I have a SquirrelMail server setup, and when I play with the mailbox parameter in the following GET query
example.com/src/right_main.php?PG_SHOWALL=0&sort=0&startMessage=1&mailbox=Drafts%2Ftest
I get the following error message (image attached as well):
ERROR: Could not complete request. Query: SELECT "Drafts/test" Reason Given: Mailbox doesn't exist: Drafts/test (0.001 + 0.000 secs).
I was wondering whether this could mean that the site is vulnerable to a SQL injection, and what commands I could try to verify this.