Unpatched Magento Flaw Exposes Online Stores to Attacks

Magento, the popular e-commerce platform used by more than 250,000 merchants worldwide, is affected by a potentially serious vulnerability that can be exploited to hijack online stores, researchers warned.

The flaw was found by DefenseCode in November and reported to Magento via the company’s Bugcrowd-based bug bounty program. The vendor indicated at the time that it had been aware of the issue, but it still hasn’t addressed it. After its attempts to obtain a status update on the vulnerability failed, DefenseCode decided to make its findings public.

The vulnerability is related to a feature that allows users to add Vimeo video content for an existing product. When a video is added, Magento automatically retrieves a preview image via a POST request.

This request method can be changed from POST to GET, allowing an attacker to launch a cross-site request forgery (CSRF) attack and upload an arbitrary file. While invalid image files are not allowed, the file is still saved on the server before it is validated.

The location of the file can be easily determined, enabling a hacker to upload a malicious PHP script to the server. In order to achieve remote code execution, the attacker also needs to upload a .htaccess file to the same directory.

For the attack to work, a hacker needs to convince a user with access to the shop’s administration panel, regardless of their role and permissions, to access a specially crafted web page that triggers the CSRF attack.

Researchers warned that successful exploitation of the vulnerability can allow an attacker to take complete control of a targeted system, including gain access to sensitive customer information stored in the compromised store’s database.

“Full administrative access is not required to exploit this vulnerability as any Magento administrative panel user regardless of assigned roles and permissions can access the remote image retrieval functionality. Therefore, gaining a low privileged access can enable the attacker to compromise the whole system or at very least, the database (e.g. traversing to /app/etc/env.php to grab the database password),” DefenseCode wrote in its advisory.

The latest security updates were released by Magento developers in February, when they addressed a critical remote code execution vulnerability that allegedly affected only few systems.

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Related: Magento Malware Hides Stolen Card Data in Image Files

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Eduard Kovacs is an international correspondent for 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.

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