Arch Linux Security Advisory ASA-201910-2 ========================================= Severity: Medium Date : 2019-10-02 CVE-ID : CVE-2019-15845 CVE-2019-16201 CVE-2019-16254 CVE-2019-16255 Package : ruby Type : multiple issues Remote : Yes Link : https://security.archlinux.org/AVG-1039 Summary ======= The package ruby before version 2.6.5-1 is vulnerable to multiple issues including arbitrary code execution, content spoofing, denial of service and insufficient validation. Resolution ========== Upgrade to 2.6.5-1. # pacman -Syu "ruby>=2.6.5-1" The problems have been fixed upstream in version 2.6.5. Workaround ========== None. Description =========== - CVE-2019-15845 (insufficient validation) It has been discovered that Ruby before 2.4.8, 2.5.7 and 2.6.5 is vulnerable to NUL injection in built-in methods (File.fnmatch and File.fnmatch?). An attacker who has the control of the path pattern parameter could exploit this vulnerability to make path matching pass despite the intention of the program author. The Built-in methods File.fnmatch and its alias File.fnmatch? accept the path pattern as their first parameter. When the pattern contains NUL character (\0), the methods recognize that the path pattern ends immediately before the NUL byte. Therefore, a script that uses an external input as the pattern argument, an attacker can make it wrongly match a pathname that is the second parameter. - CVE-2019-16201 (denial of service) It has been discovered that Ruby before 2.4.8, 2.5.7 and 2.6.5 is vulnerable to denial of service via regular expressions in WEBrick's Digest access authentication module. An attacker can exploit this vulnerability to cause an effective denial of service against a WEBrick service. - CVE-2019-16254 (content spoofing) It has been discovered that Ruby before 2.4.8, 2.5.7 and 2.6.5 is vulnerable to HTTP response splitting in WEBrick bundled with Ruby. If a program using WEBrick inserts untrusted input into the response header, an attacker can exploit it to insert a newline character to split a header, and inject malicious content to deceive clients. This is the same issue as CVE-2017-17742. The previous fix was incomplete, which addressed the CRLF vector, but did not address an isolated CR or an isolated LF. - CVE-2019-16255 (arbitrary code execution) It has been discovered that Ruby before 2.4.8, 2.5.7 and 2.6.5 is vulnerable to code injection. Shell#[] and its alias Shell#test defined in lib/shell.rb allow code injection if the first argument (aka the “command” argument) is untrusted data. An attacker can exploit this to call an arbitrary Ruby method. Impact ====== A remote attacker is able to bypass path restrictions, perform a denial of service attack, inject malicious content or call an arbitrary Ruby method under certain circumstances. References ========== https://bugs.archlinux.org/task/63977 https://www.ruby-lang.org/en/news/2019/10/01/ruby-2-6-5-released/ https://www.ruby-lang.org/en/news/2019/10/01/nul-injection-file-fnmatch-cve-... https://www.ruby-lang.org/en/news/2019/10/01/webrick-regexp-digestauth-dos-c... https://www.ruby-lang.org/en/news/2019/10/01/http-response-splitting-in-webr... https://www.ruby-lang.org/en/news/2019/10/01/code-injection-shell-test-cve-2... https://security.archlinux.org/CVE-2019-15845 https://security.archlinux.org/CVE-2019-16201 https://security.archlinux.org/CVE-2019-16254 https://security.archlinux.org/CVE-2019-16255