GLSA 202105-20: Dnsmasq: DNS cache poisoning

http://security.gentoo.org/

Severity:	low
Title:	Dnsmasq: DNS cache poisoning
Date:	05/26/2021
Bugs:	#782130
ID:	202105-20

Synopsis

Use of insufficient randomness in Dnsmasq might lead to DNS Cache Poisoning.

Background

Dnsmasq is a lightweight and easily-configurable DNS forwarder and DHCP server.

Affected packages

Package	Vulnerable	Unaffected	Architecture(s)
net-dns/dnsmasq	< 2.85	>= 2.85	All supported architectures

Description

It was discovered that Dnsmasq, when configured with --server=<address>@ or similar (e.g. through dbus), configured a fixed UDP port for all outgoing queries to the specified upstream DNS server.

Impact

An attacker, by sending malicious crafted DNS responses, could perform a DNS Cache Poisoning attack.

Workaround

There is no known workaround at this time.

Resolution

All Dnsmasq users should upgrade to the latest version:

      # emerge --sync
      # emerge --ask --oneshot --verbose ">=net-dns/dnsmasq-2.85"

References

CVE-2021-3448

Availability

This GLSA and any updates to it are available for viewing at the Gentoo Security Website: http://security.gentoo.org/glsa/glsa-202105-20.xml

Concerns?

Security is a primary focus of Gentoo Linux and ensuring the confidentiality and security of our users machines is of utmost importance to us. Any security concerns should be addressed to security@gentoo.org or alternatively, you may file a bug at https://bugs.gentoo.org.