USN-4698-1: Dnsmasq vulnerabilities

19 January 2021

Several security issues were fixed in Dnsmasq.

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Releases

Packages

  • dnsmasq - Small caching DNS proxy and DHCP/TFTP server

Details

Moshe Kol and Shlomi Oberman discovered that Dnsmasq incorrectly handled
memory when sorting RRsets. A remote attacker could use this issue to cause
Dnsmasq to hang, resulting in a denial of service, or possibly execute
arbitrary code. (CVE-2020-25681, CVE-2020-25687)

Moshe Kol and Shlomi Oberman discovered that Dnsmasq incorrectly handled
extracting certain names. A remote attacker could use this issue to cause
Dnsmasq to hang, resulting in a denial of service, or possibly execute
arbitrary code. (CVE-2020-25682, CVE-2020-25683)

Moshe Kol and Shlomi Oberman discovered that Dnsmasq incorrectly
implemented address/port checks. A remote attacker could use this issue to
perform a cache poisoning attack. (CVE-2020-25684)

Moshe Kol and Shlomi Oberman discovered that Dnsmasq incorrectly
implemented query resource name checks. A remote attacker could use this
issue to perform a cache poisoning attack. (CVE-2020-25685)

Moshe Kol and Shlomi Oberman discovered that Dnsmasq incorrectly handled
multiple query requests for the same resource name. A remote attacker could
use this issue to perform a cache poisoning attack. (CVE-2020-25686)

It was discovered that Dnsmasq incorrectly handled memory during DHCP
response creation. A remote attacker could possibly use this issue to
cause Dnsmasq to consume resources, leading to a denial of service. This
issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 20.04
LTS. (CVE-2019-14834)

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Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines.

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Update instructions

The problem can be corrected by updating your system to the following package versions:

Ubuntu 20.10
Ubuntu 20.04
Ubuntu 18.04
Ubuntu 16.04

After a standard system update you need to reboot your computer to make
all the necessary changes.

References

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Further reading