Categories: Security

What is the ‘Yahoobleed’ Bug and How It Affects You

Because many malicious online attacks occur using content that mimics familiar companies and their content, it’s best to run a full virus scan after downloading any files from the Internet or from your email. Click below to run check your phone for malware:

A complete scan effectively checks every inch of your device for any malware or security breaches to avoid a loss of personal information.

What is Yahoobleed?
Chris Evans, a security expert, discovered two crucial vulnerabilities in Yahoo’s image processing library earlier this year that put Yahoo users at serious risk of a security breach. The vulnerabilities discovered by Evans have been aptly named “Yahoobleed,” in reference to the resulting leak of information that can be exploited by a malicious attacker. Caused by Yahoo’s negligence and an error in the code, the two issues were directly related to ImageMagick, which is used by Yahoo to condense, convert, and store large image files sent via email.

Shockingly, one of these serious bugs could have easily been avoided had Yahoo updated their version of ImageMagick in 2015 when the company released a new patch to prevent the error. Evans tested his theories on Yahoo’s security by sending himself a malicious email attachment. After opening the file, he discovered that if an attacker employed a similar technique, he could receive access to other private email attachments as well as sensitive information stored in the server memory. If a Yahoo email user opened one of these malicious attachments, it would result in the namesake leak of information to the end user, the attacker.

After Evans discovered the second vulnerability, Yahoo made the decision to halt the use of ImageMagick in an attempt to prevent any further breaches of security. Although many commend Yahoo for their decision, these vulnerabilities are not uncommon and still pose a serious threat. At this time, the company believes the issue has been resolved.

How to Protect Yourself Online
While Yahoo may no longer have an issue with “Yahoobleed,” the recent vulnerabilities should be a reminder that even trusted institutions like Yahoo are subject to attack. Basic best practices in preventing a leak of personal information should include selective engagement with spam emails and regular virus scanning. First and foremost, do not open an email or an email attachment from a sender that you do not recognize or that looks potentially malicious. If the email appears to be from a familiar sender but is asking for new information or using a heightened sense of urgency that is inconsistent with their typical email content, do not click on any links or download attachments.

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The dfndr blog is an informative channel that presents exclusive content on security and privacy in the mobile and business world, with tips to keep users protected. Populated by a select group of expert reporters, the channel has a partnership with dfndr lab's security team. Together they bring you, first-notice news about attacks, scams, internet vulnerabilities, malware and everything affecting cybersecurity.