Topic

An update for dnsmasq is now available for Red Hat Enterprise Linux 7.2 Extended Update Support and Red Hat Enterprise Linux 7.3 Extended Update Support.

Red Hat Product Security has rated this update as having a security impact of Critical. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Description

The dnsmasq packages contain Dnsmasq, a lightweight DNS (Domain Name Server) forwarder and DHCP (Dynamic Host Configuration Protocol) server.

Security Fix(es):

• A heap buffer overflow was found in dnsmasq in the code responsible for building DNS replies. An attacker could send crafted DNS packets to dnsmasq which would cause it to crash or, potentially, execute arbitrary code. (CVE-2017-14491)
• A heap buffer overflow was discovered in dnsmasq in the IPv6 router advertisement (RA) handling code. An attacker on the local network segment could send crafted RAs to dnsmasq which would cause it to crash or, potentially, execute arbitrary code. This issue only affected configurations using one of these options: enable-ra, ra-only, slaac, ra-names, ra-advrouter, or ra-stateless. (CVE-2017-14492)
• A stack buffer overflow was found in dnsmasq in the DHCPv6 code. An attacker on the local network could send a crafted DHCPv6 request to dnsmasq which would cause it to a crash or, potentially, execute arbitrary code. (CVE-2017-14493)
• An information leak was found in dnsmasq in the DHCPv6 relay code. An attacker on the local network could send crafted DHCPv6 packets to dnsmasq causing it to forward the contents of process memory, potentially leaking sensitive data. (CVE-2017-14494)

Red Hat would like to thank Felix Wilhelm (Google Security Team), Fermin J. Serna (Google Security Team), Gabriel Campana (Google Security Team), Kevin Hamacher (Google Security Team), and Ron Bowes (Google Security Team) for reporting these issues.

Solution

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.3 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.2 x86_64
• Red Hat Enterprise Linux Server - AUS 7.2 x86_64
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.3 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.2 s390x
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.3 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.2 ppc64
• Red Hat Enterprise Linux EUS Compute Node 7.3 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.2 x86_64
• Red Hat Enterprise Linux Server - AUS 7.3 x86_64
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.3 ppc64le
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.2 ppc64le
• Red Hat Enterprise Linux Server - TUS 7.3 x86_64
• Red Hat Enterprise Linux Server - TUS 7.2 x86_64
• Red Hat Enterprise Linux Server (for IBM Power LE) - Update Services for SAP Solutions 7.3 ppc64le
• Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.3 x86_64
• Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.2 x86_64

Fixes

• BZ - 1495409 - CVE-2017-14491 dnsmasq: heap overflow in the code responsible for building DNS replies
• BZ - 1495410 - CVE-2017-14492 dnsmasq: heap overflow in the IPv6 router advertisement code
• BZ - 1495411 - CVE-2017-14493 dnsmasq: stack buffer overflow in the DHCPv6 code
• BZ - 1495412 - CVE-2017-14494 dnsmasq: information leak in the DHCPv6 relay code

CVEs

• CVE-2017-14491
• CVE-2017-14492
• CVE-2017-14493
• CVE-2017-14494

References

• https://access.redhat.com/security/updates/classification/#critical
• https://access.redhat.com/security/vulnerabilities/3199382