Horizon Alert
Summary of the vulnerability and why it matters
This issue in PhpSpreadsheet allows an attacker to execute code on your server or trick it into making requests to external systems. This is possible when the library processes spreadsheet files uploaded or referenced by users, potentially leading to significant compromise of your application's integrity and data.
- Attacker can run arbitrary code.
- Application can be tricked into making unintended requests.
- Affects applications processing user-provided files.
Attack Path
How an attacker could exploit the issue
An attacker can exploit this by tricking a user into uploading a specially crafted file to an application using a vulnerable version of PhpSpreadsheet. This crafted file can cause the application to execute arbitrary PHP code or perform unauthorized network requests on the server.
- User-controlled filenames can be weaponized.
- PHAR deserialization leads to RCE.
- Remote file wrappers cause SSRF.
Live Threat
Current exploitation, exposure, and threat context
This vulnerability in PhpSpreadsheet allows for remote code execution or server-side request forgery when handling user-controlled filenames that leverage PHP stream wrappers. Attackers would likely favor this vulnerability for its potential to achieve arbitrary code execution with minimal authentication requirements, making it attractive for widespread exploitation. The ability to inject stream wrappers like phar:// to trigger deserialization is a well-understood attack vector.
- Exploitation is possible via user input.
- Vulnerable to RCE and SSRF.
- Fixes released for multiple versions.
Priority actions
Operational Fix
Recommended remediation, mitigation, and detection steps
Prioritize patching or updating PhpSpreadsheet to a secure version immediately, as vulnerable versions allow remote code execution or server-side request forgery through crafted spreadsheet files. If patching is delayed, implement input validation and content security policy to mitigate risks associated with user-supplied file paths and stream wrappers.
- Update to 1.30.3, 2.1.15, 2.4.4, 3.10.4, or 5.6.0.
- Validate all user-supplied filenames.
- Monitor for unexpected network traffic.
