CVE-2022-39217 is a vulnerability classified under CWE-74, which pertains to improper neutralization of special elements in output used by a downstream component, commonly known as an injection flaw. The affected product is some-natalie's ghas-to-csv, a GitHub Action designed to extract data from the GitHub Advanced Security (GHAS) API and export it into a CSV file format. The vulnerability exists in versions prior to v1, where the GitHub Action fails to sanitize or neutralize potentially malicious content retrieved from the GHAS API before writing it into the CSV file. Specifically, if any alert dismissal notes or custom fields within the GHAS data contain executable code or spreadsheet formulas, these can be embedded directly into the CSV output. When an endpoint user opens this CSV file in a spreadsheet application such as Microsoft Excel or LibreOffice Calc, the embedded formulas or code may execute automatically or upon user interaction, leading to potential code execution or data manipulation on the client side. This type of attack vector is often referred to as CSV injection or formula injection. The vulnerability does not require authentication beyond what is needed to access the GHAS API, but it does require that the user open the crafted CSV file in a vulnerable spreadsheet program. The issue has been addressed in version v1 of the ghas-to-csv GitHub Action by implementing proper sanitization of the output data to neutralize any special characters or formulas before writing to the CSV. No known exploits are currently reported in the wild, and no workarounds exist other than upgrading to the fixed version. This vulnerability primarily impacts organizations that utilize the ghas-to-csv GitHub Action in their CI/CD pipelines or security reporting workflows and subsequently share or open the generated CSV files without additional sanitization controls.

For European organizations, the impact of this vulnerability is primarily on the confidentiality and integrity of endpoint systems where the CSV files are opened. If malicious formulas or code are embedded in the CSV, attackers could execute arbitrary commands or scripts on the user's machine, potentially leading to data theft, lateral movement within the network, or further compromise of sensitive systems. This risk is heightened in organizations that heavily rely on GitHub Advanced Security data for compliance, vulnerability management, or security reporting and use the ghas-to-csv action to automate report generation. Since the vulnerability requires user interaction to open the CSV file, the attack surface is somewhat limited but still significant in environments where CSV files are shared across teams or with third parties. The availability impact is low as the vulnerability does not directly cause denial of service. However, successful exploitation could lead to operational disruptions if endpoint systems are compromised. Given the widespread use of spreadsheet software in European enterprises and the increasing adoption of GitHub Actions for DevOps automation, this vulnerability poses a moderate risk, especially in sectors with high security requirements such as finance, healthcare, and critical infrastructure. The lack of known exploits reduces immediate urgency but does not eliminate the risk of future targeted attacks.

European organizations should immediately upgrade any usage of the ghas-to-csv GitHub Action to version v1 or later, where the vulnerability has been fixed. Beyond upgrading, organizations should implement strict validation and sanitization of any CSV files generated from external or automated sources before opening them in spreadsheet applications. This can include: 1) Using CSV viewers or parsers that do not automatically execute formulas; 2) Configuring spreadsheet software to disable automatic formula execution or enable 'safe mode' when opening files from untrusted sources; 3) Educating users about the risks of opening CSV files from automated tools without verification; 4) Implementing endpoint protection solutions that can detect and block suspicious macro or formula execution; 5) Incorporating security scanning of CI/CD workflows to detect usage of vulnerable GitHub Actions and enforce automatic updates. Additionally, organizations should review their internal processes for sharing CSV reports and consider alternative formats (e.g., JSON or PDF) that do not support executable content for sensitive security data exports. Finally, monitoring for anomalous behavior on endpoints that open such CSV files can help detect potential exploitation attempts early.