Vulnerability identifier: #VU11542

Vulnerability risk: Low

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-2018-8780

CWE-ID: CWE-22

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Ruby
Universal components / Libraries / Scripting languages

Vendor: Ruby

Description
The vulnerability allows a remote attacker to obtain potentially sensitive information and write arbitrary files on the target system.

The weakness exists in the Dir.open, Dir.new, Dir.entries and Dir.empty? methods due to improper checking of NULL characters. A remote attacker can trigger the unintentional directory traversal.

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/poisoned-nul-byte-dir-cve-2018-8780/

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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.