Authentication Bypass by Spoofing
CVE-2020-25686
Summary
A flaw was found in dnsmasq prior to 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.
- HIGH
- NETWORK
- LOW
- UNCHANGED
- NONE
- NONE
- NONE
- NONE
CWE-290 - Authentication Bypass by Spoofing
This attack-focused weakness is caused by improperly implemented authentication schemes that are subject to spoofing attacks.
References
Advisory Timeline
- Published