FreeBSD : Borg (Backup) -- flaw in cryptographic authentication scheme in Borg allowed an attacker to fake archives and indirectly cause backup data loss. (b8a52e5a-483d-11ee-971d-3df00e0f9020)

medium Nessus Plugin ID 180430



The remote FreeBSD host is missing one or more security-related updates.


The version of FreeBSD installed on the remote host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the b8a52e5a-483d-11ee-971d-3df00e0f9020 advisory.

- borgbackup is an opensource, deduplicating archiver with compression and authenticated encryption. A flaw in the cryptographic authentication scheme in borgbackup allowed an attacker to fake archives and potentially indirectly cause backup data loss in the repository. The attack requires an attacker to be able to: 1. insert files (with no additional headers) into backups and 2. gain write access to the repository. This vulnerability does not disclose plaintext to the attacker, nor does it affect the authenticity of existing archives. Creating plausible fake archives may be feasible for empty or small archives, but is unlikely for large archives. The issue has been fixed in borgbackup 1.2.5. Users are advised to upgrade. Additionally to installing the fixed code, users must follow the upgrade procedure as documented in the change log. Data loss after being attacked can be avoided by reviewing the archives (timestamp and contents valid and as expected) after any borg check --repair and before borg prune.
There are no known workarounds for this vulnerability. (CVE-2023-36811)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.


Update the affected packages.

See Also

Plugin Details

Severity: Medium

ID: 180430

File Name: freebsd_pkg_b8a52e5a483d11ee971d3df00e0f9020.nasl

Version: 1.4

Type: local

Published: 8/31/2023

Updated: 9/25/2023

Risk Information


Risk Factor: Medium

Score: 4.4


Risk Factor: Low

Base Score: 3.8

Temporal Score: 2.8

Vector: CVSS2#AV:L/AC:H/Au:S/C:N/I:C/A:N

CVSS Score Source: CVE-2023-36811


Risk Factor: Medium

Base Score: 4.7

Temporal Score: 4.1

Vector: CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:freebsd:freebsd:py310-borgbackup, p-cpe:/a:freebsd:freebsd:py311-borgbackup, p-cpe:/a:freebsd:freebsd:py312-borgbackup, p-cpe:/a:freebsd:freebsd:py37-borgbackup, p-cpe:/a:freebsd:freebsd:py38-borgbackup, p-cpe:/a:freebsd:freebsd:py39-borgbackup, cpe:/o:freebsd:freebsd

Required KB Items: Host/local_checks_enabled, Host/FreeBSD/release, Host/FreeBSD/pkg_info

Exploit Ease: No known exploits are available

Patch Publication Date: 8/31/2023

Vulnerability Publication Date: 8/30/2023

Reference Information

CVE: CVE-2023-36811