CVE-2019-9511
Description
A flaw was found in HTTP/2. An attacker can request a large amount of data by manipulating 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 queue can consume excess CPU, memory, or both, leading to a denial of service. The highest threat from this vulnerability is to system availability.
Statement
There are no mitigations available for nghttp2 and nodejs. Both packages will be updated once the available fixes are released for Red Hat Enterprise Linux and Red Hat Software Collections.
The nodejs RPM shipped in OpenShift Container Platform 3.9 and 3.10 is not affected by this flaw as it does not contain the vulnerable code.
Mitigation
Red Hat Quay 3.0 uses Nginx 1.12 from Red Hat Software Collections. It will be updated once a fixed is released for Software Collections. In the meantime users of Quay can disable http/2 support in Nginx by following these instructions:
1. Copy the Nginx configuration from the quay container to the host
$ docker cp 3aadf1421ba3:/quay-registry/conf/nginx/ /mnt/quay/nginx
2. Edit the Nginx configuration, removing http/2 support
$ sed -i 's/http2 //g' /mnt/quay/nginx/nginx.conf
3. Restart Nginx with the new configuration mounted into the container, eg:
$ docker run --restart=always -p 443:8443 -p 80:8080 --sysctl net.core.somaxconn=4096 -v /mnt/quay/config:/conf/stack:Z -v /mnt/quay/storage:/datastorage -v /mnt/quay/nginx:/quay-registry/config/nginx:Z -d quay.io/redhat/quay:v3.0.3
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.5 | 7.5 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | Low | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
If an attacker can trigger the allocation of the limited resources, but the number or size of the resources is not controlled, then the most common result is denial of service. This would prevent valid users from accessing the product, and it could potentially have an impact on the surrounding environment, i.e., the product may slow down, crash due to unhandled errors, or lock out legitimate users. For example, a memory exhaustion attack against an application could slow down the application as well as its host operating system.
Access Control,Other
Technical Impact: Bypass Protection Mechanism; Other
In some cases it may be possible to force the product to "fail open" in the event of resource exhaustion. The state of the product -- and possibly the security functionality - may then be compromised.
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