A libreoffice security update has been released for Debian GNU/Linux 10 LTS to address multiple vulnerabilities that may lead to arbitrary script execution, improper certificate validation, and weak encryption
of password storage in the user's configuration database.

DLA 3368-1: libreoffice security update

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Debian LTS Advisory DLA-3368-1 debian-lts@lists.debian.org
  https://www.debian.org/lts/security/ Bastien Roucaries
March 26, 2023   https://wiki.debian.org/LTS
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Package : libreoffice
Version : 1:6.1.5-3+deb10u8
CVE ID : CVE-2021-25636 CVE-2022-3140 CVE-2022-26305 CVE-2022-26306
CVE-2022-26307

Multiple vulnerabilities were found in LibreOffice an
office productivity software suite, leading to arbitrary script
execution, improper certificate validation, and weak encryption
of password storage in the users configuration database.

CVE-2021-25636

Only use X509Data
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 contain both "X509Data" and "KeyValue" children
of the "KeyInfo" tag, which when opened caused LibreOffice to verify
using the "KeyValue" but to report verification with the unrelated
"X509Data" value.

CVE-2022-3140

Insufficient validation of "vnd.libreoffice.command"
URI schemes. LibreOffice supports Office URI Schemes to enable browser
integration of LibreOffice with MS SharePoint server. An additional
scheme 'vnd.libreoffice.command' specific to LibreOffice was added. In
the affected versions of LibreOffice links using that scheme could be
constructed to call internal macros with arbitrary arguments. Which
when clicked on, or activated by document events, could result in
arbitrary script execution without warning.

CVE-2022-26305

Compare authors using Thumbprint
An Improper Certificate Validation vulnerability in LibreOffice
existed where determining if a macro was signed by a trusted author
was done by only matching the serial number and issuer string of the
used certificate with that of a trusted certificate. This is not
sufficient to verify that the macro was actually signed with the
certificate. An adversary could therefore create an arbitrary
certificate with a serial number and an issuer string identical to a
trusted certificate which LibreOffice would present as belonging to
the trusted author, potentially leading to the user to execute
arbitrary code contained in macros improperly trusted.

CVE-2022-26306

LibreOffice supports the storage of passwords for
web connections in the user’s configuration database. The stored
passwords are encrypted with a single master key provided by the
user. A flaw in LibreOffice existed where the required initialization
vector for encryption was always the same which weakens the security
of the encryption making them vulnerable if an attacker has access to
the user's configuration data

CVE-2022-26307

Add Initialization Vectors to password storage.
LibreOffice supports the storage of passwords for web connections in
the user’s configuration database. The stored passwords are encrypted
with a single master key provided by the user. A flaw in LibreOffice
existed where master key was poorly encoded resulting in weakening its
entropy from 128 to 43 bits making the stored passwords vulerable to a
brute force attack if an attacker has access to the users stored
config.

For Debian 10 buster, these problems have been fixed in version
1:6.1.5-3+deb10u8.

We recommend that you upgrade your libreoffice packages.

For the detailed security status of libreoffice please refer to
its security tracker page at:
  https://security-tracker.debian.org/tracker/libreoffice

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at:   https://wiki.debian.org/LTS