Magento 188.8.131.52 PHP Object Injection: Recently, I found a PHP Object Injection (POI) vulnerability in the administrator interface of Magento 184.108.40.206. Magento is an e-commerce software written in PHP that was acquired by Ebay Inc. A bug bounty program is run that attracts with a 10,000$ bounty for remote code execution bugs. A POI vulnerability can lead to such a remote code execution, depending on the gadget chains the attacker is able to trigger.
Sadly I stopped investigating the POI vulnerability and resumed 1 week later – a fatal error. When I continued investigating exploitable gadget chains, Magento pushed an update in the meantime that patches several security issues. The POI is not mentioned anywhere, but it is fixed by replacing the affected unserialize() call with json_decode().
So no bug bounty, but the exploitation is still worth a look at because it includes a hash verification bypass and a cool gadget that allowed full code coverage in gadget chaining. In the end, an attacker can execute arbitrary code on the targeted server. However, administrator privileges are required.