It was found that the sandbox tool provided in policycoreutils was vulnerable to a TIOCSTI ioctl attack. A specially crafted program executed via the sandbox command could use this flaw to execute arbitrary commands in the context of the parent bash, escaping the sandbox.
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux AMI Security Advisory ALAS-2016-765.
#
include("compat.inc");
if (description)
{
script_id(94685);
script_version("2.3");
script_cvs_date("Date: 2018/04/18 15:09:36");
script_cve_id("CVE-2016-7545");
script_xref(name:"ALAS", value:"2016-765");
script_name(english:"Amazon Linux AMI : policycoreutils (ALAS-2016-765)");
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 the sandbox tool provided in policycoreutils was
vulnerable to a TIOCSTI ioctl attack. A specially crafted program
executed via the sandbox command could use this flaw to execute
arbitrary commands in the context of the parent bash, escaping the
sandbox."
);
script_set_attribute(
attribute:"see_also",
value:"https://alas.aws.amazon.com/ALAS-2016-765.html"
);
script_set_attribute(
attribute:"solution",
value:"Run 'yum update policycoreutils' 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:C/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:policycoreutils");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:policycoreutils-debuginfo");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:policycoreutils-newrole");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:policycoreutils-python");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:policycoreutils-restorecond");
script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux");
script_set_attribute(attribute:"patch_publication_date", value:"2016/11/10");
script_set_attribute(attribute:"plugin_publication_date", value:"2016/11/11");
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:"policycoreutils-2.1.12-5.25.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"policycoreutils-debuginfo-2.1.12-5.25.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"policycoreutils-newrole-2.1.12-5.25.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"policycoreutils-python-2.1.12-5.25.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"policycoreutils-restorecond-2.1.12-5.25.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, "policycoreutils / policycoreutils-debuginfo / etc");
}