[KEV] Privilege Escalation in MinIO (CVE-2023-28434)
Summary
Vulnerability in MinIO (CVE-2023-28434). Risk of unauthorized operations or information disclosure. Exploitable via PostPolicyBucket. Listed in CISA KEV — actively exploited.
Original description
The description as published by the source.
Impact
An attacker can use crafted requests to bypass metadata bucket name checking and put an object into any bucket while processing PostPolicyBucket. To carry out this attack, the attacker requires credentials with arn:aws:s3:::* permission, as well as enabled Console API access.
Patches
commit 67f4ba154a27a1b06e48bfabda38355a010dfca5
Author: Aditya Manthramurthy
Date: Sun Mar 19 21:15:20 2023 -0700
fix: post policy request security bypass (#16849)
Workarounds
Browser API access must be enabled turning off MINIO_BROWSER=off allows for this workaround.
References
The vulnerable code:
// minio/cmd/generic-handlers.go
func setRequestValidityHandler(h http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
// ...
// For all other requests reject access to reserved buckets
bucketName, _ := request2BucketObjectName(r)
if isMinioReservedBucket(bucketName) || isMinioMetaBucket(bucketName) {
if !guessIsRPCReq(r) && !guessIsBrowserReq(r) && !guessIsHealthCheckReq(r) && !guessIsMetricsReq(r) && !isAdminReq(r) && !isKMSReq(r) {
if ok {
tc.FuncName = "handler.ValidRequest"
tc.ResponseRecorder.LogErrBody = true
}
writeErrorResponse(r.Context(), w, errorCodes.ToAPIErr(ErrAllAccessDisabled), r.URL)
return
}
}
// ...
Source: CISA Known Exploited Vulnerabilities NVD GitHub Advisory CISA KEV
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2023-28434 has been found in MinIO.
Attackers can target a specific entry point like PostPolicyBucket over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
Note: CISA has officially confirmed this is actively exploited in the wild. Treat it with elevated urgency.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "MinIO CVE-2023-28434" on the vendor's site.
CVE-2023-28434 (MinIO) — CWE-269
Attack surface: PostPolicyBucket
Listed in CISA KEV — actively exploited, treat as top priority.
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-269) exists in MinIO. Attackers reach the vulnerable code path via PostPolicyBucket.
Check the vendor advisory for the affected versions of MinIO. Attack surface: PostPolicyBucket.
Severity: High. Risk of unauthorized operations or information disclosure. Listed in CISA KEV — actively exploited in the wild, treat as top priority.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'MinIO' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'MinIO' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
MinIOを grep し、稼働しているサービス・バージョンを把握する。 -
2Consider incident declaration escalate
Notify SOC / on-callCISA KEV登録済 = 実環境で悪用が観測されている。侵入の兆候があればインシデント対応宣言、無くてもパッチ適用までWAF強化を最優先で。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com
- web cisa.gov