#VU56967 Input validation error in c-ares - CVE-2021-3672

Vulnerability identifier: #VU56967

Vulnerability risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-3672

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
c-ares
Universal components / Libraries / Libraries used by multiple products

Vendor: c-ares.haxx.se

Description

The vulnerability allows a remote attacker to hijack domains.

The vulnerability exists due to insufficient validation of host names, returned by the DNS server. A remote attacker can pass specially crafted input to the application and perform domain hijacking.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

c-ares: 1.0.0 - 1.17.1

---

External links
https://bugzilla.redhat.com/show_bug.cgi?id=1988342
https://c-ares.haxx.se/adv_20210810.html

---

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.