CVE-2024-36403

Matrix Media Repo (MMR) is a highly configurable multi-homeserver media repository for Matrix. MMR before version 1.3.5 is vulnerable to unbounded disk consumption, where an unauthenticated adversary can induce it to download and cache large amounts of remote media files. MMR's typical operating environment uses S3-like storage as a backend, with file-backed store as an alternative option. Instances using a file-backed store or those which self-host an S3 storage system are therefore vulnerable to a disk fill attack. Once the disk is full, authenticated users will be unable to upload new media, resulting in denial of service. For instances configured to use a cloud-based S3 storage option, this could result in high service fees instead of a denial of service. MMR 1.3.5 introduces a new default-on "leaky bucket" rate limit to reduce the amount of data a user can request at a time. This does not fully address the issue, but does limit an unauthenticated user's ability to request large amounts of data. Operators should note that the leaky bucket implementation introduced in MMR 1.3.5 requires the IP address associated with the request to be forwarded, to avoid mistakenly applying the rate limit to the reverse proxy instead. To avoid this issue, the reverse proxy should populate the X-Forwarded-For header when sending the request to MMR. Operators who cannot update may wish to lower the maximum file size they allow and implement harsh rate limits, though this can still lead to a large amount of data to be downloaded.

Matrix Media Repo (MMR) is a highly configurable multi-homeserver media repository for Matrix. MMR before version 1.3.5 is vulnerable to unbounded disk consumption, where an unauthenticated adversary can induce it to download and cache large amounts of remote media files. MMR's typical operating environment uses S3-like storage as a backend, with file-backed store as an alternative option. Instances using a file-backed store or those which self-host an S3 storage system are therefore vulnerable to a disk fill attack. Once the disk is full, authenticated users will be unable to upload new media, resulting in denial of service. For instances configured to use a cloud-based S3 storage option, this could result in high service fees instead of a denial of service. MMR 1.3.5 introduces a new default-on "leaky bucket" rate limit to reduce the amount of data a user can request at a time. This does not fully address the issue, but does limit an unauthenticated user's ability to request large amounts of data. Operators should note that the leaky bucket implementation introduced in MMR 1.3.5 requires the IP address associated with the request to be forwarded, to avoid mistakenly applying the rate limit to the reverse proxy instead. To avoid this issue, the reverse proxy should populate the X-Forwarded-For header when sending the request to MMR. Operators who cannot update may wish to lower the maximum file size they allow and implement harsh rate limits, though this can still lead to a large amount of data to be downloaded.

Impact

MMR before version 1.3.5 is vulnerable to unbounded disk consumption, where an unauthenticated adversary can induce it to download and cache large amounts of remote media files.

MMR's typical operating environment uses S3-like storage as a backend, with file-backed store as an alternative option. Instances using a file-backed store or those which self-host an S3 storage system are therefore vulnerable to a disk fill attack. Once the disk is full, authenticated users will be unable to upload new media, resulting in denial of service.

For instances configured to use a cloud-based S3 storage option, this could result in high service fees instead of a denial of service.

Patches

MMR 1.3.5 introduces a new default-on "leaky bucket" rate limit to reduce the amount of data a user can request at a time. This does not fully address the issue, but does limit an unauthenticated user's ability to request large amounts of data.

Operators should note that the leaky bucket implementation introduced in MMR 1.3.5 requires the IP address associated with the request to be forwarded, to avoid mistakenly applying the rate limit to the reverse proxy instead. To avoid this issue, the reverse proxy should populate the X-Forwarded-For header when sending the request to MMR.

Workarounds

Operators may wish to lower the maximum file size they allow and implement harsh rate limits, though this can still lead to a large amount of data to be downloaded.

References

https://en.wikipedia.org/wiki/Leaky_bucket#As_a_meter

Matrix Media Repo (MMR) is a highly configurable multi-homeserver media repository for Matrix. MMR before version 1.3.5 is vulnerable to unbounded disk consumption, where an unauthenticated adversary can induce it to download and cache large amounts of remote media files. MMR's typical operating environment uses S3-like storage as a backend, with file-backed store as an alternative option. Instances using a file-backed store or those which self-host an S3 storage system are therefore vulnerable to a disk fill attack. Once the disk is full, authenticated users will be unable to upload new media, resulting in denial of service. For instances configured to use a cloud-based S3 storage option, this could result in high service fees instead of a denial of service. MMR 1.3.5 introduces a new default-on "leaky bucket" rate limit to reduce the amount of data a user can request at a time. This does not fully address the issue, but does limit an unauthenticated user's ability to request large amounts of data. Operators should note that the leaky bucket implementation introduced in MMR 1.3.5 requires the IP address associated with the request to be forwarded, to avoid mistakenly applying the rate limit to the reverse proxy instead. To avoid this issue, the reverse proxy should populate the X-Forwarded-For header when sending the request to MMR. Operators who cannot update may wish to lower the maximum file size they allow and implement harsh rate limits, though this can still lead to a large amount of data to be downloaded.

Matrix Media Repo (MMR) is a highly configurable multi-homeserver media repository for Matrix. MMR before version 1.3.5 is vulnerable to unbounded disk consumption, where an unauthenticated adversary can induce it to download and cache large amounts of remote media files. MMR's typical operating environment uses S3-like storage as a backend, with file-backed store as an alternative option. Instances using a file-backed store or those which self-host an S3 storage system are therefore vulnerable to a disk fill attack. Once the disk is full, authenticated users will be unable to upload new media, resulting in denial of service. For instances configured to use a cloud-based S3 storage option, this could result in high service fees instead of a denial of service. MMR 1.3.5 introduces a new default-on "leaky bucket" rate limit to reduce the amount of data a user can request at a time. This does not fully address the issue, but does limit an unauthenticated user's ability to request large amounts of data. Operators should note that the leaky bucket implementation introduced in MMR 1.3.5 requires the IP address associated with the request to be forwarded, to avoid mistakenly applying the rate limit to the reverse proxy instead. To avoid this issue, the reverse proxy should populate the X-Forwarded-For header when sending the request to MMR. Operators who cannot update may wish to lower the maximum file size they allow and implement harsh rate limits, though this can still lead to a large amount of data to be downloaded.

Impact

MMR before version 1.3.5 is vulnerable to unbounded disk consumption, where an unauthenticated adversary can induce it to download and cache large amounts of remote media files.

MMR's typical operating environment uses S3-like storage as a backend, with file-backed store as an alternative option. Instances using a file-backed store or those which self-host an S3 storage system are therefore vulnerable to a disk fill attack. Once the disk is full, authenticated users will be unable to upload new media, resulting in denial of service.

For instances configured to use a cloud-based S3 storage option, this could result in high service fees instead of a denial of service.

Patches

MMR 1.3.5 introduces a new default-on "leaky bucket" rate limit to reduce the amount of data a user can request at a time. This does not fully address the issue, but does limit an unauthenticated user's ability to request large amounts of data.

Operators should note that the leaky bucket implementation introduced in MMR 1.3.5 requires the IP address associated with the request to be forwarded, to avoid mistakenly applying the rate limit to the reverse proxy instead. To avoid this issue, the reverse proxy should populate the X-Forwarded-For header when sending the request to MMR.

Workarounds

Operators may wish to lower the maximum file size they allow and implement harsh rate limits, though this can still lead to a large amount of data to be downloaded.

References

https://en.wikipedia.org/wiki/Leaky_bucket#As_a_meter

matrix-media-repo (MMR) allows denial of service/high operating costs through unauthenticated downloads in github.com/t2bot/matrix-media-repo

These are all security issues fixed in the govulncheck-vulndb-0.0.20250117T214834-1.1 package on the GA media of openSUSE Tumbleweed.

This update for govulncheck-vulndb fixes the following issues:

• Update to version 0.0.20250128T150132 2025-01-28T15:01:32Z. Refs jsc#PED-11136 Go CVE Numbering Authority IDs added or updated with aliases:

  • GO-2025-3409 CVE-2025-23208 GHSA-c9p4-xwr9-rfhx
  • GO-2025-3410 CVE-2025-24337 GHSA-3qc3-mx6x-267h
  • GO-2025-3413 CVE-2025-0377 GHSA-wpfp-cm49-9m9q
  • GO-2025-3414 CVE-2024-11218 GHSA-5vpc-35f4-r8w6
  • GO-2025-3415 CVE-2025-23028 GHSA-9m5p-c77c-f9j7
  • GO-2025-3416 CVE-2025-23047 GHSA-h78m-j95m-5356
  • GO-2025-3418 CVE-2025-24030 GHSA-j777-63hf-hx76
  • GO-2025-3419 CVE-2025-24355 GHSA-v34r-vj4r-38j6
  • GO-2025-3422 CVE-2025-24354

• Update to version 0.0.20250128T004730 2025-01-28T00:47:30Z. Refs jsc#PED-11136 Go CVE Numbering Authority IDs added or updated with aliases:

  • GO-2025-3372 CVE-2024-45339
  • GO-2025-3373 CVE-2024-45341
  • GO-2025-3383 CVE-2024-45340
  • GO-2025-3420 CVE-2024-45336
  • GO-2025-3421 CVE-2025-22865

• Update to version 0.0.20250117T214834 2025-01-17T21:48:34Z. Refs jsc#PED-11136 Go CVE Numbering Authority IDs added or updated with aliases:

  • GO-2025-3392 CVE-2025-20086 GHSA-5m7j-6gc4-ff5g
  • GO-2025-3393 CVE-2025-21088 GHSA-8j3q-gc9x-7972
  • GO-2025-3394 CVE-2025-20088 GHSA-45v9-w9fh-33j6
  • GO-2025-3396 CVE-2024-52594
  • GO-2025-3397 CVE-2024-36402 GHSA-8vmr-h7h5-cqhg
  • GO-2025-3398 CVE-2024-52791 GHSA-gp86-q8hg-fpxj
  • GO-2025-3399 CVE-2024-52602 GHSA-r6jg-jfv6-2fjv
  • GO-2025-3400 CVE-2024-56515 GHSA-rcxc-wjgw-579r
  • GO-2025-3401 CVE-2024-36403 GHSA-vc2m-hw89-qjxf
  • GO-2025-3407 CVE-2025-20621 GHSA-w6xh-c82w-h997

• Update to version 0.0.20250115T172141 2025-01-15T17:21:41Z. Refs jsc#PED-11136 Go CVE Numbering Authority IDs added or updated with aliases:

  • GO-2025-3381 CVE-2024-56138 GHSA-45v3-38pc-874v
  • GO-2025-3382 CVE-2024-51491 GHSA-qjh3-4j3h-vmwp
  • GO-2025-3384 CVE-2024-56323 GHSA-32q6-rr98-cjqv
  • GO-2025-3390 CVE-2024-53263 GHSA-q6r2-x2cc-vrp7
  • GO-2025-3391 CVE-2024-52281 GHSA-2v2w-8v8c-wcm9

• Update to version 0.0.20250109T194159 2025-01-09T19:41:59Z. Refs jsc#PED-11136 Go CVE Numbering Authority IDs added or updated with aliases:

  • GO-2025-3376 CVE-2025-22149 GHSA-675f-rq2r-jw82
  • GO-2025-3377 CVE-2025-22449 GHSA-q8fg-cp3q-5jwm
  • GO-2025-3379 CVE-2025-20033 GHSA-2549-xh72-qrpm
  • GO-2025-3380 CVE-2025-22445 GHSA-7rgp-4j56-fm79