Amazon Linux 2 : mod_http2 (ALAS-2019-1342) (0-Length Headers Leak) (Data Dribble) (Internal Data Buffering)

high Nessus Plugin ID 130401

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Synopsis

The remote Amazon Linux 2 host is missing a security update.

Description

Some HTTP/2 implementations are vulnerable to window size manipulation and stream prioritization manipulation, potentially leading to a denial of service. The attacker requests a large amount of data from a specified resource over multiple streams. They 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)

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.(CVE-2019-9516)

Some HTTP/2 implementations are vulnerable to unconstrained interal data buffering, potentially leading to a denial of service. The attacker opens the HTTP/2 window so the peer can send without constraint; however, they leave the TCP window closed so the peer cannot actually write (many of) the bytes on the wire. The attacker then sends a stream of requests for a large response object. Depending on how the servers queue the responses, this can consume excess memory, CPU, or both.(CVE-2019-9517)

Solution

Run 'yum update mod_http2' to update your system.

See Also

https://alas.aws.amazon.com/AL2/ALAS-2019-1342.html

Plugin Details

Severity: High

ID: 130401

File Name: al2_ALAS-2019-1342.nasl

Version: 1.2

Type: local

Agent: unix

Published: 10/31/2019

Updated: 12/17/2019

Supported Sensors: Frictionless Assessment Agent, Frictionless Assessment AWS, Nessus Agent

Risk Information

VPR

Risk Factor: Medium

Score: 5.1

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

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

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

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:mod_http2, p-cpe:/a:amazon:linux:mod_http2-debuginfo, cpe:/o:amazon:linux:2

Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list

Exploit Ease: No known exploits are available

Patch Publication Date: 10/30/2019

Vulnerability Publication Date: 8/13/2019

Reference Information

CVE: CVE-2019-9511, CVE-2019-9516, CVE-2019-9517

ALAS: 2019-1342