Vulnerability identifier: #VU8664

Vulnerability risk: Medium

CVSSv3.1: 7.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2017-14495

CWE-ID: CWE-400

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Dnsmasq
Server applications / DNS servers

Vendor: GNU

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to incorrect memory allocation (memory is never freed) in  add_pseudoheader() function when processing DNS queries. A remote unauthenticated attacker can send a specially crafted DNS request to the affected service and cause dnsmasq to consume all available memory.

Successful exploitation of this vulnerability may allow an attacker to perform a denial of service (DoS) attack, but requires that dnsmasq is compiled with --add-mac, --add-cpe-id or --add-subnet option.

Mitigation
Update to version 2.78.

Vulnerable software versions

Dnsmasq: 0.4 - 2.77

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External links
http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2017q4/011771.html
http://security.googleblog.com/2017/10/behind-masq-yet-more-dns-and-dhcp.html

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.