GHSA-8FJR-HGHR-4M99

Vulnerability from github – Published: 2023-08-30 20:09 – Updated: 2024-09-13 14:35
VLAI?
Summary
Archive spoofing vulnerability in borgbackup
Details

Impact

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
  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.

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".

Patches

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.

Workarounds

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".

References

https://github.com/borgbackup/borg/blob/1.2.6/docs/changes.rst#pre-125-archives-spoofing-vulnerability-cve-2023-36811

Severity ?
4.7 (Medium)
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N
6.0 (Medium)
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
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{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "borgbackup"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.2.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2023-36811"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-347"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2023-08-30T20:09:33Z",
    "nvd_published_at": "2023-08-30T18:15:09Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\nA flaw in the cryptographic authentication scheme in borgbackup allowed an attacker to fake archives and potentially indirectly cause backup data loss in the repository.\n\nThe attack requires an attacker to be able to\n\n1. insert files (with no additional headers) into backups\n2. gain write access to the repository\n\nThis vulnerability does not disclose plaintext to the attacker, nor does it affect the authenticity of existing archives.\n\nCreating plausible fake archives may be feasible for empty or small archives, but is unlikely for large archives.\n\nAffected are all borgbackup releases prior to 1.2.5.\n\nNote: CVSS scoring model seemed to badly fit for this case, thus I manually set score to \"moderate\".\n\n### Patches\nThe issue has been fixed in borgbackup 1.2.5.\nBut 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.\n\nAdditionally to installing the fixed code, users must follow the upgrade procedure as documented in the latest version of the change log.\n\n### Workarounds\nData 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\".\n\n### References\n\nhttps://github.com/borgbackup/borg/blob/1.2.6/docs/changes.rst#pre-125-archives-spoofing-vulnerability-cve-2023-36811\n",
  "id": "GHSA-8fjr-hghr-4m99",
  "modified": "2024-09-13T14:35:53Z",
  "published": "2023-08-30T20:09:33Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/borgbackup/borg/security/advisories/GHSA-8fjr-hghr-4m99"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-36811"
    },
    {
      "type": "WEB",
      "url": "https://github.com/borgbackup/borg/commit/3eb070191da10c2d3f7bc6484cf3d51c3045f884"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/borgbackup/borg"
    },
    {
      "type": "WEB",
      "url": "https://github.com/borgbackup/borg/blob/1.2.5-cvedocs/docs/changes.rst#pre-125-archives-spoofing-vulnerability-cve-2023-36811"
    },
    {
      "type": "WEB",
      "url": "https://github.com/borgbackup/borg/blob/1.2.6/docs/changes.rst#pre-125-archives-spoofing-vulnerability-cve-2023-36811"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/borgbackup/PYSEC-2023-164.yaml"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/5Q3OHXERTU547SEQ3YREZXHOCYNLVD63"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XOZDFIYEBIOKSIEAXUJJJFUJTAJ7TF3C"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZUCQSMAWOJBCRGF6XPKEZ2TPGAPNKIWV"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Archive spoofing vulnerability in borgbackup"
}


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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.