Debian DSA-4937-1 : apache2 - security update

critical Nessus Plugin ID 151485

Synopsis

The remote Debian host is missing one or more security-related updates.

Description

The remote Debian 10 host has packages installed that are affected by multiple vulnerabilities as referenced in the dsa-4937 advisory.

- 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)

- Apache HTTP Server protocol handler for the HTTP/2 protocol checks received request headers against the size limitations as configured for the server and used for the HTTP/1 protocol as well. On violation of these restrictions and HTTP response is sent to the client with a status code indicating why the request was rejected. This rejection response was not fully initialised in the HTTP/2 protocol handler if the offending header was the very first one received or appeared in a a footer. This led to a NULL pointer dereference on initialised memory, crashing reliably the child process. Since such a triggering HTTP/2 request is easy to craft and submit, this can be exploited to DoS the server. This issue affected mod_http2 1.15.17 and Apache HTTP Server version 2.4.47 only. Apache HTTP Server 2.4.47 was never released. (CVE-2021-31618)

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

Solution

Upgrade the apache2 packages.

For the stable distribution (buster), these problems have been fixed in version 2.4.38-3+deb10u5.

See Also

https://security-tracker.debian.org/tracker/source-package/apache2

https://www.debian.org/security/2021/dsa-4937

https://security-tracker.debian.org/tracker/CVE-2020-35452

https://security-tracker.debian.org/tracker/CVE-2021-26690

https://security-tracker.debian.org/tracker/CVE-2021-26691

https://security-tracker.debian.org/tracker/CVE-2021-30641

https://security-tracker.debian.org/tracker/CVE-2021-31618

https://packages.debian.org/source/buster/apache2

Plugin Details

Severity: Critical

ID: 151485

File Name: debian_DSA-4937.nasl

Version: 1.3

Type: local

Agent: unix

Published: 7/9/2021

Updated: 9/24/2021

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

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: High

Base Score: 7.5

Temporal Score: 5.5

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

CVSS Score Source: CVE-2021-26691

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

Vulnerability Information

CPE: p-cpe:/a:debian:debian_linux:apache2, p-cpe:/a:debian:debian_linux:apache2-bin, p-cpe:/a:debian:debian_linux:apache2-data, p-cpe:/a:debian:debian_linux:apache2-dev, p-cpe:/a:debian:debian_linux:apache2-doc, p-cpe:/a:debian:debian_linux:apache2-ssl-dev, p-cpe:/a:debian:debian_linux:apache2-suexec-custom, p-cpe:/a:debian:debian_linux:apache2-suexec-pristine, p-cpe:/a:debian:debian_linux:apache2-utils, p-cpe:/a:debian:debian_linux:libapache2-mod-md, p-cpe:/a:debian:debian_linux:libapache2-mod-proxy-uwsgi, cpe:/o:debian:debian_linux:10.0

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

Exploit Ease: No known exploits are available

Patch Publication Date: 7/8/2021

Vulnerability Publication Date: 6/1/2021

Reference Information

CVE: CVE-2020-35452, CVE-2021-26690, CVE-2021-26691, CVE-2021-30641, CVE-2021-31618

IAVA: 2021-A-0259-S