October 1, 2019
Ruby is prone to the following security vulnerabilities: 1. An authorization-bypass vulnerability 2. A denial-of-service vulnerability 3. An HTTP response-splitting vulnerability 4. A command-injection vulnerability An attacker can exploit these issues to bypass certain security restrictions and perform unauthorized actions, execute arbitrary commands, influence or misrepresent how web content is served, cached, and interpreted or cause excessive CPU resource consumption, resulting in denial-of-service conditions. The following products are affected: Ruby 2.3 and prior versions Ruby 2.4 versions prior to 2.4.7 Ruby 2.5 versions prior to 2.5.6 Ruby 2.6 versions prior to 2.6.4 Ruby 2.7.0-preview1
- Ruby-Lang Ruby 1.8
- Ruby-Lang Ruby 1.8.5
- Ruby-Lang Ruby 1.8.7
- Ruby-Lang Ruby 1.9
- Ruby-Lang Ruby 1.9.0
- Ruby-Lang Ruby 1.9.1
- Ruby-Lang Ruby 1.9.2
- Ruby-Lang Ruby 1.9.3
- Ruby-Lang Ruby 2.1.2
- Ruby-Lang Ruby 2.1.3
- Ruby-Lang Ruby 2.1.4
- Ruby-Lang Ruby 2.1.5
- Ruby-Lang Ruby 2.1.6
- Ruby-Lang Ruby 2.2.0
- Ruby-Lang Ruby 2.3.0
- Ruby-Lang Ruby 2.3.1
- Ruby-Lang Ruby 2.3.4
- Ruby-Lang Ruby 2.3.5
- Ruby-Lang Ruby 2.3.6
- Ruby-Lang Ruby 2.3.7
- Ruby-Lang Ruby 2.3.8
- Ruby-Lang Ruby 2.4.0
- Ruby-Lang Ruby 2.4.1
- Ruby-Lang Ruby 2.4.2
- Ruby-Lang Ruby 2.4.3
- Ruby-Lang Ruby 2.4.4
- Ruby-Lang Ruby 2.4.5
- Ruby-Lang Ruby 2.4.6
- Ruby-Lang Ruby 2.5.0
- Ruby-Lang Ruby 2.5.1
- Ruby-Lang Ruby 2.5.2
- Ruby-Lang Ruby 2.5.5
- Ruby-Lang Ruby 2.6
- Ruby-Lang Ruby 2.6.3
- Ruby-Lang Ruby 2.7.0-preview1
- Ubuntu Ubuntu Linux 16.04 LTS
- Ubuntu Ubuntu Linux 18.04 LTS
- Ubuntu Ubuntu Linux 19.04
- Ubuntu Ubuntu Linux 19.10
Block external access at the network boundary, unless external parties require service.
Filter access to the affected computer at the network boundary if global access isn't needed. Restricting access to only trusted computers and networks might greatly reduce the likelihood of a successful exploit.
Run all software as a nonprivileged user with minimal access rights.
When possible, run all software as a user with minimal privileges and limited access to system resources. Use additional precautions such as restrictive environments to insulate software that may potentially handle malicious content.
Deploy network intrusion detection systems to monitor network traffic for malicious activity.
Deploy NIDS to monitor network traffic for signs of anomalous or suspicious activity including unexplained incoming and outgoing traffic. This may indicate exploit attempts or activity that results from successful exploits.
Do not follow links provided by unknown or untrusted sources.
Web users should be cautious about following links to sites that are provided by unfamiliar or suspicious sources. Filtering HTML from emails may help remove a possible vector for transmitting malicious links to users.
Updates are available. Please see the references or vendor advisory for more information.
- hackerone - [CVE-2019-15845] - POC - Null character at fnmatch
- hackerone - [CVE-2019-16254] - POC - HTTP header can split /[\r\n]/ instead of /\r\n/
- hackerone - [CVE-2019-16255] - POC - Potential command injection in `Shell#` and `Shell#te
- RedHat - Bug 1773728 (CVE-2019-16201) - CVE-2019-16201 ruby: regular expression denial of
- Ruby - Ruby 2.4.8 released
- Ruby - Ruby 2.5.7 released
- Ruby - Ruby 2.6.5 released
- Yukihiro Matsumoto - Ruby Home Page
ooooooo_q (ooooooo_q), ceh (358) and Kazuhiro NISHIYAMA (znz).
© 1995- Symantec Corporation
Permission to redistribute this alert electronically is granted as long as it is not edited in any way unless authorized by Symantec Security Response. Reprinting the whole or part of this alert in any medium other than electronically requires permission from firstname.lastname@example.org.
The information in the advisory is believed to be accurate at the time of publishing based on currently available information. Use of the information constitutes acceptance for use in an AS IS condition. There are no warranties with regard to this information. Neither the author nor the publisher accepts any liability for any direct, indirect, or consequential loss or damage arising from use of, or reliance on, this information.
Symantec, Symantec products, Symantec Security Response, and email@example.com are registered trademarks of Symantec Corp. and/or affiliated companies in the United States and other countries. All other registered and unregistered trademarks represented in this document are the sole property of their respective companies/owners.