variot - var-201908-0266

var-201908-0266

Vulnerability from variot

Some HTTP/2 implementations are vulnerable to a header leak, potentially leading to a denial of service. The attacker sends a stream of headers with a 0-length header name and 0-length header value, optionally Huffman encoded into 1-byte or greater headers. Some implementations allocate memory for these headers and keep the allocation alive until the session dies. This can consume excess memory. Multiple HTTP/2 implementations are vulnerable to a variety of denial-of-service (DoS) attacks. HTTP/2 is the second version of the hypertext transfer protocol, which is mainly used to ensure the communication between the client and the server. A resource management error vulnerability exists in HTTP/2. A vulnerability in the HTTP/2 implementation of Nginx could allow an unauthenticated, remote malicious user to cause a denial of service (DoS) condition on a targeted system. The vulnerability is due to improper parsing of zero length headers by the affected software that could lead to excessive CPU usage. An attacker could exploit this vulnerability by sending a request that submits malicious input to an affected system. A successful exploit could result in a DoS condition on the targeted system. nginx.org has confirmed the vulnerability and released software updates. Solution:

Before applying this update, make sure all previously released errata relevant to your system have been applied. -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256

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Red Hat Security Advisory

Synopsis: Important: rh-nginx110-nginx security update Advisory ID: RHSA-2019:2745-01 Product: Red Hat Software Collections Advisory URL: https://access.redhat.com/errata/RHSA-2019:2745 Issue date: 2019-09-12 CVE Names: CVE-2019-9511 CVE-2019-9513 CVE-2019-9516 ==================================================================== 1. Summary:

An update for rh-nginx110-nginx is now available for Red Hat Software Collections.

Red Hat Product Security has rated this update as having a security impact of Important. 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.

Relevant releases/architectures:

Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 6) - x86_64 Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 7) - x86_64 Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.4) - x86_64 Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.5) - x86_64 Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.6) - x86_64 Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.7) - x86_64 Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 6) - x86_64 Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 7) - x86_64

Description:

nginx is a web and proxy server supporting HTTP and other protocols, with a focus on high concurrency, performance, and low memory usage.

Security Fix(es):

HTTP/2: large amount of data request leads to denial of service (CVE-2019-9511)
HTTP/2: flood using PRIORITY frames resulting in excessive resource consumption (CVE-2019-9513)
HTTP/2: 0-length headers leads to denial of service (CVE-2019-9516)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Solution:

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The rh-nginx110-nginx service must be restarted for this update to take effect.

Bugs fixed (https://bugzilla.redhat.com/):

1735741 - CVE-2019-9513 HTTP/2: flood using PRIORITY frames resulting in excessive resource consumption 1741860 - CVE-2019-9511 HTTP/2: large amount of data request leads to denial of service 1741864 - CVE-2019-9516 HTTP/2: 0-length headers leads to denial of service

Package List:

Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 6):

Source: rh-nginx110-nginx-1.10.2-9.el6.1.src.rpm

x86_64: rh-nginx110-nginx-1.10.2-9.el6.1.x86_64.rpm rh-nginx110-nginx-debuginfo-1.10.2-9.el6.1.x86_64.rpm rh-nginx110-nginx-mod-http-image-filter-1.10.2-9.el6.1.x86_64.rpm rh-nginx110-nginx-mod-http-perl-1.10.2-9.el6.1.x86_64.rpm rh-nginx110-nginx-mod-http-xslt-filter-1.10.2-9.el6.1.x86_64.rpm rh-nginx110-nginx-mod-mail-1.10.2-9.el6.1.x86_64.rpm rh-nginx110-nginx-mod-stream-1.10.2-9.el6.1.x86_64.rpm

Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 6):

Source: rh-nginx110-nginx-1.10.2-9.el6.1.src.rpm

Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 7):