Arch Linux Security Advisory ASA-201710-1
=========================================

Severity: Critical
Date    : 2017-10-02
CVE-ID  : CVE-2017-14491 CVE-2017-14492 CVE-2017-14493 CVE-2017-14494
          CVE-2017-14495 CVE-2017-14496
Package : dnsmasq
Type    : multiple issues
Remote  : Yes
Link    : https://security.archlinux.org/AVG-421

Summary
=======

The package dnsmasq before version 2.78-1 is vulnerable to multiple
issues including arbitrary code execution, denial of service and
information disclosure.

Resolution
==========

Upgrade to 2.78-1.

# pacman -Syu "dnsmasq>=2.78-1"

The problems have been fixed upstream in version 2.78.

Workaround
==========

None.

Description
===========

- CVE-2017-14491 (arbitrary code execution)

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-2017-14492 (arbitrary code execution)

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-2017-14493 (arbitrary code execution)

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-2017-14494 (information disclosure)

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-2017-14495 (denial of service)

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-2017-14496 (denial of service)

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.

Impact
======

A remote attacker is able to execute arbitrary code, disclose sensitive
information or crash the application by sending specially crafted
packets.

References
==========

https://security.googleblog.com/2017/10/behind-masq-yet-more-dns-and-dhcp.html
https://github.com/google/security-research-pocs/tree/master/vulnerabilities/dnsmasq
http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commitdiff;h=0549c73b7ea6b22a3c49beb4d432f185a81efcbc
http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commitdiff;h=62cb936cb7ad5f219715515ae7d32dd281a5aa1f
http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commitdiff;h=24036ea507862c7b7898b68289c8130f85599c10
http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commitdiff;h=3d4ff1ba8419546490b464418223132529514033
http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commitdiff;h=33e3f1029c9ec6c63e430ff51063a6301d4b2262
http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commitdiff;h=51eadb692a5123b9838e5a68ecace3ac579a3a45
http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commitdiff;h=897c113fda0886a28a986cc6ba17bb93bd6cb1c7
https://security.archlinux.org/CVE-2017-14491
https://security.archlinux.org/CVE-2017-14492
https://security.archlinux.org/CVE-2017-14493
https://security.archlinux.org/CVE-2017-14494
https://security.archlinux.org/CVE-2017-14495
https://security.archlinux.org/CVE-2017-14496