In the context of cybersecurity and log analysis, such as the Intro to Log Analysis
When an application unsafely uses a user-supplied string as a file path or URL (e.g., in a file_get_contents() call in PHP, or fs.readFile() in Node.js), an attacker can inject file:///proc/self/environ and read the server’s environment variables. callback-url-file-3A-2F-2F-2Fproc-2Fself-2Fenviron
This payload targets the through a vulnerable URL parameter (in this case, callback-url ). In the context of cybersecurity and log analysis,
So, accessing /proc/self/environ allows you to see the environment variables of the process making the request. This can include sensitive information depending on how the process was started and what was set in its environment. in a file_get_contents() call in PHP