Executive Summary

This vulnerability exists in the Apache Airflow Samba provider's GCSToSambaOperator. The operator joins Google Cloud Storage (GCS) object names to the SMB destination path without properly checking if the resulting path stays within the intended destination directory.

Because the operator does not validate the path, an attacker who can write objects into the source GCS bucket can craft object names containing "../" segments. These segments allow the resolved write path to escape the configured destination directory, enabling the attacker to write files to arbitrary locations on the Samba target.

The issue was fixed by normalizing the resolved path and raising an exception if the path falls outside the allowed destination_path, ensuring that files are only written within the intended directory.

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Impact Analysis

This vulnerability can allow an attacker who has permission to write objects into the source GCS bucket to write files to arbitrary locations on the Samba target system.

Such unauthorized writes could lead to overwriting or creating files outside the intended directory, potentially compromising system integrity, causing data corruption, or enabling further attacks by placing malicious files in sensitive locations.

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Detection Guidance

Detection of this vulnerability involves checking for path traversal attempts in the usage of the GCSToSambaOperator, specifically looking for GCS object names containing ".." segments that could cause writes outside the intended destination path.

One approach is to audit logs or monitor file writes on the Samba target to identify any files being written outside the configured destination_path.

Since the vulnerability is related to the operator joining GCS object names to SMB paths without containment checks, you can look for suspicious object names in the source GCS bucket that include "../" sequences.

Specific commands are not provided in the resources, but you might consider commands such as:

• Using gsutil to list objects in the GCS bucket and filter for suspicious names: `gsutil ls gs://your-bucket/** | grep '\.\./'`
• Checking Samba target directories for unexpected files outside the intended destination path, for example: `find /path/to/samba/destination -type f` and verifying if any files exist outside the expected directory.
• Reviewing Airflow logs for errors or exceptions related to path traversal attempts if the fixed version is in place.

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Mitigation Strategies

The primary mitigation step is to upgrade the apache-airflow-providers-samba package to version 4.12.6 or later.

Version 4.12.6 includes a fix that validates the resolved destination path stays within the configured destination_path, preventing path traversal attacks.

Until the upgrade is applied, restrict write access to the source GCS bucket to trusted users only, preventing untrusted external data producers from writing objects with malicious names.

Additionally, monitor and audit the GCS bucket and Samba target directories for suspicious activity as a temporary measure.

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Compliance Impact

The vulnerability allows an attacker with write access to the source GCS bucket to write files to arbitrary locations on the Samba target outside the intended destination path. This unauthorized file write capability could lead to data integrity and confidentiality issues.

Such unauthorized access and potential data manipulation may impact compliance with standards and regulations like GDPR and HIPAA, which require strict controls over data access, integrity, and protection against unauthorized modification or disclosure.

However, the provided information does not explicitly discuss compliance impacts or specific regulatory considerations.

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