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Fencer Intel
medium 5.6

CVE-2020-8911 json

CBC padding oracle in AWS S3 Crypto SDK for GoLang

published 6y ago modified last mo. also GHSA-f5pg-7wfw-84q9 , GO-2022-0646 , EUVD-2022-0971

cvss
5.6
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 28%
public exploits
0
none known

Summary

A padding oracle vulnerability exists in the AWS S3 Crypto SDK for GoLang versions prior to V2. The SDK allows users to encrypt files with AES-CBC without computing a Message Authentication Code (MAC), which then allows an attacker who has write access to the target's S3 bucket and can observe whether or not an endpoint with access to the key can decrypt a file, they can reconstruct the plaintext with (on average) 128*length (plaintext) queries to the endpoint, by exploiting CBC's ability to manipulate the bytes of the next block and PKCS5 padding errors. It is recommended to update your SDK to V2 or later, and re-encrypt your files.

Patch / fix

  • go github.com/aws/aws-sdk-go 1.34.0
  • amazon aws_s3_crypto_sdk 2.0
  • govulncheck-vulndb openSUSE Tumbleweed 0.0.20241119T173509-1.1

opensuse advisories openSUSE-SU-2024:14513-1

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-8911 updated cvss 5.6

aws/aws-sdk-go: CBC padding oracle issue in AWS S3 Crypto SDK for golang

  • Red Hat A-MQ Interconnect 1 amq-ic-1/amq-cert-manager-container Red Hat OpenShift Serverless cli, knative-serving knative-serving, knative-eventing knative-eventing Red Hat Fuse 7 fuse-7/dv-operator-container Red Hat Integration Service Registry rhint-serv-1/integration-service-registry-operator-container
    affected: no fix planned “Will not fix”
  • Red Hat 3Scale AMP 2.11 3scale-amp2/system-rhel7 1.15.0-8, 3scale-amp2/zync-rhel8 3scale2.11.0, 3scale-amp2/backend-rhel8 3scale2.11.0, 3scale-amp2/toolbox-rhel8 3scale2.11.0, 3scale-amp2/memcached-rhel7 3scale2.11.0, 3scale-amp2/3scale-rhel7-operator 3scale2.11.0, +4 more
    fixed: vendor fix RHSA-2021:3851
  • Red Hat OpenShift Service Mesh 1 servicemesh, servicemesh-mixc, servicemesh-mixs, servicemesh-galley, servicemesh-citadel, servicemesh-grafana, +7 more Red Hat Advanced Cluster Management for Kubernetes 2 awk-sdk-go Red Hat Ceph Storage 2 grafana Red Hat Ceph Storage 3 grafana Red Hat Ceph Storage 4 rhceph/rhceph-4-dashboard-rhel8 Red Hat Cluster Application Migration rhmtc/openshift-migration-velero-rhel8, rhmtc/openshift-migration-registry-rhel8, rhmtc/openshift-migration-controller-rhel8, rhmtc/openshift-migration-velero-plugin-for-aws-rhel8, rhmtc/openshift-migration-velero-restic-restore-helper-rhel8
    +5 more products
    Red Hat OpenShift AI (RHOAI) rhoai/odh-mod-arch-gen-ai-rhel9, rhoai/odh-model-controller-rhel9, rhoai/odh-kserve-controller-rhel9, rhoai/odh-kserve-llmisvc-controller-rhel9, rhoai/odh-trustyai-service-operator-rhel9 Red Hat OpenShift Container Platform 3.11 prometheus, atomic-openshift, openshift3/grafana, atomic-openshift-pod, atomic-openshift-node, atomic-openshift-tests, +11 more Red Hat OpenShift Container Platform 4 openshift, openshift-clients, openshift-kubelet, openshift4/ose-cli, openshift-hyperkube, openshift4/ose-grafana, +24 more Red Hat Openshift Container Storage 4 mcg, ocs4/mcg-rhel8-operator, ocs4/rook-ceph-rhel8-operator Red Hat Storage 3 grafana, noobaa-operator-container, multi-cloud-object-gateway-cli, rhgs3/rhgs-gluster-block-prov-rhel7
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.35% chance of exploitation in the next 30 days, higher than 28% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/google/security-research/security/advisories/GHSA-f5pg-7wfw-84q9 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.6 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N
NVD 3.1 5.6 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N
NVD 2.0 2.1 AV:L/AC:L/Au:N/C:P/I:N/A:N
GitHub 3.1 5.6 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
go github.com/aws/aws-sdk-go
<1.34.0
all versions
1.34.0

Affected products

  • Google LLC AWS S3 Crypto SDK for GoLang

Classification

Weakness
  • CWE-327 Use of a Broken or Risky Cryptographic Algorithm

References

Sources

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