#VU71542 Incorrect Regular Expression in Websocket-extensions - CVE-2020-7663

Vulnerability identifier: #VU71542

Vulnerability risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2020-7663

CWE-ID: CWE-185

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Websocket-extensions

Vendor: Abdul Rafay

Description

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

The vulnerability exists due to insufficient input validation when processing  a malicious payload with the Sec-WebSocket-Extensions header. 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

Websocket-extensions: 0.1.0 - 0.1.4

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External links
https://blog.jcoglan.com/2020/06/02/redos-vulnerability-in-websocket-extensions
https://github.com/faye/websocket-extensions-ruby/security/advisories/GHSA-g6wq-qcwm-j5g2
https://github.com/faye/websocket-extensions-ruby/commit/aa156a439da681361ed6f53f1a8131892418838b
https://snyk.io/vuln/SNYK-RUBY-WEBSOCKETEXTENSIONS-570830
https://lists.debian.org/debian-lts-announce/2020/08/msg00031.html
https://usn.ubuntu.com/4502-1/

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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.