RubyGems DNS flaw now patched after second try

Those using the distribution client are advised to patch immediately to version 2.4.8 or higher

RubyGem has released a second fix for a flaw that could be used to substitute a legitimate Ruby program with malware during downloading.

RubyGem has released a second fix for a flaw that could be used to substitute a legitimate Ruby program with malware during downloading.

A revised patch has been released for a flaw in the distribution platform for Ruby applications, RubyGems, which could be used to deliver malware to someone trying to download a program.

RubyGems lets people search for a "gem," which is a packaging format for Ruby applications and code libraries. Ruby developers publish a gem when an application is ready.

Security researchers from Trustwave found a problem with the platform. When people search for a gem, RubyGems uses a DNS (Domain Name System) SRV record request to find a server hosting a particular gem.

The request, however, "does not require that DNS replies come from the same security domain as the original gem source," according to a writeup, which Trustwave plans to release on its blog on Tuesday.

An attacker using the flaw could redirect a RubyGems client to download a gem from a different server and instead supply a malicious program, Trustwave wrote. It then bypasses any SSL/TLS check.

"We wrote a fully functional gem trojaning service that demonstrates how an attacker could simply trojan Ruby gems transparently over the wire while the user was installing them," Trustwave wrote.

Most gems aren't digitally signed, either, so there's no second check to ensure a program is what it purports to be. Some 1.2 million gems are installed a day, so there's a large potential group of victims, according to Trustwave, which also collaborated with OpenDNS to get insight on the number of DNS SRV requests for gems.

RubyGems issued a patch for the flaw in mid-May, but it was incomplete, wrote Jonathan Claudius, lead security researcher at Trustwave, in an email. The organization released a second patch on June 8. The fix validates the SRV record under the original domain, according to a RubyGems blog post.

Trustwave decided to hold off publishing information on the flaw until now to give people time to patch, Claudius said. "Users are slow to fix it," he wrote.

The flaw is CVE-2015-3900, and users should be running version 2.4.8 or greater of RubyGems. Versions between 2.0 and 2.4.6 are vulnerable.

Send news tips and comments to jeremy_kirk@idg.com. Follow me on Twitter: @jeremy_kirk

Join the newsletter!

Error: Please check your email address.
Rocket to Success - Your 10 Tips for Smarter ERP System Selection

Tags securitytrustwaveExploits / vulnerabilities

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Jeremy Kirk

IDG News Service
Show Comments

Cool Tech

Breitling Superocean Heritage Chronographe 44

Learn more >

SanDisk MicroSDXC™ for Nintendo® Switch™

Learn more >

Toys for Boys

Family Friendly

Panasonic 4K UHD Blu-Ray Player and Full HD Recorder with Netflix - UBT1GL-K

Learn more >

Stocking Stuffer

Razer DeathAdder Expert Ergonomic Gaming Mouse

Learn more >

Christmas Gift Guide

Click for more ›

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Edwina Hargreaves

WD My Cloud Home

I would recommend this device for families and small businesses who want one safe place to store all their important digital content and a way to easily share it with friends, family, business partners, or customers.

Walid Mikhael

Brother QL-820NWB Professional Label Printer

It’s easy to set up, it’s compact and quiet when printing and to top if off, the print quality is excellent. This is hands down the best printer I’ve used for printing labels.

Ben Ramsden

Sharp PN-40TC1 Huddle Board

Brainstorming, innovation, problem solving, and negotiation have all become much more productive and valuable if people can easily collaborate in real time with minimal friction.

Sarah Ieroianni

Brother QL-820NWB Professional Label Printer

The print quality also does not disappoint, it’s clear, bold, doesn’t smudge and the text is perfectly sized.

Ratchada Dunn

Sharp PN-40TC1 Huddle Board

The Huddle Board’s built in program; Sharp Touch Viewing software allows us to easily manipulate and edit our documents (jpegs and PDFs) all at the same time on the dashboard.

George Khoury

Sharp PN-40TC1 Huddle Board

The biggest perks for me would be that it comes with easy to use and comprehensive programs that make the collaboration process a whole lot more intuitive and organic

Featured Content

Product Launch Showcase

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?