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
EPSS
Percentile
17.7%
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
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.
Affected are all borgbackup releases prior to 1.2.5.
Note: CVSS scoring model seemed to badly fit for this case, thus I manually set score to “moderate”.
The issue has been fixed in borgbackup 1.2.5.
But there was a bug in 1.2.5 upgrade instructions, thus 1.2.6 with an important fix in docs and code was released a day afterwards.
Additionally to installing the fixed code, users must follow the upgrade procedure as documented in the latest version of 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”.
Vendor | Product | Version | CPE |
---|---|---|---|
borgbackup | borg | * | cpe:2.3:a:borgbackup:borg:*:*:*:*:*:*:*:* |
github.com/advisories/GHSA-8fjr-hghr-4m99
github.com/borgbackup/borg/blob/1.2.5-cvedocs/docs/changes.rst#pre-125-archives-spoofing-vulnerability-cve-2023-36811
github.com/borgbackup/borg/blob/1.2.6/docs/changes.rst#pre-125-archives-spoofing-vulnerability-cve-2023-36811
github.com/borgbackup/borg/commit/3eb070191da10c2d3f7bc6484cf3d51c3045f884
github.com/borgbackup/borg/security/advisories/GHSA-8fjr-hghr-4m99
github.com/pypa/advisory-database/tree/main/vulns/borgbackup/PYSEC-2023-164.yaml
lists.fedoraproject.org/archives/list/[email protected]/message/5Q3OHXERTU547SEQ3YREZXHOCYNLVD63
lists.fedoraproject.org/archives/list/[email protected]/message/XOZDFIYEBIOKSIEAXUJJJFUJTAJ7TF3C
lists.fedoraproject.org/archives/list/[email protected]/message/ZUCQSMAWOJBCRGF6XPKEZ2TPGAPNKIWV
nvd.nist.gov/vuln/detail/CVE-2023-36811