Issued:

2017-10-02

Updated:

2017-10-02

RHSA-2017:2836 - Critical: dnsmasq security update

Synopsis

Critical: dnsmasq security update

Type/Severity

Security Advisory Critical

Topic

An update for dnsmasq is now available for Red Hat Enterprise Linux 7.

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)

• A memory exhaustion flaw was found in dnsmasq in the EDNS0 code. An attacker could send crafted DNS packets which would trigger memory allocations which would never be freed, leading to unbounded memory consumption and eventually a crash. This issue only affected configurations using one of the options: add-mac, add-cpe-id, or add-subnet. (CVE-2017-14495)

• An integer underflow flaw leading to a buffer over-read was found in dnsmasq in the EDNS0 code. An attacker could send crafted DNS packets to dnsmasq which would cause it to crash. This issue only affected configurations using one of the options: add-mac, add-cpe-id, or add-subnet. (CVE-2017-14496)

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

Updated Packages

• dnsmasq-2.76-2.el7_4.2.aarch64.rpm
• dnsmasq-debuginfo-2.76-2.el7_4.2.s390x.rpm
• dnsmasq-2.76-2.el7_4.2.ppc64.rpm
• dnsmasq-utils-2.76-2.el7_4.2.x86_64.rpm
• dnsmasq-2.76-2.el7_4.2.s390x.rpm
• dnsmasq-utils-2.76-2.el7_4.2.ppc64le.rpm
• dnsmasq-debuginfo-2.76-2.el7_4.2.ppc64.rpm
• dnsmasq-2.76-2.el7_4.2.ppc64le.rpm
• dnsmasq-2.76-2.el7_4.2.x86_64.rpm
• dnsmasq-2.76-2.el7_4.2.src.rpm
• dnsmasq-utils-2.76-2.el7_4.2.ppc64.rpm
• dnsmasq-debuginfo-2.76-2.el7_4.2.ppc64le.rpm
• dnsmasq-utils-2.76-2.el7_4.2.aarch64.rpm
• dnsmasq-debuginfo-2.76-2.el7_4.2.aarch64.rpm
• dnsmasq-utils-2.76-2.el7_4.2.s390x.rpm
• dnsmasq-debuginfo-2.76-2.el7_4.2.x86_64.rpm

Fixes

• This content is not included.BZ - 1495409
• This content is not included.BZ - 1495410
• This content is not included.BZ - 1495411
• This content is not included.BZ - 1495412
• This content is not included.BZ - 1495415
• This content is not included.BZ - 1495416

CVEs

• CVE-2017-14491
• CVE-2017-14492
• CVE-2017-14493
• CVE-2017-14494
• CVE-2017-14495
• CVE-2017-14496

References

• https://access.redhat.com/security/updates/classification/#critical
• This content is not included.This content is not included.https://access.redhat.com/security/vulnerabilities/3199382

Additional information

• The Red Hat security contact is This content is not included.secalert@redhat.com. More contact details at https://access.redhat.com/security/team/contact/.
• Offline Security Data data is available for integration with other systems. See Offline Security Data API to get started.