Amazon Linux AMI : openssl (ALAS-2023-1843)

medium Nessus Plugin ID 182701

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Synopsis

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

Description

The version of openssl installed on the remote host is prior to 1.0.2k-16.164. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS-2023-1843 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 long delays. Where the key or parameters that are being checked have been obtained from an untrusted source this may lead to a Denial of Service. The function DH_check() performs various checks on DH parameters. One of those checks confirms that the modulus ('p' parameter) is not too large. Trying to use a very large modulus is slow and OpenSSL will not normally use a modulus which is over 10,000 bits in length. However the DH_check() function checks numerous aspects of the key or parameters that have been supplied. Some of those checks use the supplied modulus value even if it has already been found to be too large. An application that calls DH_check() and supplies a key or parameters obtained from 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() and EVP_PKEY_param_check(). Also vulnerable are the OpenSSL dhparam and pkeyparam command line applications when 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 long delays. Where the key or parameters that are being checked have been obtained from an untrusted source this may lead to a Denial of Service. The function DH_check() performs various checks on DH parameters. After fixing CVE-2023-3446 it was discovered that a large q parameter value can also trigger an overly long computation during some of these checks. A correct q value, if present, cannot be larger than the modulus p parameter, thus it is unnecessary to perform these checks if q is larger than p. An application that calls DH_check() and supplies a key or parameters obtained from 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() and EVP_PKEY_param_check().
Also vulnerable are the OpenSSL dhparam and pkeyparam command line applications when 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)

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: Medium

ID: 182701

File Name: ala_ALAS-2023-1843.nasl

Version: 1.0

Type: local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 10/6/2023

Updated: 10/6/2023

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

Risk Information

VPR

Risk Factor: Low

Score: 2.9

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

Vulnerability Information

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

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

Exploit Ease: No known exploits are available

Patch Publication Date: 9/27/2023

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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