title: Archive spoofing vulnerability in borgbackup
description: 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.
problem types: CWE-347: Improper Verification of Cryptographic Signature
affected:
{
vendor: borgbackup
product: borg
versions:
version: < 1.2.5, status: affected
}
metrics:
cvssV3_1: [
attackComplexity: HIGH
attackVector: LOCAL
availabilityImpact: NONE
baseScore: 4.7
baseSeverity: MEDIUM
confidentialityImpact: NONE
integrityImpact: HIGH
privilegesRequired: LOW
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N
version: 3.1
]