CVE-2024-56366: PhpSpreadsheet allows unauthorized Reflected XSS in the Accounting.php file

Unauthorized Reflected XSS in the <code>Accounting.php</code> 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/Wizards/NumberFormat/Accounting.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/Wizards/NumberFormat/Accounting.php file Exploitation conditions: an unauthorized user Mitigation: sanitization of the currency variable Researcher: Aleksey Solovev (Positive Technologies)

Research

The researcher discovered zero-day vulnerability Unauthorized Reflected Cross-Site Scripting (XSS) (in Accounting.php file) in Phpspreadsheet.

There is no sanitization in the /vendor/phpoffice/phpspreadsheet/samples/Wizards/NumberFormat/Accounting.php file, which leads to the possibility of a XSS attack. Strings are formed using the currency parameter without sanitization, which is controlled by the attacker.

Figure 7. A fragment of the query in which a string and a parameter are formed without sanitization

An attacker can prepare a special HTML form that will be automatically sent to the vulnerable scenario.

Listing 4. HTML form that demonstrates the exploitation of the XSS vulnerability