nginx < 1.16.1 (stable) / 1.17.3 (mainline) Multiple DoS

high Nessus Network Monitor Plugin ID 701146

Synopsis

The remote web server is running a version of nginx that is affected by multiple DoS vulnerabilities.

Description

The remote web server is running a version of nginx that is affected by the following vulnerabilities:

- A vulnerability exists that involves window size manipulation and stream prioritization manipulation, potentially leading to a denial of service. An attacker can manipulate window size and stream priority to force the server to queue the data in 1-byte chunks. Depending on how efficiently this data is queued, this can consume excess CPU, memory, or both. (CVE-2019-9511)
- The affected versions of nginx are vulnerable to resource loops, potentially leading to a denial of service. The attacker creates multiple request streams and continually shuffles the priority of the streams in a way that causes substantial churn to the priority tree. This can consume excess CPU. (CVE-2019-9513)
- The affected versions of nginx 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. (CVE-2019-9516)

Solution

Patches are available and the problem is fixed in nginx versions 1.16.1 (stable) and 1.17.3 (mainline).

See Also

https://www.nginx.com/blog/nginx-updates-mitigate-august-2019-http-2-vulnerabilities

https://www.tenable.com/blog/multiple-denial-of-service-dos-vulnerabilities-in-http2-disclosed-cve-2019-9511-cve-2019-9518

Plugin Details

Severity: High

ID: 701146

Family: Web Servers

Published: 8/14/2019

Updated: 8/14/2019

Risk Information

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

Temporal Vector: CVSS2#E:U/RL:OF/RC:C

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:2.3:a:igor_sysoev:nginx:*:*:*:*:*:*:*:*

Patch Publication Date: 8/13/2019

Vulnerability Publication Date: 8/13/2019

Reference Information

CVE: CVE-2019-9511, CVE-2019-9513, CVE-2019-9516