Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

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CVE-2020-25686

Severity CVSS v4.0:
Pending analysis
Type:
Unavailable / Other
Publication date:
20/01/2021
Last modified:
07/11/2023

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.

Impact

Vector 3.x
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N CVSS v3.1 Severity and Metrics:

Base Score: 3.70 LOW
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

Attack Vector (AV): Network
Attack Complexity (AC): High
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): None
Integrity (I): Low
Availability (A): None

Base Score 3.x
3.70
Severity 3.x
LOW
Vector 2.0
AV:N/AC:M/Au:N/C:N/I:P/A:N CVSS v2.0 Severity and Metrics:

Base Score: 4.30 MEDIUM
Vector: AV:N/AC:M/Au:N/C:N/I:P/A:N

Attack Vector (AV): Network
Attack Complexity (AC): Medium
Authentication (Au): None
Confidentiality (C): None
Integrity (I): Physical
Availability (A): None

Base Score 2.0
4.30
Severity 2.0
MEDIUM

Vulnerable products and versions

CPE From Up to
cpe:2.3:a:thekelleys:dnsmasq:*:*:*:*:*:*:*:* 2.83 (excluding)
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
cpe:2.3:o:arista:eos:*:*:*:*:*:*:*:* 4.21 (including) 4.21.14m (excluding)
cpe:2.3:o:arista:eos:*:*:*:*:*:*:*:* 4.22 (including) 4.22.9m (excluding)
cpe:2.3:o:arista:eos:*:*:*:*:*:*:*:* 4.23 (including) 4.23.7m (excluding)
cpe:2.3:o:arista:eos:*:*:*:*:*:*:*:* 4.24 (including) 4.24.5m (excluding)
cpe:2.3:o:arista:eos:*:*:*:*:*:*:*:* 4.25 (including) 4.25.2f (excluding)

To consult the complete list of CPE names with products and versions, see this page


References to Advisories, Solutions, and Tools