CVE-2024-55949: MinIO IAM Privilege Escalation Vulnerability

CVE-2024-55949 Overview

CVE-2024-55949 is a critical privilege escalation vulnerability affecting MinIO, a high-performance, S3-compatible object storage solution distributed under the GNU AGPLv3 license. The vulnerability exists in the IAM (Identity and Access Management) import API, allowing attackers to escalate privileges on affected MinIO deployments. All MinIO installations running code from commit 580d9db85e04f1b63cc2909af50f0ed08afa965f onward are impacted until the security fix is applied.

Critical Impact

This privilege escalation vulnerability affects all MinIO users and has no available workarounds. Immediate upgrade to RELEASE.2024-12-13T22-19-12Z or later is required.

Affected Products

• MinIO Object Storage (all versions from commit 580d9db85e04f1b63cc2909af50f0ed08afa965f)
• MinIO versions prior to RELEASE.2024-12-13T22-19-12Z
• All MinIO deployments utilizing the IAM import API functionality

Discovery Timeline

• December 16, 2024 - CVE-2024-55949 published to NVD
• December 16, 2024 - Last updated in NVD database

Technical Details for CVE-2024-55949

Vulnerability Analysis

The vulnerability resides in MinIO's IAM import API functionality, specifically within the administrative handlers responsible for importing and exporting IAM data. The flaw stems from improper privilege management (CWE-269) during IAM data import operations, enabling network-based attackers to escalate their privileges without requiring authentication or user interaction.

The vulnerability allows high impact to both confidentiality and integrity of the affected system, while availability remains unaffected. This combination is particularly dangerous in enterprise environments where MinIO stores sensitive data, as attackers could gain unauthorized access to protected resources or modify IAM policies to establish persistent access.

Root Cause

The root cause is classified as CWE-269 (Improper Privilege Management). The vulnerability was introduced in commit 580d9db85e04f1b63cc2909af50f0ed08afa965f which added APIs to import/export IAM data. The implementation failed to properly validate authorization requirements when processing IAM import requests.

Analysis of the security patch in cmd/admin-handlers-users.go reveals that the original code did not properly handle cases where the object API validation failed. The fix ensures that when validateAdminReq fails and returns a nil objectAPI, an appropriate error response (ErrServerNotInitialized) is returned instead of continuing execution.

Attack Vector

The attack is network-based and requires no authentication or user interaction, making it highly exploitable. An attacker with network access to a vulnerable MinIO instance can send specially crafted requests to the IAM import API endpoint to escalate privileges.

// Security patch in cmd/admin-handlers-users.go
// fix: Privilege escalation in IAM import API (#20756)
 	// Get current object layer instance.
 	objectAPI, _ := validateAdminReq(ctx, w, r, policy.ExportIAMAction)
 	if objectAPI == nil {
+		writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(ErrServerNotInitialized), r.URL)
 		return
 	}
 	// Initialize a zip writer which will provide a zipped content

Source: GitHub MinIO Commit f246c905

Additional patches were applied to error handling in cmd/admin-handler-utils.go:

// Security patch in cmd/admin-handler-utils.go
// Add APIs to import/export IAM data (#15014)
 	}
 	return toAPIError(ctx, fmt.Errorf("error importing %s from %s with: %w", entity, fname, err))
 }
+
+// wraps import error for more context
+func importErrorWithAPIErr(ctx context.Context, apiErr APIErrorCode, err error, fname, entity string) APIError {
+	if entity == "" {
+		return errorCodes.ToAPIErrWithErr(apiErr, fmt.Errorf("error importing %s with: %w", fname, err))
+	}
+	return errorCodes.ToAPIErrWithErr(apiErr, fmt.Errorf("error importing %s from %s with: %w", entity, fname, err))
+}

Source: GitHub MinIO Commit 580d9db8

Detection Methods for CVE-2024-55949

Indicators of Compromise

• Unexpected modifications to IAM policies or user permissions in MinIO
• Unusual API requests to the /minio/admin/v3/import-iam endpoint
• Creation of new administrative users or policies without authorized changes
• Anomalous access patterns to S3 buckets that were previously restricted

Detection Strategies

• Monitor MinIO administrative API endpoints for unauthorized access attempts
• Review MinIO audit logs for IAM import/export operations from unexpected sources
• Implement network-level monitoring for traffic to MinIO admin API ports
• Deploy SentinelOne agents on MinIO hosts to detect privilege escalation behaviors

Monitoring Recommendations

• Enable comprehensive audit logging in MinIO configurations
• Set up alerts for any IAM policy modifications or administrative actions
• Monitor for unauthorized network connections to MinIO services
• Regularly review and audit IAM configurations for unexpected changes

How to Mitigate CVE-2024-55949

Immediate Actions Required

• Upgrade MinIO immediately to RELEASE.2024-12-13T22-19-12Z or later
• Audit existing IAM policies and user accounts for unauthorized modifications
• Review access logs for any suspicious IAM import operations
• Restrict network access to MinIO administrative endpoints while upgrade is planned

Patch Information

The vulnerability has been addressed in MinIO commit f246c9053f9603e610d98439799bdd2a6b293427, which is included in release RELEASE.2024-12-13T22-19-12Z. Organizations should upgrade to this release or later immediately. For detailed information, refer to the GitHub Security Advisory GHSA-cwq8-g58r-32hg and Pull Request #20756.

Workarounds

• No workarounds are available for this vulnerability according to the security advisory
• Upgrading to the patched version is the only remediation option
• Network segmentation may provide temporary defense-in-depth until upgrade is complete

# Upgrade MinIO to the patched release
# Stop MinIO service
systemctl stop minio

# Download the patched release
wget https://dl.min.io/server/minio/release/linux-amd64/archive/minio.RELEASE.2024-12-13T22-19-12Z

# Replace the binary and restart
chmod +x minio.RELEASE.2024-12-13T22-19-12Z
mv minio.RELEASE.2024-12-13T22-19-12Z /usr/local/bin/minio

# Restart MinIO service
systemctl start minio

# Verify the version
minio --version