Amazon Linux 2 : openssl (ALAS-2023-2246)

critical Nessus Plugin ID 181360

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Synopsis

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

Description

The version of openssl installed on the remote host is prior to 1.0.2k-24. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2023-2246 advisory.

Issue summary: Checking excessively long DH keys or parameters may be very slow.

Impact summary: Applications that use the functions DH_check(), DH_check_ex()or EVP_PKEY_param_check() to check a DH key or DH parameters may experience longdelays. Where the key or parameters that are being checked have been obtainedfrom an untrusted source this may lead to a Denial of Service.

The function DH_check() performs various checks on DH parameters. One of thosechecks confirms that the modulus ('p' parameter) is not too large. Trying to usea very large modulus is slow and OpenSSL will not normally use a modulus whichis over 10,000 bits in length.

However the DH_check() function checks numerous aspects of the key or parametersthat have been supplied.
Some of those checks use the supplied modulus valueeven if it has already been found to be too large.

An application that calls DH_check() and supplies a key or parameters obtainedfrom an untrusted source could be vulernable to a Denial of Service attack.

The function DH_check() is itself called by a number of other OpenSSL functions.An application calling any of those other functions may similarly be affected.The other functions affected by this are DH_check_ex() andEVP_PKEY_param_check().

Also vulnerable are the OpenSSL dhparam and pkeyparam command line applicationswhen using the '-check' option.

The OpenSSL SSL/TLS implementation is not affected by this issue.The OpenSSL 3.0 and 3.1 FIPS providers are not affected by this issue. (CVE-2023-3446)

Issue summary: Checking excessively long DH keys or parameters may be very slow.

Impact summary: Applications that use the functions DH_check(), DH_check_ex()or EVP_PKEY_param_check() to check a DH key or DH parameters may experience longdelays. Where the key or parameters that are being checked have been obtainedfrom an untrusted source this may lead to a Denial of Service.

The function DH_check() performs various checks on DH parameters. After fixingCVE-2023-3446 it was discovered that a large q parameter value can also triggeran overly long computation during some of these checks. A correct q value,if present, cannot be larger than the modulus p parameter, thus it isunnecessary to perform these checks if q is larger than p.

An application that calls DH_check() and supplies a key or parameters obtainedfrom an untrusted source could be vulnerable to a Denial of Service attack.

The function DH_check() is itself called by a number of other OpenSSL functions.An application calling any of those other functions may similarly be affected.The other functions affected by this are DH_check_ex() andEVP_PKEY_param_check().

Also vulnerable are the OpenSSL dhparam and pkeyparam command line applicationswhen using the -check option.

The OpenSSL SSL/TLS implementation is not affected by this issue.

The OpenSSL 3.0 and 3.1 FIPS providers are not affected by this issue. (CVE-2023-3817)

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 openssl' to update your system.

Plugin Details

Severity: Critical

ID: 181360

File Name: al2_ALAS-2023-2246.nasl

Version: 1.2

Type: local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 9/13/2023

Updated: 12/11/2024

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

Risk Information

VPR

Risk Factor: Low

Score: 2.2

CVSS v2

Risk Factor: Medium

Base Score: 5

Temporal Score: 3.7

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

CVSS Score Source: CVE-2023-3817

CVSS v3

Risk Factor: Medium

Base Score: 5.3

Temporal Score: 4.6

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

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

CVSS v4

Risk Factor: Critical

Base Score: 9.3

Threat Score: 8.1

Threat Vector: CVSS:4.0/E:U

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS Score Source: CVE-2023-3446

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:openssl-perl, p-cpe:/a:amazon:linux:openssl-static, cpe:/o:amazon:linux:2, p-cpe:/a:amazon:linux:openssl-devel, p-cpe:/a:amazon:linux:openssl-debuginfo, p-cpe:/a:amazon:linux:openssl, p-cpe:/a:amazon:linux:openssl-libs

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

Exploit Ease: No known exploits are available

Patch Publication Date: 9/8/2023

Vulnerability Publication Date: 7/13/2023

Reference Information

CVE: CVE-2023-3446, CVE-2023-3817

IAVA: 2023-A-0398-S

Detections

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