GHSA-w9xv-qf98-ccq4

Опубликовано: 07 окт. 2024

Источник: github

Github: Прошло ревью

CVSS4: 6

CVSS3: 6.3

Описание

PhpSpreadsheet allows absolute path traversal and Server-Side Request Forgery in HTML writer when embedding images is enabled

Summary

It's possible for an attacker to construct an XLSX file that links images from arbitrary paths. When embedding images has been enabled in HTML writer with $writer->setEmbedImages(true); those files will be included in the output as data: URLs, regardless of the file's type. Also URLs can be used for embedding, resulting in a Server-Side Request Forgery vulnerability.

Details

XLSX files allow embedding or linking media. When

In xl/drawings/drawing1.xml an attacker can do e.g.:

<a:blip cstate="print" r:link="rId1" />

And then, in xl/drawings/_rels/drawing1.xml.rels they can set the path to anything, such as:

When the HTML writer is outputting the image, it does not check the path in any way. Also the getimagesize() call does not mitigate this, because when getimagesize() returns false, an empty mime type is used.

if ($this->embedImages || str_starts_with($imageData, 'zip://')) { $picture = @file_get_contents($filename); if ($picture !== false) { $imageDetails = getimagesize($filename) ?: ['mime' => '']; // base64 encode the binary data $base64 = base64_encode($picture); $imageData = 'data:' . $imageDetails['mime'] . ';base64,' . $base64; } } $html .= '<img style="position: absolute; z-index: 1; left: ' . $drawing->getOffsetX() . 'px; top: ' . $drawing->getOffsetY() . 'px; width: ' . $drawing->getWidth() . 'px; height: ' . $drawing->getHeight() . 'px;" src="' . $imageData . '" alt="' . $filedesc . '" />';

PoC

<?php require 'vendor/autoload.php'; $reader = \PhpOffice\PhpSpreadsheet\IOFactory::createReader("Xlsx"); $spreadsheet = $reader->load(__DIR__ . '/book.xlsx'); $writer = new \PhpOffice\PhpSpreadsheet\Writer\Html($spreadsheet); $writer->setEmbedImages(true); $output = $writer->generateHTMLAll(); // The below is just for demo purposes $pattern = '/data:;base64,(?<data>[^"]+)/i'; preg_match_all($pattern, $output, $matches); print("*** /etc/passwd content: ***\n"); print(base64_decode($matches['data'][0])); print("*** HTTP response content: ***\n"); print(base64_decode($matches['data'][1]));

Add this file in the same directory: book.xlsx

Run with: php index.php

Impact

When embedding images has been enabled, an attacker can read arbitrary files on the server and perform arbitrary HTTP GET requests, potentially e.g. revealing secrets. Note that any PHP protocol wrappers can be used, meaning that if for example the expect:// wrapper is enabled, also remote code execution is possible.

Ссылки

Пакеты

Наименование

phpoffice/phpspreadsheet

composer

Затронутые версииВерсия исправления

>= 2.2.0, < 2.3.0

2.3.0

Наименование

phpoffice/phpspreadsheet

composer

Затронутые версииВерсия исправления

< 1.29.2

1.29.2

Наименование

phpoffice/phpspreadsheet

composer

Затронутые версииВерсия исправления

>= 2.0.0, < 2.1.1

2.1.1

Наименование

phpoffice/phpexcel

composer

Затронутые версииВерсия исправления

<= 1.8.2

Отсутствует

EPSS

Процентиль: 71%

0.00656

Низкий

6 Medium

CVSS4

6.3 Medium

CVSS3

CVE ID

CVE-2024-45291

Дефекты

CWE-22

CWE-36

CWE-918

Связанные уязвимости

CVE-2024-45291

CVSS3: 6.3

nvd

больше 1 года назад

PHPSpreadsheet is a pure PHP library for reading and writing spreadsheet files. It's possible for an attacker to construct an XLSX file that links images from arbitrary paths. When embedding images has been enabled in HTML writer with `$writer->setEmbedImages(true);` those files will be included in the output as `data:` URLs, regardless of the file's type. Also URLs can be used for embedding, resulting in a Server-Side Request Forgery vulnerability. When embedding images has been enabled, an attacker can read arbitrary files on the server and perform arbitrary HTTP GET requests. Note that any PHP protocol wrappers can be used, meaning that if for example the `expect://` wrapper is enabled, also remote code execution is possible. This issue has been addressed in release versions 1.29.2, 2.1.1, and 2.3.0. All users are advised to upgrade. there are no known workarounds for this vulnerability.

EPSS

Процентиль: 71%

0.00656

Низкий

6 Medium

CVSS4

6.3 Medium

CVSS3

CVE ID

CVE-2024-45291

Дефекты

CWE-22

CWE-36

CWE-918