Ubuntu 18.04 LTS / 20.04 LTS / 20.10 / 21.04 : Apache HTTP Server vulnerabilities (USN-4994-1)

critical Nessus Plugin ID 150940
New! Plugin Severity Now Using CVSS v3

The calculated severity for Plugins has been updated to use CVSS v3 by default. Plugins that do not have a CVSS v3 score will fall back to CVSS v2 for calculating severity. Severity display preferences can be toggled in the settings dropdown.

Synopsis

The remote Ubuntu host is missing one or more security updates.

Description

The remote Ubuntu 18.04 LTS / 20.04 LTS / 20.10 / 21.04 host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-4994-1 advisory.

- Apache HTTP Server versions 2.4.41 to 2.4.46 mod_proxy_http can be made to crash (NULL pointer dereference) with specially crafted requests using both Content-Length and Transfer-Encoding headers, leading to a Denial of Service (CVE-2020-13950)

- Apache HTTP Server versions 2.4.0 to 2.4.46 A specially crafted Digest nonce can cause a stack overflow in mod_auth_digest. There is no report of this overflow being exploitable, nor the Apache HTTP Server team could create one, though some particular compiler and/or compilation option might make it possible, with limited consequences anyway due to the size (a single byte) and the value (zero byte) of the overflow (CVE-2020-35452)

- Apache HTTP Server versions 2.4.0 to 2.4.46 A specially crafted Cookie header handled by mod_session can cause a NULL pointer dereference and crash, leading to a possible Denial Of Service (CVE-2021-26690)

- In Apache HTTP Server versions 2.4.0 to 2.4.46 a specially crafted SessionHeader sent by an origin server could cause a heap overflow (CVE-2021-26691)

- Apache HTTP Server versions 2.4.39 to 2.4.46 Unexpected matching behavior with 'MergeSlashes OFF' (CVE-2021-30641)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Update the affected packages.

See Also

https://ubuntu.com/security/notices/USN-4994-1

Plugin Details

Severity: Critical

ID: 150940

File Name: ubuntu_USN-4994-1.nasl

Version: 1.4

Type: local

Agent: unix

Published: 6/21/2021

Updated: 9/24/2021

Dependencies: ssh_get_info.nasl

Risk Information

CVSS Score Source: CVE-2021-26691

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: High

Base Score: 7.5

Temporal Score: 5.5

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

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

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.5

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

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

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:18.04:-:lts, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, cpe:/o:canonical:ubuntu_linux:20.10, cpe:/o:canonical:ubuntu_linux:21.04, p-cpe:/a:canonical:ubuntu_linux:apache2, p-cpe:/a:canonical:ubuntu_linux:apache2-bin, p-cpe:/a:canonical:ubuntu_linux:apache2-data, p-cpe:/a:canonical:ubuntu_linux:apache2-dev, p-cpe:/a:canonical:ubuntu_linux:apache2-ssl-dev, p-cpe:/a:canonical:ubuntu_linux:apache2-suexec-custom, p-cpe:/a:canonical:ubuntu_linux:apache2-suexec-pristine, p-cpe:/a:canonical:ubuntu_linux:apache2-utils, p-cpe:/a:canonical:ubuntu_linux:libapache2-mod-md, p-cpe:/a:canonical:ubuntu_linux:libapache2-mod-proxy-uwsgi

Required KB Items: Host/cpu, Host/Ubuntu, Host/Ubuntu/release, Host/Debian/dpkg-l

Exploit Ease: No known exploits are available

Patch Publication Date: 6/21/2021

Vulnerability Publication Date: 6/1/2021

Reference Information

CVE: CVE-2020-13950, CVE-2020-35452, CVE-2021-26690, CVE-2021-26691, CVE-2021-30641

USN: 4994-1

IAVA: 2021-A-0259-S