#VU76669 Integer underflow in MaraDNS - CVE-2023-31137

Vulnerability identifier: #VU76669

Vulnerability risk: Medium

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:Green]

CVE-ID: CVE-2023-31137

CWE-ID: CWE-191

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
MaraDNS
Server applications / DNS servers

Vendor: Sam Trenholme

Description

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

The vulnerability exists due to integer underflow when handling a DNS packet with an Answer RR of qtype 16 (TXT record) and any qclass. A remote attacker can send a specially crafted request to the server, trigger an integer underflow and perform a denial of service (DoS) attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

MaraDNS: 3.2.06 - 3.5.0023

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External links
https://github.com/samboy/MaraDNS/security/advisories/GHSA-58m7-826v-9c3c
https://github.com/samboy/MaraDNS/commit/bab062bde40b2ae8a91eecd522e84d8b993bab58
https://github.com/samboy/MaraDNS/blob/08b21ea20d80cedcb74aa8f14979ec7c61846663/dns/Decompress.c#L886
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NB7LDZM5AGWC5BHHQHW6CP5OFNBBKFOQ/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3VSMLJX25MXGQ6A7UPOGK7VPUVDESPHL/

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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.