High-Tech Bridge Security Research Lab discovered a critical Remote File Inclusion (RFI) in Gwolle Guestbook WordPress plugin, which can be exploited by non-authenticated attacker to include remote PHP file and execute arbitrary code on the vulnerable system.
HTTP GET parameter "abspath" is not being properly sanitized before being used in PHP require() function. A remote attacker can include a file named 'wp-load.php' from arbitrary remote server and execute its content on the vulnerable web server. In order to do so the attacker needs to place a malicious 'wp-load.php' file into his server document root and includes server's URL into request:
 High-Tech Bridge Advisory HTB23275 - https://www.htbridge.com/advisory/HTB23275 - PHP File Inclusion in Gwolle Guestbook WordPress Plugin.
 Gwolle Guestbook WordPress Plugin - https://wordpress.org/plugins/gwolle-gb/ - Gwolle Guestbook is the WordPress guestbook you've just been looking for.
 Common Vulnerabilities and Exposures (CVE) - http://cve.mitre.org/ - international in scope and free for public use, CVE? is a dictionary of publicly known information security vulnerabilities and exposures.
 Common Weakness Enumeration (CWE) - http://cwe.mitre.org - targeted to developers and security practitioners, CWE is a formal list of software weakness types.
 ImmuniWeb? SaaS - https://www.htbridge.com/immuniweb/ - hybrid of manual web application penetration test and cutting-edge vulnerability scanner available online via a Software-as-a-Service (SaaS) model.
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