Amazon Linux 2 : dhcp (ALAS-2022-1874)

medium Nessus Plugin ID 167240

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Synopsis

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

Description

The version of dhcp installed on the remote host is prior to 4.2.5-79. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2022-1874 advisory.

An integer overflow vulnerability was found in the DHCP server. When the option_code_hash_lookup() function is called from add_option(), it increases the option's refcount field. However, there is not a corresponding call to option_dereference() to decrement the refcount field. The add_option() function is only used in server responses to lease query packets. Each lease query response calls this function for several options. Hence, a DHCP server configured with allow lease query a remote machine with access to the server, can send lease queries for the same lease multiple times, leading to the add_option() function being called repeatedly. This issue could cause the reference counters to overflow and the server to abort or crash. (CVE-2022-2928)

A vulnerability was found in the DHCP server where the fqdn_universe_decode() function allocates buffer space for the contents of option 81 (fqdn) data received in a DHCP packet. The maximum length of a DNS label is 63 bytes. The function tests the length byte of each label contained in the fqdn; if it finds a label whose length byte value is larger than 63, it returns without dereferencing the buffer space. This issue causes a memory leak. On a system with access to a DHCP server, an attacker from any adjacent network could send DHCP packets crafted to include fqdn labels longer than 63 bytes to the DHCP server, eventually causing the server to run out of memory and crash. (CVE-2022-2929)

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 dhcp' to update your system.

Plugin Details

Severity: Medium

ID: 167240

File Name: al2_ALAS-2022-1874.nasl

Version: 1.5

Type: local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 11/9/2022

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: 3.6

CVSS v2

Risk Factor: Medium

Base Score: 6.1

Temporal Score: 4.5

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

CVSS Score Source: CVE-2022-2929

CVSS v3

Risk Factor: Medium

Base Score: 6.5

Temporal Score: 5.7

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

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

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:dhcp-common, p-cpe:/a:amazon:linux:dhclient, p-cpe:/a:amazon:linux:dhcp, cpe:/o:amazon:linux:2, p-cpe:/a:amazon:linux:dhcp-libs, p-cpe:/a:amazon:linux:dhcp-devel, p-cpe:/a:amazon:linux:dhcp-debuginfo

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

Exploit Ease: No known exploits are available

Patch Publication Date: 10/31/2022

Vulnerability Publication Date: 10/6/2022

Reference Information

CVE: CVE-2022-2928, CVE-2022-2929

IAVB: 2022-B-0037

Detections

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