CVE-2020-25684
Published: 19 January 2021
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.
Priority
Status
| Package | Release | Status |
|---|---|---|
|
dnsmasq Launchpad, Ubuntu, Debian |
bionic |
Released
(2.79-1ubuntu0.2)
|
| hirsute |
Released
(2.82-1ubuntu2)
|
|
| lunar |
Released
(2.82-1ubuntu2)
|
|
| focal |
Released
(2.80-1.1ubuntu1.2)
|
|
| groovy |
Released
(2.82-1ubuntu1.1)
|
|
| impish |
Released
(2.82-1ubuntu2)
|
|
| jammy |
Released
(2.82-1ubuntu2)
|
|
| kinetic |
Released
(2.82-1ubuntu2)
|
|
| trusty |
Needs triage
|
|
| upstream |
Released
(2.83)
|
|
| xenial |
Released
(2.75-1ubuntu0.16.04.7)
|
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 3.7 |
| Attack vector | Network |
| Attack complexity | High |
| Privileges required | None |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality | None |
| Integrity impact | Low |
| Availability impact | None |
| Vector | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N |