A recent study has revealed a critical security vulnerability that affects nearly 12,000 internet-exposed Juniper firewall devices. This vulnerability, known as CVE-2023-36845, was discovered by VulnCheck and is susceptible to remote code execution.
Furthermore, what makes it particularly alarming is that it can be exploited by unauthenticated and remote attackers without the need to create any files on the targeted system. This flaw resides in the J-Web component of Junos OS, and if successfully exploited, it allows threat actors to control specific environment variables.
At the same time, Juniper Networks issued a patch for CVE-2023-36845, along with several other vulnerabilities, in a recent out-of-cycle update, there is still concern about the potential risks.
A proof-of-concept (PoC) exploit, developed by watchTowr, demonstrates the severity of the situation by combining two vulnerabilities, CVE-2023-36846 and CVE-2023-36845, to achieve code execution.
The latest exploit, which primarily impacts older systems, relies solely on CVE-2023-36845 and can be executed using a single cURL command. It leverages PHP’s auto_prepend_file and allow_url_include options, along with the data:// protocol wrapper, to execute arbitrary code.
Security experts emphasize the critical importance of applying patches promptly to mitigate potential threats. While Juniper has reported no successful exploits against its customers, it has detected exploitation attempts in the wild.
Therefore, organizations with unpatched Juniper firewall devices are strongly advised to take immediate action to protect their networks against potential cyberattacks, as firewalls are attractive targets for advanced persistent threats (APTs) looking to gain access to protected networks.
