Vulnerability identifier: #VU11537

Vulnerability risk: Low

CVSSv3.1: 3.8 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2017-17742

CWE-ID: CWE-113

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Ruby
Universal components / Libraries / Scripting languages

Vendor: Ruby

Description
The vulnerability allows a remote attacker to perform HTTP response splitting attack.

The weakness exists due to improper handling of HTTP requests. If a script accepts an external input and outputs it without modification as a part of HTTP responses, a remote attacker can use newline characters to trick the victim that the HTTP response header is stopped at there and inject fake HTTP responses after the newline characters to show malicious contents to the victim.

Mitigation
Update to versions 2.2.10, 2.3.7, 2.4.4 or 2.5.1.

Vulnerable software versions

Ruby: 2.2.0 - 2.6.0-preview1

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External links
http://www.ruby-lang.org/en/news/2018/03/28/http-response-splitting-in-webrick-cve-2017-17742/

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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.