CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:N/I:N/A:P
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
AI Score
Confidence
High
EPSS
Percentile
85.5%
In nghttp2 before version 1.41.0, the overly large HTTP/2 SETTINGS frame payload causes denial of service. The proof of concept attack involves a malicious client constructing a SETTINGS frame with a length of 14,400 bytes (2400 individual settings entries) over and over again. The attack causes the CPU to spike at 100%. nghttp2 v1.41.0 fixes this vulnerability. There is a workaround to this vulnerability. Implement nghttp2_on_frame_recv_callback callback, and if received frame is SETTINGS frame and the number of settings entries are large (e.g., > 32), then drop the connection. (CVE-2020-11080)
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux 2 Security Advisory ALAS-2020-1445.
#
include('compat.inc');
if (description)
{
script_id(138047);
script_version("1.4");
script_set_attribute(attribute:"plugin_modification_date", value:"2024/03/05");
script_cve_id("CVE-2020-11080");
script_xref(name:"ALAS", value:"2020-1445");
script_xref(name:"CEA-ID", value:"CEA-2021-0004");
script_name(english:"Amazon Linux 2 : nghttp2 (ALAS-2020-1445)");
script_set_attribute(attribute:"synopsis", value:
"The remote Amazon Linux 2 host is missing a security update.");
script_set_attribute(attribute:"description", value:
"In nghttp2 before version 1.41.0, the overly large HTTP/2 SETTINGS
frame payload causes denial of service. The proof of concept attack
involves a malicious client constructing a SETTINGS frame with a
length of 14,400 bytes (2400 individual settings entries) over and
over again. The attack causes the CPU to spike at 100%. nghttp2
v1.41.0 fixes this vulnerability. There is a workaround to this
vulnerability. Implement nghttp2_on_frame_recv_callback callback, and
if received frame is SETTINGS frame and the number of settings entries
are large (e.g., > 32), then drop the connection. (CVE-2020-11080)");
script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/AL2/ALAS-2020-1445.html");
script_set_attribute(attribute:"solution", value:
"Run 'yum update nghttp2' to update your system.");
script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P");
script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H");
script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-11080");
script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
script_set_attribute(attribute:"exploit_available", value:"false");
script_set_attribute(attribute:"vuln_publication_date", value:"2020/06/03");
script_set_attribute(attribute:"patch_publication_date", value:"2020/07/01");
script_set_attribute(attribute:"plugin_publication_date", value:"2020/07/02");
script_set_attribute(attribute:"plugin_type", value:"local");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:libnghttp2");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:libnghttp2-devel");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:nghttp2");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:nghttp2-debuginfo");
script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux:2");
script_set_attribute(attribute:"generated_plugin", value:"current");
script_end_attributes();
script_category(ACT_GATHER_INFO);
script_family(english:"Amazon Linux Local Security Checks");
script_copyright(english:"This script is Copyright (C) 2020-2024 and is owned by Tenable, Inc. or an Affiliate thereof.");
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 != "2")
{
if (os_ver == 'A') os_ver = 'AMI';
audit(AUDIT_OS_NOT, "Amazon Linux 2", "Amazon Linux " + os_ver);
}
if (!get_kb_item("Host/AmazonLinux/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);
flag = 0;
if (rpm_check(release:"AL2", reference:"libnghttp2-1.41.0-1.amzn2")) flag++;
if (rpm_check(release:"AL2", reference:"libnghttp2-devel-1.41.0-1.amzn2")) flag++;
if (rpm_check(release:"AL2", reference:"nghttp2-1.41.0-1.amzn2")) flag++;
if (rpm_check(release:"AL2", reference:"nghttp2-debuginfo-1.41.0-1.amzn2")) 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, "libnghttp2 / libnghttp2-devel / nghttp2 / nghttp2-debuginfo");
}
Vendor | Product | Version | CPE |
---|---|---|---|
amazon | linux | nghttp2-debuginfo | p-cpe:/a:amazon:linux:nghttp2-debuginfo |
amazon | linux | libnghttp2 | p-cpe:/a:amazon:linux:libnghttp2 |
amazon | linux | 2 | cpe:/o:amazon:linux:2 |
amazon | linux | nghttp2 | p-cpe:/a:amazon:linux:nghttp2 |
amazon | linux | libnghttp2-devel | p-cpe:/a:amazon:linux:libnghttp2-devel |
CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:N/I:N/A:P
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
AI Score
Confidence
High
EPSS
Percentile
85.5%