Denial of service in Prototype

1) Incorrect Regular Expression

EUVDB-ID: #VU71773

Risk: Low

CVSSv3.1: 4.6 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-27511

CWE-ID: CWE-185 - Incorrect Regular Expression

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to insufficient input validation in the stripTags and unescapeHTML components. A remote attacker can pass specially crafted data to the application and perform regular expression denial of service (ReDos) attack.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Prototype JavaScript Framework: 1.5.0 - 1.7.3

CPE2.3

• cpe:2.3:a:prototype_core_team:prototype_javascript_framework:1.7.3:*:*:*:*:*:*:*
• cpe:2.3:a:prototype_core_team:prototype_javascript_framework:1.7.2:*:*:*:*:*:*:*
• cpe:2.3:a:prototype_core_team:prototype_javascript_framework:1.7.1:*:*:*:*:*:*:*

External links

http://prototypejs.org/
http://github.com/yetingli/PoCs/blob/main/CVE-2020-27511/Prototype.md
http://github.com/prototypejs/prototype/blob/dee2f7d8611248abce81287e1be4156011953c90/src/prototype/lang/string.js#L283

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.