#VU17349 Input validation error in Avahi - CVE-2017-6519

Vulnerability identifier: #VU17349

Vulnerability risk: Low

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2017-6519

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Avahi
Universal components / Libraries / Libraries used by multiple products

Vendor: avahi.org

Description

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

The vulnerability exists due to avahi-daemon inadvertently responds to IPv6 unicast queries with source addresses that are not on-link. A remote attacker can submit specially crafted port-5353 UDP packet to trigger traffic amplification and cause the service to crash.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Avahi: 0.6.32 - 0.7

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External links
https://github.com/lathiat/avahi/issues/203
https://github.com/lathiat/avahi/issues/203#issuecomment-449536790
https://www.secfu.net/advisories

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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.