XenForo <= 2.2.13 (ArchiveImport.php) Zip Slip Vulnerability

https://xenforo.com

• Affected Versions:

Version 2.2.13 and prior versions.

• Vulnerability Description:

The vulnerability is located in the /src/XF/Service/Style/ArchiveImport.php script.

Specifically, into the ArchiveImport::extractFilesToTempDir() method:

198	public function extractFilesToTempDir()
199	{
200		$zip = $this->zip();
201		$DS = \XF::$DS;
202
203		if ($this->extracted)
204		{
205			return;
206		}
207
208		for ($i = 0; $i < $zip->numFiles; $i++)
209		{
210			$zipFileName = $zip->getNameIndex($i);
211			$fsFileName = $this->getFsFileNameFromZipName($zipFileName);
212			if ($fsFileName === null)
213			{
214				continue;
215			}
216
217			$finalFileName = $this->tempDir . $DS . $fsFileName;
218
219			$dataStream = $zip->getStream($zipFileName);
220			@File::writeFile($finalFileName, $dataStream, false);
221		}

The vulnerability exists because the above code is using the filename provided within the Zip archive ($zipFileName variable created at line 210) to write the extracted file by using File::writeFile() at line 220, without properly verifying whether it contains Path Traversal sequences. This could be exploited to carry out Zip Slip (or Path Traversal) attacks and write/overwrite arbitrary files on the web server, resulting in execution of arbitrary PHP code or other security impacts. Successful exploitation of this vulnerability requires an account with permissions to administer styles.

• Solution:

Upgrade to version 2.2.14 or later.

• Disclosure Timeline:

[02-01-2024] - Vendor notified

[17-01-2024] - CVE identifier requested

[24-01-2024] - Vendor replied a fix will be available in the next release

[30-01-2024] - Version 2.2.14 released

[30-01-2024] - Publication of this advisory

• CVE Reference:

The Common Vulnerabilities and Exposures project (cve.mitre.org) has not assigned a CVE identifier for this vulnerability.

• Credits:

Vulnerability discovered by Egidio Romano.

• Other References:

https://xenforo.com/tickets/BC37EB98/?v=5da7bd5728