Calibre is a popular open-source e-book management software used by individuals, educators, and organizations to organize and manage their digital book collections. It provides a content server feature allowing remote access to e-book libraries, enabling users to access and manage their collections via web browsers. The software is widely used across various platforms including Windows, macOS, and Linux, making it a versatile tool for managing e-books. The content server in Calibre is especially useful for users who need to access their libraries remotely.
The vulnerability in Calibre allows for unauthenticated remote code execution (RCE) via the content server feature. An attacker can exploit this vulnerability by sending specially crafted requests to the server, which can result in the execution of arbitrary commands. This type of vulnerability is particularly critical as it could allow an attacker to take complete control of the affected system. The vulnerability affects versions of Calibre up to and including 7.14.0.
The vulnerability is present in the content server's handling of requests, particularly in the /interface-data/books-init and /cdb/cmd/list endpoints. When a specially crafted POST request is sent to the server, it allows an attacker to inject and execute arbitrary Python code. The vulnerable parameter is the book_ids field within the JSON body of the request, which is improperly validated, allowing code execution. The server's failure to properly sanitize input results in a critical security flaw that can be exploited remotely without authentication.
Exploitation of this vulnerability could lead to complete system compromise. An attacker could execute arbitrary commands on the server, potentially leading to data theft, system disruptions, or further attacks on connected systems. This could also result in unauthorized access to sensitive information stored within the Calibre server or broader network. In a worst-case scenario, the attacker could install backdoors or malware, making the system part of a larger botnet.
By using the S4E platform, you can stay ahead of potential threats like the Calibre RCE vulnerability. The platform provides continuous monitoring and timely alerts, ensuring that you are aware of any vulnerabilities in your systems. With automated scanning and detailed reports, you can quickly address security issues before they are exploited. Joining the platform gives you access to a wealth of resources and tools designed to enhance your cybersecurity posture, helping you protect your digital assets effectively.
References:
- Update Calibre to a version higher than 7.14.0 as soon as possible.
- Restrict access to the Calibre content server to trusted networks only.
- Implement network-level protections such as firewalls and intrusion detection systems (IDS) to monitor and block malicious activity.
- Regularly audit and review security configurations on systems hosting Calibre.
- Consider disabling the content server feature if it is not necessary for your environment.
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