Ubuntu 14.04 LTS / 16.04 LTS / 16.10 / 17.04 : shadow regression (USN-3276-2)

2017-05-17T00:00:00
ID UBUNTU_USN-3276-2.NASL
Type nessus
Reporter Ubuntu Security Notice (C) 2017-2019 Canonical, Inc. / NASL script (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
Modified 2020-07-02T00:00:00

Description

USN-3276-1 intended to fix a vulnerability in su. The solution introduced a regression in su signal handling. This update modifies the security fix. We apologize for the inconvenience.

Sebastian Krahmer discovered integer overflows in shadow utilities. A local attacker could possibly cause them to crash or potentially gain privileges via crafted input. (CVE-2016-6252)

Tobias Stockmann discovered a race condition in su. A local attacker could cause su to send SIGKILL to other processes with root privileges. (CVE-2017-2616).

Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

                                        
                                            #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-3276-2. The text 
# itself is copyright (C) Canonical, Inc. See 
# <http://www.ubuntu.com/usn/>. Ubuntu(R) is a registered 
# trademark of Canonical, Inc.
#

include("compat.inc");

if (description)
{
  script_id(100248);
  script_version("3.7");
  script_cvs_date("Date: 2019/09/18 12:31:47");

  script_cve_id("CVE-2016-6252", "CVE-2017-2616");
  script_xref(name:"USN", value:"3276-2");

  script_name(english:"Ubuntu 14.04 LTS / 16.04 LTS / 16.10 / 17.04 : shadow regression (USN-3276-2)");
  script_summary(english:"Checks dpkg output for updated packages.");

  script_set_attribute(
    attribute:"synopsis", 
    value:
"The remote Ubuntu host is missing one or more security-related
patches."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"USN-3276-1 intended to fix a vulnerability in su. The solution
introduced a regression in su signal handling. This update modifies
the security fix. We apologize for the inconvenience.

Sebastian Krahmer discovered integer overflows in shadow utilities. A
local attacker could possibly cause them to crash or potentially gain
privileges via crafted input. (CVE-2016-6252)

Tobias Stockmann discovered a race condition in su. A local
attacker could cause su to send SIGKILL to other processes
with root privileges. (CVE-2017-2616).

Note that Tenable Network Security has extracted the preceding
description block directly from the Ubuntu security advisory. Tenable
has attempted to automatically clean and format it as much as possible
without introducing additional issues."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://usn.ubuntu.com/3276-2/"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Update the affected login, passwd and / or uidmap packages."
  );
  script_set_cvss_base_vector("CVSS2#AV:L/AC:M/Au:N/C:N/I:N/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:L/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:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:login");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:passwd");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:uidmap");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:14.04");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.04");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.10");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:17.04");

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/02/17");
  script_set_attribute(attribute:"patch_publication_date", value:"2017/05/16");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/05/17");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"Ubuntu Security Notice (C) 2017-2019 Canonical, Inc. / NASL script (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"Ubuntu Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/cpu", "Host/Ubuntu", "Host/Ubuntu/release", "Host/Debian/dpkg-l");

  exit(0);
}


include("audit.inc");
include("ubuntu.inc");
include("misc_func.inc");

if ( ! get_kb_item("Host/local_checks_enabled") ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
release = get_kb_item("Host/Ubuntu/release");
if ( isnull(release) ) audit(AUDIT_OS_NOT, "Ubuntu");
release = chomp(release);
if (! preg(pattern:"^(14\.04|16\.04|16\.10|17\.04)$", string:release)) audit(AUDIT_OS_NOT, "Ubuntu 14.04 / 16.04 / 16.10 / 17.04", "Ubuntu " + release);
if ( ! get_kb_item("Host/Debian/dpkg-l") ) audit(AUDIT_PACKAGE_LIST_MISSING);

cpu = get_kb_item("Host/cpu");
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Ubuntu", cpu);

flag = 0;

if (ubuntu_check(osver:"14.04", pkgname:"login", pkgver:"1:4.1.5.1-1ubuntu9.5")) flag++;
if (ubuntu_check(osver:"14.04", pkgname:"passwd", pkgver:"1:4.1.5.1-1ubuntu9.5")) flag++;
if (ubuntu_check(osver:"14.04", pkgname:"uidmap", pkgver:"1:4.1.5.1-1ubuntu9.5")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"login", pkgver:"1:4.2-3.1ubuntu5.3")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"passwd", pkgver:"1:4.2-3.1ubuntu5.3")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"uidmap", pkgver:"1:4.2-3.1ubuntu5.3")) flag++;
if (ubuntu_check(osver:"16.10", pkgname:"login", pkgver:"1:4.2-3.2ubuntu1.16.10.2")) flag++;
if (ubuntu_check(osver:"16.10", pkgname:"passwd", pkgver:"1:4.2-3.2ubuntu1.16.10.2")) flag++;
if (ubuntu_check(osver:"16.10", pkgname:"uidmap", pkgver:"1:4.2-3.2ubuntu1.16.10.2")) flag++;
if (ubuntu_check(osver:"17.04", pkgname:"login", pkgver:"1:4.2-3.2ubuntu1.17.04.2")) flag++;
if (ubuntu_check(osver:"17.04", pkgname:"passwd", pkgver:"1:4.2-3.2ubuntu1.17.04.2")) flag++;
if (ubuntu_check(osver:"17.04", pkgname:"uidmap", pkgver:"1:4.2-3.2ubuntu1.17.04.2")) flag++;

if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : ubuntu_report_get()
  );
  exit(0);
}
else
{
  tested = ubuntu_pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "login / passwd / uidmap");
}