Amazon Linux 2 : unbound (ALAS-2021-1683)

critical Nessus Plugin ID 151275
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Synopsis

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

Description

The version of unbound installed on the remote host is prior to 1.7.3-15. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2021-1683 advisory.

- ** DISPUTED ** Unbound before 1.9.5 allows an integer overflow in the regional allocator via regional_alloc. NOTE: The vendor disputes that this is a vulnerability. Although the code may be vulnerable, a running Unbound installation cannot be remotely or locally exploited. (CVE-2019-25032)

- ** DISPUTED ** Unbound before 1.9.5 allows an integer overflow in sldns_str2wire_dname_buf_origin, leading to an out-of-bounds write. NOTE: The vendor disputes that this is a vulnerability. Although the code may be vulnerable, a running Unbound installation cannot be remotely or locally exploited. (CVE-2019-25034)

- ** DISPUTED ** Unbound before 1.9.5 allows an out-of-bounds write in sldns_bget_token_par. NOTE: The vendor disputes that this is a vulnerability. Although the code may be vulnerable, a running Unbound installation cannot be remotely or locally exploited. (CVE-2019-25035)

- ** DISPUTED ** Unbound before 1.9.5 allows an assertion failure and denial of service in synth_cname.
NOTE: The vendor disputes that this is a vulnerability. Although the code may be vulnerable, a running Unbound installation cannot be remotely or locally exploited. (CVE-2019-25036)

- ** DISPUTED ** Unbound before 1.9.5 allows an assertion failure and denial of service in dname_pkt_copy via an invalid packet. NOTE: The vendor disputes that this is a vulnerability. Although the code may be vulnerable, a running Unbound installation cannot be remotely or locally exploited. (CVE-2019-25037)

- ** DISPUTED ** Unbound before 1.9.5 allows an integer overflow in a size calculation in dnscrypt/dnscrypt.c. NOTE: The vendor disputes that this is a vulnerability. Although the code may be vulnerable, a running Unbound installation cannot be remotely or locally exploited. (CVE-2019-25038)

- ** DISPUTED ** Unbound before 1.9.5 allows an integer overflow in a size calculation in respip/respip.c.
NOTE: The vendor disputes that this is a vulnerability. Although the code may be vulnerable, a running Unbound installation cannot be remotely or locally exploited. (CVE-2019-25039)

- ** DISPUTED ** Unbound before 1.9.5 allows an infinite loop via a compressed name in dname_pkt_copy. NOTE:
The vendor disputes that this is a vulnerability. Although the code may be vulnerable, a running Unbound installation cannot be remotely or locally exploited. (CVE-2019-25040)

- ** DISPUTED ** Unbound before 1.9.5 allows an assertion failure via a compressed name in dname_pkt_copy.
NOTE: The vendor disputes that this is a vulnerability. Although the code may be vulnerable, a running Unbound installation cannot be remotely or locally exploited. (CVE-2019-25041)

- ** DISPUTED ** Unbound before 1.9.5 allows an out-of-bounds write via a compressed name in rdata_copy.
NOTE: The vendor disputes that this is a vulnerability. Although the code may be vulnerable, a running Unbound installation cannot be remotely or locally exploited. (CVE-2019-25042)

- NLnet Labs Unbound, up to and including version 1.12.0, and NLnet Labs NSD, up to and including version 4.3.3, contain a local vulnerability that would allow for a local symlink attack. When writing the PID file, Unbound and NSD create the file if it is not there, or open an existing file for writing. In case the file was already present, they would follow symlinks if the file happened to be a symlink instead of a regular file. An additional chown of the file would then take place after it was written, making the user Unbound/NSD is supposed to run as the new owner of the file. If an attacker has local access to the user Unbound/NSD runs as, she could create a symlink in place of the PID file pointing to a file that she would like to erase. If then Unbound/NSD is killed and the PID file is not cleared, upon restarting with root privileges, Unbound/NSD will rewrite any file pointed at by the symlink. This is a local vulnerability that could create a Denial of Service of the system Unbound/NSD is running on. It requires an attacker having access to the limited permission user Unbound/NSD runs as and point through the symlink to a critical file on the system. (CVE-2020-28935)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Run 'yum update unbound' to update your system.

See Also

https://alas.aws.amazon.com/AL2/ALAS-2021-1683.html

https://access.redhat.com/security/cve/CVE-2019-25032

https://access.redhat.com/security/cve/CVE-2019-25034

https://access.redhat.com/security/cve/CVE-2019-25035

https://access.redhat.com/security/cve/CVE-2019-25036

https://access.redhat.com/security/cve/CVE-2019-25037

https://access.redhat.com/security/cve/CVE-2019-25038

https://access.redhat.com/security/cve/CVE-2019-25039

https://access.redhat.com/security/cve/CVE-2019-25040

https://access.redhat.com/security/cve/CVE-2019-25041

https://access.redhat.com/security/cve/CVE-2019-25042

https://access.redhat.com/security/cve/CVE-2020-28935

Plugin Details

Severity: Critical

ID: 151275

File Name: al2_ALAS-2021-1683.nasl

Version: 1.2

Type: local

Agent: unix

Published: 7/1/2021

Updated: 7/1/2021

Dependencies: ssh_get_info.nasl

Risk Information

CVSS Score Source: CVE-2019-25042

VPR

Risk Factor: Medium

Score: 5.9

CVSS v2

Risk Factor: High

Base Score: 7.5

Temporal Score: 5.5

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

Temporal Vector: E:U/RL:OF/RC:C

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: E:U/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:python2-unbound, p-cpe:/a:amazon:linux:python3-unbound, p-cpe:/a:amazon:linux:unbound, p-cpe:/a:amazon:linux:unbound-debuginfo, p-cpe:/a:amazon:linux:unbound-devel, p-cpe:/a:amazon:linux:unbound-libs, cpe:/o:amazon:linux:2

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

Exploit Ease: No known exploits are available

Patch Publication Date: 7/1/2021

Vulnerability Publication Date: 12/7/2020

Reference Information

CVE: CVE-2019-25032, CVE-2019-25034, CVE-2019-25035, CVE-2019-25036, CVE-2019-25037, CVE-2019-25038, CVE-2019-25039, CVE-2019-25040, CVE-2019-25041, CVE-2019-25042, CVE-2020-28935

ALAS: 2021-1683