CVE-2023-36811

2023-08-3000:00:00

ubuntu.com

borgbackup

cryptographic authentication

data loss

repository

upgrade

vulnerability

archives

unix

fix

borg check

4.7 Medium

CVSS3

Attack Vector

LOCAL

Attack Complexity

HIGH

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

HIGH

Availability Impact

NONE

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N

0.0004 Low

EPSS

Percentile

15.9%

JSON

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.

OSVersionArchitecturePackageVersionFilename
ubuntu18.04noarchborgbackup< anyUNKNOWN
ubuntu20.04noarchborgbackup< anyUNKNOWN
ubuntu22.04noarchborgbackup< anyUNKNOWN
ubuntu23.10noarchborgbackup< anyUNKNOWN
ubuntu24.04noarchborgbackup< anyUNKNOWN
ubuntu16.04noarchborgbackup< anyUNKNOWN

OS	Version	Architecture	Package	Version	Filename
ubuntu	18.04	noarch	borgbackup	< any	UNKNOWN
ubuntu	20.04	noarch	borgbackup	< any	UNKNOWN
ubuntu	22.04	noarch	borgbackup	< any	UNKNOWN
ubuntu	23.10	noarch	borgbackup	< any	UNKNOWN
ubuntu	24.04	noarch	borgbackup	< any	UNKNOWN
ubuntu	16.04	noarch	borgbackup	< any	UNKNOWN