Security Experts:

Six Flaws Patched With Release of WordPress 4.7.3

WordPress developers announced on Monday the availability of version 4.7.3, a security release that includes patches for six vulnerabilities and 39 maintenance fixes.

WordPress 4.7.3 addresses three cross-site scripting (XSS) flaws that can be exploited via media file metadata, video URLs in YouTube embeds, and taxonomy term names. Chris Andrè Dale, Yorick Koster, Simon P. Briggs, Sucuri researcher Marc Montpas, and a user with the moniker “Delta” have been credited for finding these security holes.

The latest WordPress update also fixes a vulnerability that allows control characters to trick redirect URL validation (reported by Daniel Chatfield), and a bug that can lead to administrators deleting unintended files via the plugin deletion functionality (reported by xuliang).

Another vulnerability patched on Monday, identified by Sipke Mellema, is a cross-site request forgery (CSRF) in the “Press This” function. Exploitation of this flaw can lead to excessive use of server resources and a denial-of-service (DoS) condition.

Mellema and Koster identified the CSRF and XSS vulnerabilities in July 2016 as part of the Summer of Pwnage competition organized by Dutch security firm Securify. The details of the security holes and proof-of-concept (PoC) code have been made public on the Summer of Pwnage website.

According to Koster, he identified two XSS flaws in WordPress’ playlist functionality. An attacker needs to convince an editor or administrator into uploading an MP3 file containing specially crafted metadata. The attacker’s code will get executed when the metadata is processed by the renderTracks() or wp_playlist_shortcode() methods.

Over 100 vulnerabilities have been found in the WordPress core and plugins as part of the Summer of Pwnage project, and most of the issues have been disclosed on March 1, regardless of whether or not they have been fixed.

One WordPress core vulnerability that still has not been patched is a CSRF found by Koster in July 2016. The details of the flaw have not been disclosed, but Cengiz Han Sahin, co-founder of Securify, told SecurityWeek that the unpatched flaw could, in theory, allow an attacker to steal FTP and SSH login credentials. The expert said the vulnerability can have a high impact, but the probability of exploitation is low.

While the developers of the content management system (CMS) claim WordPress 4.7.3 patches six vulnerabilities, there could be other issues they have not disclosed in an effort to protect users. When WordPress 4.7.2 was released on January 26, it appeared to patch only three vulnerabilities, but in reality it also resolved a critical privilege escalation and content injection issue that was disclosed only one week later.

This critical flaw has been exploited in defacements carried out by script kiddies and attacks whose goal was to gain full control of a website.

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.