CVE-2020-25684
Description
A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query, dnsmasq checks in the forward.c:reply_query() if the reply destination address/port is used by the pending forwarded queries. However, it does not use the address/port to retrieve the exact forwarded query, substantially reducing the number of attempts an attacker on the network would have to perform to forge a reply and get it accepted by dnsmasq. This issue contrasts with RFC5452, which specifies a query's attributes that all must be used to match a reply. This flaw allows an attacker to perform a DNS Cache Poisoning attack. If chained with CVE-2020-25685 or CVE-2020-25686, the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2020-25684
Vendor advisory: suse — https://www.suse.com/security/cve/CVE-2020-25684.html
Vendor advisory: arch — https://security.archlinux.org/ASA-202101-38
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| arch | fixed | 2.83-1 | |
| debian | bookworm | fixed | 2.83-1 |
| debian | bullseye | fixed | 2.83-1 |
| debian | forky | fixed | 2.83-1 |
| debian | sid | fixed | 2.83-1 |
| debian | trixie | fixed | 2.83-1 |
| sles | affected | |
References
Verify integrity in audit chain (admin only). AS-IS.