So phar, so FUD: PHP flaw puts WordPress sites at risk of hacks


Besides Manchester, A newly located WordPress flaw has left installs of the ever-present content material management gadget doubtlessly susceptible to hacking. Security shortcomings let attackers take advantage of weaknesses within WordPress’s PHP framework, allowing already registered users without admin privileges to make the most code, infosec consultancy Secarma has warned.

The hole gives a formerly undiscovered manner to show “unserialization” in the platform’s code, the usage of a mixture of XML outside entity (XXE) assaults, and server-side request forgery (SSRF). To make the attack paintings, a miscreant would need to upload a booby-trapped report onto the target application, then trigger a record operation through a crafted report call (that accesses the information through the phar:// move wrapper), inflicting the goal utility to “unserialize” metadata contained within the file.

The flaw itself could not allow an attacker to break into a targeted device, and handiest expands the scope for mischief once a toehold on centered structures is obtained via some other method. Unserialization of attacker-managed data is a recognized elegance of vulnerability that is vulnerable to lead to the execution of malicious code. German safety researcher Stefan Esser first documented the flaws ten years ago.

Sarma’s research demonstrates a new method that lets an attacker transition from a type of vulnerability not formerly considered awful to 1 that may have an intense impact.

WordPress became informed of the difficulty in February 2017; however, it must take action, consistent with Secarma. PDF technology library TCPDF is similarly susceptible. Content-control device Typo3 became prone until early June – before it launched updates to protect customers.

phar, so FUD: PHP flaw puts WordPress sites at risk of hacks

Secarma’s Sam Thomas offered vulnerability research at Thursday’s BSides cybersecurity conference in Manchester, UK – days after it was first unveiled at Black Hat in Las Vegas last week. His presentation (video beneath) is entitled It’s A PHP Unserialization Vulnerability, Jim, But Not As We Know It. The element between the 30 and 38 minutes concentrates on the WordPress trouble.

A white paper, File Operation Induced Unserialization through the phar:// Stream Wrapper (PDF), explains the issue in more depth. Thomas told El Reg right away after his Manchester gig that he had said the extreme PHP-related vulnerability in WordPress thru HackerOne – which runs its trojan horse bounty program – months in the past. Still, notwithstanding this, the vuln had not been properly resolved. El Reg contacted each WordPress and HackerOne for comment.

We haven’t begun to listen lower back from WordPress. HackerOne confirmed it labored with WordPress but declined to provide anything past that. “Due to our confidentiality obligations to our clients, HackerOne does now not touch upon patron malicious program bounty packages,” the outfit instructed El Reg.

Thomas said the WordPress flaw entails a “diffused vulnerability in thumbnail processing which permits an attacker to reach a ‘file_exists’ name with manage of the begin of the parameter”.

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As things stand, the objective scope of the vulnerability and how smooth it might be to exploit is unclear. Thomas’s presentation contained several caveats overlooked from Secarma’s press launch, which boldly claimed the flaw left “30 in step with a cent of the area’s top 1,000 websites at risk of hacking and data breaches”.

After cautious evaluation and an evaluation of available material, El Reg’s protection table has concluded claims of a “large WordPress vulnerability” are a load of tribble’s testicles. There’s an issue right here; however, the premise that hundreds of thousands of websites are at risk of “entire system compromise” above and beyond the overall widely known risk of running WordPress hasn’t been substantiated with the aid of Secarma, a security commercial enterprise owned through hosting outfit UKFast.

WordPress hasn’t issued a patch, and we have no mitigation records from the CMS dealer. During his presentation, Thomas said that the “issue is most effectively uncovered to authenticated users… They’re simply now not mean if you want to execute [code]”.

Without a restore, WordPress users want to be careful about new debts that are creator degree and above, Thomas cautioned. This money owed must be locked down because the now-public hacking approach may be used to raise privileges to admin. “Ultimately, it’s a problem inside PHP,” Thomas stated, including at some point in a Twitter exchange that “the problem works towards the default configuration of WordPress and PHP, [as far as I know] it isn’t dependent on community or gadget setup”.

Chinese researcher Orange Tsai had located the identical problem Thomas mentioned at some point in his Manchester presentation. WordPress is widely used by bloggers, information shops, and organizations as a content material control machine. To put it mildly, it’s no stranger to safety troubles of one type or some other. ®

Aly Jones
Twitter evangelist. Web fanatic. Lifelong travel nerd. Passionate zombie scholar. Extreme coffee fan. Amateur entrepreneur. Avid beer lover. Had moderate success lecturing about wieners in the UK. Won several awards for short selling clip-on ties in Hanford, CA. Uniquely-equipped for creating marketing channels for cod in Bethesda, MD. Spent a weekend buying and selling Easter candy in Phoenix, AZ. Was quite successful at analyzing tar in the government sector. Have a strong interest in getting to know barbie dolls for fun and profit.