Ace Your PT0-002 PenTest+ Exam

The VRFY and EXPN commands can be used to enumerate user accounts on an SMTP server, as they are used to verify the existence of users or mailing lists. VRFY (verify) asks the server to confirm that a given user name or address is valid. EXPN (expand) asks the server to expand a mailing list into its individual members. These commands can be used by a penetration tester to identify valid user names or e-mail addresses on the target SMTP server.

the 2>/dev/null is output redirection, it simply sends all the error messages to infinity and beyond preventing any error messages to appear in the terminal session.

The tester is trying to find files with the SUID bit set on the system. The SUID (set user ID) bit is a special permission that allows a file to be executed with the privileges of the file owner, regardless of who runs it. This can be used to perform privileged operations or access restricted resources. A penetration tester can use the find command with the -user and -perm options to search for files owned by a specific user (such as root) and having a specific permission (such as 4000, which indicates the SUID bit is set).

Server-side request forgery (SSRF) is the vulnerability that the tester exploited by querying the provider’s metadata and getting the credentials used by the instance to authenticate itself. SSRF is a type of attack that abuses a web application to make requests to other resources or services on behalf of the web server. This can allow an attacker to access internal or external resources that are otherwise inaccessible or protected. In this case, the tester was able to access the metadata service of the cloud provider, which contains sensitive information about the instance, such as credentials, IP addresses, roles, etc.