CVE-2020-25686

low

Description

A flaw was found in dnsmasq before version 2.83. When receiving a query, dnsmasq does not check for an existing pending request for the same name and forwards a new request. By default, a maximum of 150 pending queries can be sent to upstream servers, so there can be at most 150 queries for the same name. This flaw allows an off-path attacker on the network to substantially reduce the number of attempts that it would have to perform to forge a reply and have it accepted by dnsmasq. This issue is mentioned in the "Birthday Attacks" section of RFC5452. If chained with CVE-2020-25684, the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity.

References

https://www.jsof-tech.com/disclosures/dnspooq/

https://bugzilla.redhat.com/show_bug.cgi?id=1890125

https://lists.fedoraproject.org/archives/list/[email protected]/message/WYW3IR6APUSKOYKL5FT3ACTIHWHGQY32/

https://security.gentoo.org/glsa/202101-17

https://www.debian.org/security/2021/dsa-4844

https://lists.fedoraproject.org/archives/list/[email protected]/message/QGB7HL3OWHTLEPSMLDGOMXQKG3KM2QME/

https://www.arista.com/en/support/advisories-notices/security-advisories/12135-security-advisory-61

Details

Source: MITRE

Published: 2021-01-20

Updated: 2022-02-14

Type: CWE-358

Risk Information

CVSS v2

Base Score: 4.3

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

Impact Score: 2.9

Exploitability Score: 8.6

Severity: MEDIUM

CVSS v3

Base Score: 3.7

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

Impact Score: 1.4

Exploitability Score: 2.2

Severity: LOW