially crafted
request packet that could crash ntpd or, potentially, execute
arbitrary code with the privileges of the ntp user. Note: the
crypto_recv() flaw requires non default configurations to be active,
while the ctl_putdata() flaw, by default, can only be exploited via
local attackers, and the configure() flaw requires additional
authentication to exploit. (CVE-2014-9295)

A missing return statement in the receive() function could potentially
allow a remote attacker to bypass NTP's authentication mechanism.
(CVE-2014-9296)"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://alas.aws.amazon.com/ALAS-2014-462.html"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Run 'yum update ntp' to update your system."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:ntp");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:ntp-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:ntp-doc");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:ntp-perl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:ntpdate");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux");

  script_set_attribute(attribute:"patch_publication_date", value:"2014/12/19");
  script_set_attribute(attribute:"plugin_publication_date", value:"2014/12/22");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2014-2018 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:"ntp-4.2.6p5-2.22.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"ntp-debuginfo-4.2.6p5-2.22.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"ntp-doc-4.2.6p5-2.22.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"ntp-perl-4.2.6p5-2.22.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"ntpdate-4.2.6p5-2.22.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, "ntp / ntp-debuginfo / ntp-doc / ntp-perl / ntpdate");
}