Amazon Linux AMI : httpd24 (ALAS-2021-1543)

critical Nessus Plugin ID 154188

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Synopsis

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

Description

The version of httpd24 installed on the remote host is prior to 2.4.51-1.94. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS-2021-1543 advisory.

A NULL pointer dereference was found in Apache httpd mod_h2. The highest threat from this flaw is to system integrity. (CVE-2021-33193)

A NULL pointer dereference in httpd allows an unauthenticated remote attacker to crash httpd by providing malformed HTTP requests. The highest threat from this vulnerability is to system availability.
(CVE-2021-34798)

An out-of-bounds read in mod_proxy_uwsgi of httpd allows a remote unauthenticated attacker to crash the service through a crafted request. The highest threat from this vulnerability is to system availability.
(CVE-2021-36160)

An out-of-bounds write in function ap_escape_quotes of httpd allows an unauthenticated remote attacker to crash the server or potentially execute code on the system with the privileges of the httpd user, by providing malicious input to the function. (CVE-2021-39275)

A Server-Side Request Forgery (SSRF) flaw was found in mod_proxy of httpd. This flaw allows a remote, unauthenticated attacker to make the httpd server forward requests to an arbitrary server. The attacker could get, modify, or delete resources on other services that may be behind a firewall and inaccessible otherwise. The impact of this flaw varies based on what services and resources are available on the httpd network. (CVE-2021-40438)

While fuzzing the 2.4.49 httpd, a new null pointer dereference was detected during HTTP/2 request processing, allowing an external source to DoS the server. This requires a specially crafted request. The vulnerability was recently introduced in version 2.4.49. No exploit is known to the project.
(CVE-2021-41524)

A path transversal flaw was found in Apache 2.4.49. A remote attacker could use this flaw to map URLs to files outside the expected document root. Additionally this flaw could leak the source of interpreted files like CGI scripts. (CVE-2021-41773)

A path transversal and remote code execution flaw was found in Apache HTTP Server 2.4.49 and 2.4.50. A remote attacker could use this flaw to map URLs to files outside the expected document root. Additionally, this flaw could leak the source of interpreted files like CGI scripts. If files outside of these directories are not protected by the usual default configuration require all denied, these requests can succeed. If CGI scripts are also enabled for these aliased paths, this could allow for remote code execution. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability. This is an incomplete fix for CVE-2021-41773. (CVE-2021-42013)

Tenable has extracted the preceding description block directly from the tested product security advisory.

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

Solution

Run 'yum update httpd24' to update your system.

Plugin Details

Severity: Critical

ID: 154188

File Name: ala_ALAS-2021-1543.nasl

Version: 1.17

Type: local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 10/17/2021

Updated: 12/11/2024

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

Risk Information

VPR

Risk Factor: Critical

Score: 9.0

CVSS v2

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

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

CVSS Score Source: CVE-2021-42013

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 9.4

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:H/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:mod24_md, p-cpe:/a:amazon:linux:mod24_ssl, p-cpe:/a:amazon:linux:httpd24-devel, p-cpe:/a:amazon:linux:httpd24-debuginfo, p-cpe:/a:amazon:linux:mod24_ldap, p-cpe:/a:amazon:linux:mod24_proxy_html, p-cpe:/a:amazon:linux:httpd24-tools, p-cpe:/a:amazon:linux:mod24_session, p-cpe:/a:amazon:linux:httpd24-manual, p-cpe:/a:amazon:linux:httpd24, cpe:/o:amazon:linux

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

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 10/15/2021

Vulnerability Publication Date: 8/16/2021

CISA Known Exploited Vulnerability Due Dates: 11/17/2021, 12/15/2021

Exploitable With

CANVAS (CANVAS)

Metasploit (Apache 2.4.49/2.4.50 Traversal RCE)

Elliot (Apache 2.4.50 RCE)

Reference Information

CVE: CVE-2021-33193, CVE-2021-34798, CVE-2021-36160, CVE-2021-39275, CVE-2021-40438, CVE-2021-41524, CVE-2021-41773, CVE-2021-42013

ALAS: 2021-1543

IAVA: 2021-A-0440-S, 2021-A-0451-S

Detections

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