Vulnerability identifier: #VU47252

Vulnerability risk: Medium

CVSSv3.1: 5.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-7070

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
PHP
Universal components / Libraries / Scripting languages

Vendor: PHP Group

Description

The vulnerability allows a remote attacker to perform a spoofing attack.

The vulnerability exists in the way PHP parser handles cookies with percent character (e.g. '%'). A remote attacker can send a crafted HTTP request with a `__%48ost-` or `__%53ecure-` cookie that will be processed before other cookies sent in the same request. As a result, an attacker can set malicious `__Host-` cookie on a subdomain and bypass origin restrictions, imposed by browsers.

Successful exploitation of the vulnerability may allow an attacker to perform a spoofing attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

PHP: 7.4 - 7.4.10, 7.3 - 7.3.22, 7.2 - 7.2.33

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External links
http://www.php.net/ChangeLog-7.php#7.4.11
http://bugs.php.net/bug.php?id=79699

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.