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Ubuntu 18.04 LTS / 20.04 LTS : Unbound vulnerabilities (USN-4938-1)

critical Nessus Plugin ID 149324

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Synopsis

The remote Ubuntu host is missing one or more security updates.

Description

The remote Ubuntu 18.04 LTS / 20.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-4938-1 advisory.

 - Unbound before 1.9.5 allows configuration injection in create_unbound_ad_servers.sh upon a successful man- in-the-middle attack against a cleartext HTTP session. (CVE-2019-25031)

 - Unbound before 1.9.5 allows an integer overflow in the regional allocator via regional_alloc.
 (CVE-2019-25032)

 - Unbound before 1.9.5 allows an integer overflow in the regional allocator via the ALIGN_UP macro.
 (CVE-2019-25033)

 - Unbound before 1.9.5 allows an integer overflow in sldns_str2wire_dname_buf_origin, leading to an out-of- bounds write. (CVE-2019-25034)

 - Unbound before 1.9.5 allows an out-of-bounds write in sldns_bget_token_par. (CVE-2019-25035)

 - Unbound before 1.9.5 allows an assertion failure and denial of service in synth_cname. (CVE-2019-25036)

 - Unbound before 1.9.5 allows an assertion failure and denial of service in dname_pkt_copy via an invalid packet. (CVE-2019-25037)

 - Unbound before 1.9.5 allows an integer overflow in a size calculation in dnscrypt/dnscrypt.c.
 (CVE-2019-25038)

 - Unbound before 1.9.5 allows an integer overflow in a size calculation in respip/respip.c. (CVE-2019-25039)

 - Unbound before 1.9.5 allows an infinite loop via a compressed name in dname_pkt_copy. (CVE-2019-25040)

 - Unbound before 1.9.5 allows an assertion failure via a compressed name in dname_pkt_copy. (CVE-2019-25041)

 - Unbound before 1.9.5 allows an out-of-bounds write via a compressed name in rdata_copy. (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

Update the affected packages.

See Also

https://ubuntu.com/security/notices/USN-4938-1

Plugin Details

Severity: Critical

ID: 149324

File Name: ubuntu_USN-4938-1.nasl

Version: 1.4

Type: local

Agent: unix

Published: 5/6/2021

Updated: 10/16/2023

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

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: High

Base Score: 7.5

Temporal Score: 5.5

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

CVSS Score Source: CVE-2019-25042

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: cpe:/o:canonical:ubuntu_linux:18.04:-:lts, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:libunbound-dev, p-cpe:/a:canonical:ubuntu_linux:libunbound2, p-cpe:/a:canonical:ubuntu_linux:libunbound8, p-cpe:/a:canonical:ubuntu_linux:python-unbound, p-cpe:/a:canonical:ubuntu_linux:python3-unbound, p-cpe:/a:canonical:ubuntu_linux:unbound, p-cpe:/a:canonical:ubuntu_linux:unbound-anchor, p-cpe:/a:canonical:ubuntu_linux:unbound-host

Required KB Items: Host/cpu, Host/Ubuntu, Host/Ubuntu/release, Host/Debian/dpkg-l

Exploit Ease: No known exploits are available

Patch Publication Date: 5/6/2021

Vulnerability Publication Date: 12/7/2020

Reference Information

CVE: CVE-2019-25031, CVE-2019-25032, CVE-2019-25033, 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

USN: 4938-1