#VU85406 Heap-based buffer overflow in libspf2 - CVE-2021-33912

Vulnerability identifier: #VU85406

Vulnerability risk: High

CVSSv4.0: 7.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2021-33912

CWE-ID: CWE-122

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
libspf2
Other software / Other software solutions

Vendor: Gnome Development Team

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error within the SPF_record_expand_data() function in spf_expand.c. A remote attacker with control over a DNS server can create a specially crafted SPF DNS record, force the library to read data from the malicious DNS server, trigger a four-byte heap-based buffer overflow and execute arbitrary code on the system.

Mitigation
Cybersecurity Help is currently unaware of any official solution to address this vulnerability.

Vulnerable software versions

libspf2: 1.0.2 - 1.2.10

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External links
https://github.com/shevek/libspf2/tree/8131fe140704eaae695e76b5cd09e39bd1dd220b
https://nathanielbennett.com/blog/libspf2-cve-jan-2022-disclosure
https://lists.debian.org/debian-lts-announce/2022/01/msg00015.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.