CVE-2024-1456 Overview
CVE-2024-1456 is an S3 bucket takeover vulnerability affecting the h2oai/h2o-3 repository. The issue involves the S3 bucket referenced at s3.amazonaws.com/h2o-training, which was found to be vulnerable to unauthorized takeover. An attacker who claims the abandoned bucket name can serve controlled content from a trusted-looking H2O.ai training endpoint. This condition is classified under [CWE-840] Business Logic Errors and impacts H2O version 3.45.0.6386.
Critical Impact
An attacker who successfully takes over the referenced S3 bucket can distribute malicious training assets or code to users who trust the original H2O.ai domain path, resulting in compromised confidentiality and integrity.
Affected Products
- H2O h2o version 3.45.0.6386
- Deployments of the h2oai/h2o-3 repository that reference s3.amazonaws.com/h2o-training
- Downstream tools consuming H2O training resources from the affected bucket path
Discovery Timeline
- 2024-04-16 - CVE-2024-1456 published to the National Vulnerability Database (NVD)
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2024-1456
Vulnerability Analysis
The h2oai/h2o-3 repository references an Amazon S3 bucket, h2o-training, hosted under s3.amazonaws.com. The bucket was not owned or actively controlled, allowing an external party to register the same bucket name and assume control of the resource path. Once claimed, the attacker controls every object served from that URL.
Because the repository and its documentation direct users and automated tooling to fetch training data or artifacts from this location, the attacker can substitute arbitrary content. This is a business logic flaw rather than a memory or protocol issue. The trust relationship is inherited from the original bucket name, not from any code weakness in H2O itself.
Exploitation requires user interaction, since victims must load or execute content retrieved from the hijacked bucket. Impact on confidentiality and integrity is high, while availability is unaffected because the original resource is simply replaced rather than denied.
Root Cause
The root cause is a dangling reference to an unclaimed or deleted S3 bucket. When the original bucket was decommissioned, the bucket name became globally re-registerable in AWS. The repository retained hardcoded references to the resource, creating a stale trust anchor.
Attack Vector
An attacker registers the abandoned bucket h2o-training in their own AWS account. They then upload malicious objects using the same paths referenced by h2oai/h2o-3 documentation, notebooks, or code. Users following training material or scripts fetch attacker-controlled content over an ostensibly legitimate URL. No authentication bypass is needed because bucket ownership itself grants full authority over the namespace.
Technical details of the takeover primitive are documented in the Huntr bug bounty listing.
Detection Methods for CVE-2024-1456
Indicators of Compromise
- Outbound HTTP or HTTPS requests to s3.amazonaws.com/h2o-training from developer workstations, CI runners, or data science environments
- Unexpected file hashes returned from the h2o-training bucket compared to previously cached artifacts
- Execution of scripts or notebooks that download resources from the affected bucket path
Detection Strategies
- Inventory all internal repositories, notebooks, container images, and CI pipelines that reference h2o-training in s3.amazonaws.com URLs.
- Query proxy, DNS, and network telemetry for historical connections to the affected bucket and correlate with H2O usage.
- Validate integrity of any downloaded H2O training datasets against known-good hashes published by H2O.ai.
Monitoring Recommendations
- Alert on new outbound requests to the deprecated bucket path from production and analyst systems.
- Monitor Python and R runtime activity that follows H2O artifact downloads for anomalous process execution.
- Track version drift of h2o Python and Java packages across the environment to identify systems running 3.45.0.6386 or earlier.
How to Mitigate CVE-2024-1456
Immediate Actions Required
- Remove or update all references to s3.amazonaws.com/h2o-training in internal code, documentation, notebooks, and Dockerfiles.
- Block outbound access to the specific bucket path at the proxy or firewall until upstream references are remediated.
- Rebuild any container images or virtual environments that may have cached malicious content fetched from the hijacked bucket.
Patch Information
No vendor patch is listed in the NVD entry at the time of publication. Users should monitor the Huntr bug bounty listing and the official H2O.ai project channels for remediation guidance and updated artifact hosting locations.
Workarounds
- Mirror required H2O training assets internally and pin all references to the internally hosted, integrity-verified copies.
- Enforce checksum verification on any file retrieved from third-party S3 buckets used in machine learning pipelines.
- Restrict developer and CI environments to an allowlist of trusted artifact repositories, excluding the deprecated bucket path.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
