Amazon Linux 2023 : amazon-cloudwatch-agent (ALAS2023-2025-968)

high Nessus Plugin ID 235902

Synopsis

The remote Amazon Linux 2023 host is missing a security update.

Description

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2025-968 advisory.

The net/http package accepted data in the chunked transfer encoding containing an invalid chunk-size line terminated by a bare LF. When used in conjunction with a server or proxy which incorrectly interprets a bare LF in a chunk extension as part of the extension, this could permit request smuggling.
(CVE-2025-22871)

Expr is an expression language and expression evaluation for Go. Prior to version 1.17.0, if the Expr expression parser is given an unbounded input string, it will attempt to compile the entire string and generate an Abstract Syntax Tree (AST) node for each part of the expression. In scenarios where input size isn't limited, a malicious or inadvertent extremely large expression can consume excessive memory as the parser builds a huge AST. This can ultimately lead to*excessive memory usage and an Out-Of-Memory (OOM) crash of the process. This issue is relatively uncommon and will only manifest when there are no restrictions on the input size, i.e. the expression length is allowed to grow arbitrarily large. In typical use cases where inputs are bounded or validated, this problem would not occur. The problem has been patched in the latest versions of the Expr library. The fix introduces compile-time limits on the number of AST nodes and memory usage during parsing, preventing any single expression from exhausting resources. Users should upgrade to Expr version 1.17.0 or later, as this release includes the new node budget and memory limit safeguards. Upgrading to v1.17.0 ensures that extremely deep or large expressions are detected and safely aborted during compilation, avoiding the OOM condition. For users who cannot immediately upgrade, the recommended workaround is to impose an input size restriction before parsing. In practice, this means validating or limiting the length of expression strings that your application will accept. For example, set a maximum allowable number of characters (or nodes) for any expression and reject or truncate inputs that exceed this limit. By ensuring no unbounded-length expression is ever fed into the parser, one can prevent the parser from constructing a pathologically large AST and avoid potential memory exhaustion. In short, pre-validate and cap input size as a safeguard in the absence of the patch.
(CVE-2025-29786)

golang-jwt is a Go implementation of JSON Web Tokens. Prior to5.2.2 and 4.5.2, the function parse.ParseUnverified splits (via a call to strings.Split) its argument (which is untrusted data) on periods. As a result, in the face of a malicious request whose Authorization header consists of Bearer followed by many period characters, a call to that function incurs allocations to the tune of O(n) bytes (where n stands for the length of the function's argument), with a constant factor of about 16. This issue is fixed in 5.2.2 and 4.5.2. (CVE-2025-30204)

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 'dnf update amazon-cloudwatch-agent --releasever 2023.7.20250512' to update your system.

Plugin Details

Severity: High

ID: 235902

File Name: al2023_ALAS2023-2025-968.nasl

Version: 1.1

Type: local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 5/13/2025

Updated: 5/13/2025

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.0

CVSS v2

Risk Factor: High

Base Score: 9.4

Temporal Score: 7

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

CVSS Score Source: CVE-2025-22871

CVSS v3

Risk Factor: Critical

Base Score: 9.1

Temporal Score: 7.9

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

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

CVSS v4

Risk Factor: High

Base Score: 8.7

Threat Score: 6.6

Threat Vector: CVSS:4.0/E:U

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

CVSS Score Source: CVE-2025-30204

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:amazon-cloudwatch-agent, cpe:/o:amazon:linux:2023

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

Exploit Ease: No known exploits are available

Patch Publication Date: 5/13/2025

Vulnerability Publication Date: 3/17/2025

Reference Information

CVE: CVE-2025-22871, CVE-2025-29786, CVE-2025-30204

IAVB: 2025-B-0048-S

Detections

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