Oracle Linux 6 : openssh (ELSA-2017-2563)

2017-09-01T00:00:00
ID ORACLELINUX_ELSA-2017-2563.NASL
Type nessus
Reporter This script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
Modified 2020-06-02T00:00:00

Description

From Red Hat Security Advisory 2017:2563 :

An update for openssh is now available for Red Hat Enterprise Linux 6.

Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server.

Security Fix(es) :

  • A covert timing channel flaw was found in the way OpenSSH handled authentication of non-existent users. A remote unauthenticated attacker could possibly use this flaw to determine valid user names by measuring the timing of server responses. (CVE-2016-6210)

                                        
                                            #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Red Hat Security Advisory RHSA-2017:2563 and 
# Oracle Linux Security Advisory ELSA-2017-2563 respectively.
#

include("compat.inc");

if (description)
{
  script_id(102904);
  script_version("3.5");
  script_cvs_date("Date: 2019/09/27 13:00:38");

  script_cve_id("CVE-2016-6210");
  script_xref(name:"RHSA", value:"2017:2563");

  script_name(english:"Oracle Linux 6 : openssh (ELSA-2017-2563)");
  script_summary(english:"Checks rpm output for the updated packages");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Oracle Linux host is missing one or more security updates."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"From Red Hat Security Advisory 2017:2563 :

An update for openssh is now available for Red Hat Enterprise Linux 6.

Red Hat Product Security has rated this update as having a security
impact of Moderate. A Common Vulnerability Scoring System (CVSS) base
score, which gives a detailed severity rating, is available for each
vulnerability from the CVE link(s) in the References section.

OpenSSH is an SSH protocol implementation supported by a number of
Linux, UNIX, and similar operating systems. It includes the core files
necessary for both the OpenSSH client and server.

Security Fix(es) :

* A covert timing channel flaw was found in the way OpenSSH handled
authentication of non-existent users. A remote unauthenticated
attacker could possibly use this flaw to determine valid user names by
measuring the timing of server responses. (CVE-2016-6210)"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://oss.oracle.com/pipermail/el-errata/2017-August/007169.html"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Update the affected openssh packages."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:P/I:N/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:openssh");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:openssh-askpass");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:openssh-clients");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:openssh-ldap");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:openssh-server");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:pam_ssh_agent_auth");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:oracle:linux:6");

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/02/13");
  script_set_attribute(attribute:"patch_publication_date", value:"2017/08/31");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/09/01");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"Oracle Linux Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/OracleLinux", "Host/RedHat/release", "Host/RedHat/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);
if (!get_kb_item("Host/OracleLinux")) audit(AUDIT_OS_NOT, "Oracle Linux");
release = get_kb_item("Host/RedHat/release");
if (isnull(release) || !pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux)", string:release)) audit(AUDIT_OS_NOT, "Oracle Linux");
os_ver = pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux) .*release ([0-9]+(\.[0-9]+)?)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Oracle Linux");
os_ver = os_ver[1];
if (! preg(pattern:"^6([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Oracle Linux 6", "Oracle Linux " + os_ver);

if (!get_kb_item("Host/RedHat/rpm-list")) 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, "Oracle Linux", cpu);

flag = 0;
if (rpm_check(release:"EL6", reference:"openssh-5.3p1-123.el6_9")) flag++;
if (rpm_check(release:"EL6", reference:"openssh-askpass-5.3p1-123.el6_9")) flag++;
if (rpm_check(release:"EL6", reference:"openssh-clients-5.3p1-123.el6_9")) flag++;
if (rpm_check(release:"EL6", reference:"openssh-ldap-5.3p1-123.el6_9")) flag++;
if (rpm_check(release:"EL6", reference:"openssh-server-5.3p1-123.el6_9")) flag++;
if (rpm_check(release:"EL6", reference:"pam_ssh_agent_auth-0.9.3-123.el6_9")) flag++;


if (flag)
{
  if (report_verbosity > 0) security_warning(port:0, extra:rpm_report_get());
  else security_warning(0);
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "openssh / openssh-askpass / openssh-clients / openssh-ldap / etc");
}