Amazon Linux 2 : amazon-ssm-agent (ALAS-2024-2458)

critical Nessus Plugin ID 190697

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Synopsis

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

Description

The version of amazon-ssm-agent installed on the remote host is prior to 3.2.2222.0-1. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2024-2458 advisory.

- A malicious HTTP/2 client which rapidly creates requests and immediately resets them can cause excessive server resource consumption. While the total number of requests is bounded by the http2.Server.MaxConcurrentStreams setting, resetting an in-progress request allows the attacker to create a new request while the existing one is still executing. With the fix applied, HTTP/2 servers now bound the number of simultaneously executing handler goroutines to the stream concurrency limit (MaxConcurrentStreams). New requests arriving when at the limit (which can only happen after the client has reset an existing, in-flight request) will be queued until a handler exits. If the request queue grows too large, the server will terminate the connection. This issue is also fixed in golang.org/x/net/http2 for users manually configuring HTTP/2. The default stream concurrency limit is 250 streams (requests) per HTTP/2 connection. This value may be adjusted using the golang.org/x/net/http2 package; see the Server.MaxConcurrentStreams setting and the ConfigureServer function. (CVE-2023-39325)

- A malicious HTTP sender can use chunk extensions to cause a receiver reading from a request or response body to read many more bytes from the network than are in the body. A malicious HTTP client can further exploit this to cause a server to automatically read a large amount of data (up to about 1GiB) when a handler fails to read the entire body of a request. Chunk extensions are a little-used HTTP feature which permit including additional metadata in a request or response body sent using the chunked encoding. The net/http chunked encoding reader discards this metadata. A sender can exploit this by inserting a large metadata segment with each byte transferred. The chunk reader now produces an error if the ratio of real body to encoded bytes grows too small. (CVE-2023-39326)

- A denial of service (DoS) vulnerability was discovered in go-git versions prior to v5.11. This vulnerability allows an attacker to perform denial of service attacks by providing specially crafted responses from a Git server which triggers resource exhaustion in go-git clients. Applications using only the in-memory filesystem supported by go-git are not affected by this vulnerability. This is a go-git implementation issue and does not affect the upstream git cli. (CVE-2023-49568)

- A path traversal vulnerability was discovered in go-git versions prior to v5.11. This vulnerability allows an attacker to create and amend files across the filesystem. In the worse case scenario, remote code execution could be achieved. Applications are only affected if they are using the ChrootOS https://pkg.go.dev/github.com/go-git/go-billy/v5/osfs#ChrootOS , which is the default when using Plain versions of Open and Clone funcs (e.g. PlainClone). Applications using BoundOS https://pkg.go.dev/github.com/go-git/go-billy/v5/osfs#BoundOS or in-memory filesystems are not affected by this issue. This is a go-git implementation issue and does not affect the upstream git cli.
(CVE-2023-49569)

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 amazon-ssm-agent' to update your system.

Plugin Details

Severity: Critical

ID: 190697

File Name: al2_ALAS-2024-2458.nasl

Version: 1.2

Type: local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 2/19/2024

Updated: 4/25/2024

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

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 7.4

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

CVSS Score Source: CVE-2023-49569

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:amazon:linux:amazon-ssm-agent-debuginfo, cpe:/o:amazon:linux:2, p-cpe:/a:amazon:linux:amazon-ssm-agent

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

Exploit Ease: No known exploits are available

Patch Publication Date: 2/15/2024

Vulnerability Publication Date: 1/9/2024

Reference Information

CVE: CVE-2023-39325, CVE-2023-39326, CVE-2023-49568, CVE-2023-49569

Detections

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