It was discovered that the OpenSSH sshd daemon fetched PAM environment settings before running the login program. In configurations with UseLogin=yes and the pam_env PAM module configured to read user environment settings, a local user could use this flaw to execute arbitrary code as root.
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux AMI Security Advisory ALAS-2016-770.
#
include("compat.inc");
if (description)
{
script_id(94976);
script_version("3.2");
script_cvs_date("Date: 2018/04/18 15:09:36");
script_cve_id("CVE-2015-8325");
script_xref(name:"ALAS", value:"2016-770");
script_name(english:"Amazon Linux AMI : openssh (ALAS-2016-770)");
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 discovered that the OpenSSH sshd daemon fetched PAM environment
settings before running the login program. In configurations with
UseLogin=yes and the pam_env PAM module configured to read user
environment settings, a local user could use this flaw to execute
arbitrary code as root."
);
script_set_attribute(
attribute:"see_also",
value:"https://alas.aws.amazon.com/ALAS-2016-770.html"
);
script_set_attribute(
attribute:"solution",
value:"Run 'yum update openssh' 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:openssh");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssh-clients");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssh-debuginfo");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssh-keycat");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssh-ldap");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:openssh-server");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:pam_ssh_agent_auth");
script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux");
script_set_attribute(attribute:"patch_publication_date", value:"2016/11/18");
script_set_attribute(attribute:"plugin_publication_date", value:"2016/11/21");
script_end_attributes();
script_category(ACT_GATHER_INFO);
script_copyright(english:"This script is Copyright (C) 2016-2018 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:"openssh-6.6.1p1-31.62.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"openssh-clients-6.6.1p1-31.62.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"openssh-debuginfo-6.6.1p1-31.62.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"openssh-keycat-6.6.1p1-31.62.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"openssh-ldap-6.6.1p1-31.62.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"openssh-server-6.6.1p1-31.62.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"pam_ssh_agent_auth-0.9.3-9.31.62.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, "openssh / openssh-clients / openssh-debuginfo / openssh-keycat / etc");
}