Apple and WordPress fix dangerous threats to browsers

Apple has released new versions of Safari for its three latest versions of OS X, addressing flaws that could allow a remote attacker to take control of a hacked system via malicious websites.

Apple flagged the updates on Wednesday in a support page, detailing five flaws most of which can be exploited if a vulnerable browser visits a maliciously crafted website and all stemming from WebKit.

The bugs are fixed in the new versions of Safari for OS X Mountain Lion, OS X Mavericks, and OS X Yosemite. These are Safari 8.0.6, 7.1.6, and 6.2.6, updating the respective versions that Apple released a month ago alongside security updates for the three versions of OS X.

Mac users running Safari 8.0.5, Safari 7.1.5, and Safari 6.2.5 are vulnerable to three memory corruption bugs in WebKit that could be trigged by visiting a maliciously crafted website, and could cause either the application to crash or “execute arbitrary code”.

Unlike many other large software vendors Apple doesn’t rate the severity of its security updates, but US-CERT notes that the flaws “may allow a remote attacker to take control of the affected system”, which is about as serious as it gets.

Apple employees discovered the three memory bugs.

Also, unlike a growing number of software vendors, Apple doesn’t pay out bug bounties for researchers that report flaws to the company, but it does give credit.

Apple noted Joe Vennix, a Metasploit engineer at security firm Rapid7, discovered another potentially serious issue in WebKit.

“A state management issue existed in Safari that allowed unprivileged origins to access contents on the filesystem,” Apple explained.

Like the memory flaws, this bug could also be triggered when a browser visits a maliciously crafted website, though instead it could compromise user information on the filesystem of the affected machine.

Finally, Apple credited Zachary Durber of Moodle with discovering a bug that could allow an attacker to spoof Safari’s interface.

WordPress releases latest fix for cross-site scripting (XSS) flaws

Although unrelated, the hugely popular blog platform WordPress released a security update to fix cross-site scripting (XSS) flaws that could be used to attack Safari or any other browser.

WordPress version 4.2.1 was released a week ago to fix critical XSS flaws, but it also contained another potentially more serious XSS bug that stemmed from an unnecessary HTML file in the Genericons icon font package. Any plugin or theme that used the affected HTML file was affected, which has left millions of websites and their visitors exposed to potential attacks.

One of the affected themes was Twenty Fifteen, which was notable because it shipped as a default in WordPress. Security researcher Robert Abela from Netsparker discovered that Twenty Fifteen contained a Document Object Model (DOM) based cross-site scripting vulnerability.

DOM XSS attacks are executed in the browser rather than on the server side. Security firm Sucuri noted that DOM-based XSS are hard to exploit but at the same time “very tricky” to block, highlighting that its own web application firewall couldn’t prevent it. The firm said that there was an attack for the Twenty Fifteen bug in the wild.

The issue however has been fixed in all affected themes and plugins, WordPress said.

“All affected themes and plugins hosted on (including the Twenty Fifteen default theme) have been updated today by the WordPress security team to address this issue by removing this nonessential file. To help protect other Genericons usage, WordPress 4.2.2 proactively scans the wp-content directory for this HTML file and removes it.

This article is brought to you by Enex TestLab, content directors for CSO Australia.

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