Opera says hackers pilfered expired code-signing certificate

A few thousand Windows users may have been automatically infected during a 36-minute period

Opera Software said Wednesday hackers pilfered from its internal systems at least one code-signing certificate that was used to sign malicious software.

The Oslo-based company, which makes a mobile and desktop web browser, wrote in a blog post that it believes a few thousand Windows users may have automatically installed malicious software between 01.00 and 01.36 UTC on June 19, the day the attack was detected and halted.

Code-signing certificates are used to cryptographically verify that a piece of software comes from its purported publisher. By using the certificate, it would have appeared to users that the malware was legitimate software from Opera, such as the company's browser.

In its post, Opera included a link to VirusTotal, a website that tests malware samples against security programs to see if the malware is detected. The VirusTotal page shows the SHA256 hash of what is presumably the malware that used the expired code-signing certificate.

At the time of writing, just over half of the 47 security programs listed on VirusTotal that tested the sample detected it. The figure will likely rise as vendors tweak their programs to detect it.

Sigbjørn Vik, an Opera developer and quality assurance engineer, wrote that the certificate was expired, but did not reveal further details. The company said it has since cleaned its systems and that it does not believe user data was lost.

"We are working with the relevant authorities to investigate its source and any potential further extent," Vik wrote.

Opera is planning to release a new version of its browser with a new code-signing certificate, but did not say when it will be available.

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

Join the newsletter!

Or

Sign up to gain exclusive access to email subscriptions, event invitations, competitions, giveaways, and much more.

Membership is free, and your security and privacy remain protected. View our privacy policy before signing up.

Error: Please check your email address.

Tags opera software

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

Brand Post

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Luke Hill

MSI GT75 TITAN

I need power and lots of it. As a Front End Web developer anything less just won’t cut it which is why the MSI GT75 is an outstanding laptop for me. It’s a sleek and futuristic looking, high quality, beast that has a touch of sci-fi flare about it.

Emily Tyson

MSI GE63 Raider

If you’re looking to invest in your next work horse laptop for work or home use, you can’t go wrong with the MSI GE63.

Laura Johnston

MSI GS65 Stealth Thin

If you can afford the price tag, it is well worth the money. It out performs any other laptop I have tried for gaming, and the transportable design and incredible display also make it ideal for work.

Andrew Teoh

Brother MFC-L9570CDW Multifunction Printer

Touch screen visibility and operation was great and easy to navigate. Each menu and sub-menu was in an understandable order and category

Louise Coady

Brother MFC-L9570CDW Multifunction Printer

The printer was convenient, produced clear and vibrant images and was very easy to use

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.

Featured Content

Product Launch Showcase

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?