CVSS2
Attack Vector
LOCAL
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
COMPLETE
Integrity Impact
COMPLETE
Availability Impact
COMPLETE
AV:L/AC:L/Au:N/C:C/I:C/A:C
CVSS3
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS
Percentile
87.3%
popd controlled free :
A denial of service flaw was found in the way bash handled popd commands. A poorly written shell script could cause bash to crash resulting in a local denial of service limited to a specific bash session.(CVE-2016-9401)
Arbitrary code execution via malicious hostname :
An arbitrary command injection flaw was found in the way bash processed the hostname value. A malicious DHCP server could use this flaw to execute arbitrary commands on the DHCP client machines running bash under specific circumstances.(CVE-2016-0634)
Specially crafted SHELLOPTS+PS4 variables allows command substitution :
An arbitrary command injection flaw was found in the way bash processed the SHELLOPTS and PS4 environment variables. A local, authenticated attacker could use this flaw to exploit poorly written setuid programs to elevate their privileges under certain circumstances. (CVE-2016-7543)
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux AMI Security Advisory ALAS-2017-878.
#
include("compat.inc");
if (description)
{
script_id(102866);
script_version("3.2");
script_cvs_date("Date: 2018/04/18 15:09:36");
script_cve_id("CVE-2016-0634", "CVE-2016-7543", "CVE-2016-9401");
script_xref(name:"ALAS", value:"2017-878");
script_name(english:"Amazon Linux AMI : bash (ALAS-2017-878)");
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:
"popd controlled free :
A denial of service flaw was found in the way bash handled popd
commands. A poorly written shell script could cause bash to crash
resulting in a local denial of service limited to a specific bash
session.(CVE-2016-9401)
Arbitrary code execution via malicious hostname :
An arbitrary command injection flaw was found in the way bash
processed the hostname value. A malicious DHCP server could use this
flaw to execute arbitrary commands on the DHCP client machines running
bash under specific circumstances.(CVE-2016-0634)
Specially crafted SHELLOPTS+PS4 variables allows command
substitution :
An arbitrary command injection flaw was found in the way bash
processed the SHELLOPTS and PS4 environment variables. A local,
authenticated attacker could use this flaw to exploit poorly written
setuid programs to elevate their privileges under certain
circumstances. (CVE-2016-7543)"
);
script_set_attribute(
attribute:"see_also",
value:"https://alas.aws.amazon.com/ALAS-2017-878.html"
);
script_set_attribute(
attribute:"solution",
value:"Run 'yum update bash' 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:N/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:bash");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:bash-debuginfo");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:bash-doc");
script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux");
script_set_attribute(attribute:"patch_publication_date", value:"2017/08/31");
script_set_attribute(attribute:"plugin_publication_date", value:"2017/09/01");
script_end_attributes();
script_category(ACT_GATHER_INFO);
script_copyright(english:"This script is Copyright (C) 2017-2018 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:"bash-4.2.46-28.37.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"bash-debuginfo-4.2.46-28.37.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"bash-doc-4.2.46-28.37.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, "bash / bash-debuginfo / bash-doc");
}
CVSS2
Attack Vector
LOCAL
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
COMPLETE
Integrity Impact
COMPLETE
Availability Impact
COMPLETE
AV:L/AC:L/Au:N/C:C/I:C/A:C
CVSS3
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS
Percentile
87.3%