Security Bypass Affecting dnsmasq package, versions [,2.83)


Severity

Recommended
0.0
low
0
10

CVSS assessment made by Snyk's Security Team. Learn more

Threat Intelligence

EPSS
1.14% (86th percentile)

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  • Snyk IDSNYK-UNMANAGED-DNSMASQ-2335712
  • published12 Jan 2022
  • disclosed20 Jan 2021
  • creditUnknown

Introduced: 20 Jan 2021

CVE-2020-25684  (opens in a new tab)
CWE-358  (opens in a new tab)

How to fix?

Upgrade dnsmasq to version 2.83 or higher.

Overview

Affected versions of this package are vulnerable to Security Bypass. 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.

CVSS Scores

version 3.1