CVE-2021-25633: Content Manipulation with Double Certificate Attack
First published: Mon Oct 11 2021(Updated: )
LibreOffice supports digital signatures of ODF documents and macros within documents, presenting visual aids that no alteration of the document occurred since the last signing and that the signature is valid. An Improper Certificate Validation vulnerability in LibreOffice allowed an attacker to create a digitally signed ODF document, by manipulating the documentsignatures.xml or macrosignatures.xml stream within the document to combine multiple certificate data, which when opened caused LibreOffice to display a validly signed indicator but whose content was unrelated to the signature shown. This issue affects: The Document Foundation LibreOffice 7-0 versions prior to 7.0.6; 7-1 versions prior to 7.1.2.
Credit: security@documentfoundation.org
| Affected Software | Affected Version | How to fix |
|---|---|---|
| debian/libreoffice | <=1:6.1.5-3+deb10u7<=1:6.1.5-3+deb10u10 | 1:7.0.4-4+deb11u7 4:7.4.7-1 4:7.5.6-1 4:7.5.8~rc1-1 |
| The Document Foundation LibreOffice | >=7.0.0<7.0.6 | |
| The Document Foundation LibreOffice | >=7.1.0<7.1.2 | |
| Debian Debian Linux | =11.0 |
Remedy
Update to 7.0.6 or 7.1.2 or 7.2.0
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Reference Links
- https://www.libreoffice.org/about-us/security/advisories/CVE-2021-25633
- https://www.openwall.com/lists/oss-security/2021/10/11/1
- https://github.com/LibreOffice/core/commit/ad5930e87e788780a255523f106deb1dde5d7b37
- https://github.com/LibreOffice/core/commit/d92235df75829a8cf2ee8cc7b0b76063093b6cc2
- https://github.com/LibreOffice/core/commit/a1cf770c2d7ca3e153e0b1f01ddcc313bc2bed7f
- https://github.com/LibreOffice/core/commit/be773bc5960def8c51de0e0e41db837e001aa8fd
- https://security-tracker.debian.org/tracker/CVE-2021-25633
- https://www.debian.org/security/2021/dsa-4988
Frequently Asked Questions
What is CVE-2021-25633?
CVE-2021-25633 is an Improper Certificate Validation vulnerability in LibreOffice that allowed an attacker to create malicious digital signatures and bypass document integrity checks.
How does LibreOffice support digital signatures?
LibreOffice supports digital signatures of ODF documents and macros within documents, providing visual aids to show that no alteration of the document occurred since the last signing and that the signature is valid.
What is the severity of CVE-2021-25633?
The severity of CVE-2021-25633 is high, with a severity value of 7.5.
Which versions of LibreOffice are affected by CVE-2021-25633?
LibreOffice versions 1:6.1.5-3+deb10u7 to 1:6.1.5-3+deb10u10, 7.0.0 to 7.0.6, and 7.1.0 to 7.1.2 are affected by CVE-2021-25633.
How can I fix CVE-2021-25633?
To fix CVE-2021-25633, users should update to LibreOffice versions 1:7.0.4-4+deb11u7, 4:7.4.7-1, 4:7.5.6-1, or 4:7.5.8~rc1-1.
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