Ubuntu update for libreoffice

1) Improper certificate validation

EUVDB-ID: #VU60762

Risk: Low

CVSSv4.0: 1 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-25636

CWE-ID: CWE-295 - Improper Certificate Validation

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a spoofing attack.

The vulnerability exists due to improper certificate validation when processing digital signatures of ODF documents. A remote attacker can modify the documentsignatures.xml or macrosignatures.xml stream within the document to contain both "X509Data" and "KeyValue" children of the "KeyInfo" tag[1], which when opened caused LibreOffice to verify using the "KeyValue" but to report verification with the unrelated "X509Data" value.

Mitigation

Update the affected package libreoffice to the latest version.

Vulnerable software versions

Ubuntu: 18.04 - 21.10

libreoffice-core (Ubuntu package): before 1:6.0.7-0ubuntu0.18.04.11

CPE2.3

• cpe:2.3:o:canonical:ubuntu:18.04:*:*:*:*:*:*:*
• cpe:2.3:o:canonical:ubuntu:20.04:*:*:*:*:*:*:*
• cpe:2.3:o:canonical:ubuntu:21.10:*:*:*:*:*:*:*
• cpe:2.3:a:canonical:libreoffice-core_ubuntu_package:*:*:*:*:*:ubuntu:*:*

External links

https://ubuntu.com/security/notices/USN-5330-1

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.