#VU11541 Poison null byte in Ruby - CVE-2018-8779

Vulnerability identifier: #VU11541

Vulnerability risk: Low

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2018-8779

CWE-ID: CWE-626

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Ruby
Universal components / Libraries / Scripting languages

Vendor: Ruby

Description
The vulnerability allows a remote attacker to write arbitrary files on the target system.

The weakness exists in the UNIXServer.open and UNIXSocket.open methods due to improper checking of null characters. A remote attacker can accept the socket file in the unintentional path.

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

---

External links
https://www.ruby-lang.org/en/news/2018/03/28/poisoned-nul-byte-unixsocket-cve-2018-8779/

---

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.