I was performing SQL injection through sqlmap and it showed that the parameter is vulnerable but it is only extracting random bits instead of actual data.
I am pasting extracted material here.
[00:12:27] [INFO] the back-end DBMS is MySQL
back-end DBMS: MySQL 8 (MariaDB fork)
[00:12:27] [INFO] fetching current user
[00:12:28] [INFO] resumed: \x021W@{\xf0Q\x07\xf9`x~\x07\xfc/
current user: '1W@{\xf0Q\xf9`x~\xfc/'
[00:12:28] [INFO] fetching server hostname
[00:12:28] [INFO] resumed: b{|5Xfpt\x18\x1df\x02\xa2/\x16p{\x07\xfd\x7f|>
hostname: 'b{|5Xfpt↑↔f☻\xa2/▬p{\xfd⌂|>'
[00:12:28] [INFO] fetching database names
[00:12:28] [INFO] fetching number of databases
[00:12:28] [INFO] resumed: 8930
[00:12:28] [INFO] resumed: 0\xff\x11R6
[00:12:28] [WARNING] running in a single-thread mode. Please consider usage of option '--threads' for faster data retrieval
[00:12:28] [INFO] retrieved:
[00:12:30] [WARNING] in case of continuous data retrieval problems you are advised to try a switch '--no-cast' or switch '--hex'
[00:12:30] [INFO] resumed: ~y\x84\x00\x07\xad\x7f|xx\x07\xfe\x07\xf8M
[00:12:30] [INFO] resumed: \xc1\xfc\x7f\x7f\x07\xf4\xf8@t\x07\xf9\x7f\x07\xf9\x1dx\x07\xe2\x07\xff\xe4\x050\x05_\xf0\x0b`~\x7f@`_`\x03P?\xfc\x80\x03\xe7\x10\x00\x07\xff\xff\xe1
[00:12:30] [INFO] resumed: ~\xff\xf8\x07\x88\x07\x97W\x0c\x07\xe0u\x7f\x04\xb5u|y\x7fP@\x07\xff
[00:12:30] [INFO] retrieved: A"}%
[00:12:51] [INFO] resumed: \x048z
[00:12:51] [INFO] resumed: \x07\xe2\x03\xfc\xff\xe6
[00:12:51] [INFO] resumed: tHh\x07\xc4\x04@\x07\x0ej\x07\xe4
[00:12:51] [INFO] resumed: H`?{
[00:12:51] [INFO] retrieved:
[00:12:53] [INFO] retrieved:
[00:12:55] [INFO] resumed: A
[00:12:55] [INFO] retrieved:
[00:12:57] [INFO] resumed: r\x07\xf6\x04q\xba\xff\xfe\x03\xff\xfe \x04\x7f\xe4{\xff\xc2\xfc\x01\x07\xfc\xe1\x00\x7f@?\xff\x90\x7f\x07\xf5|}\xfd\x00\x00p\xff\xfeo\x07\xfe
[00:12:57] [INFO] resumed: \xfe\x80\x00\x07\xff\xff
[00:12:57] [INFO] resumed: F\x00
[00:12:57] [INFO] resumed: \xff@\x00\xff\x83v`~\x7f
[00:12:57] [INFO] retrieved: ec
[00:13:08] [INFO] retrieved: ;
[00:13:15] [INFO] retrieved:
[00:13:17] [INFO] resumed: 9\x00\x00\x07\x10\x07\x88\x04@? \x00
[00:13:17] [INFO] retrieved:
[00:13:19] [INFO] retrieved: \xfeO\xe8 \xff \xfc\xff\xfb3 \xce\xf2k\xff\xe0rp`` o S\xa1\xab
[00:17:35] [INFO] retrieved: "rAjR^^!
[00:18:16] [INFO] resumed: 8\xe4\x00
[00:18:16] [INFO] retrieved:
[00:18:18] [INFO] retrieved: \xf7X
[00:18:38] [INFO] resumed: \xff\x08
[00:18:38] [INFO] resumed: \x03\xff\xf4\x00\xfe\xb5
[00:18:38] [INFO] resumed: |\x07\xff\x07\xff\x18\x07\xff\xf2\x07\r\xff\x92\x03\xff?\xfe`\x07\xff m~\xe1\x00\x03\xf4\x00\x00
[00:18:38] [INFO] resumed: \x07\xe2\xae`
[00:18:38] [INFO] resumed: \x06\xb0\x00\xff\xf8?\xf9\x00\xff\xf8\x07\x10
[00:18:38] [INFO] resumed: \x07\xff\xc8k.\xfe\xb6C\x07\xe2\x07\xfe\x07\x8f\xfc\x07\xfcrpv|\x07\xfe\x07L\x7f\x18\x07\x10l~\x07\xfc\x07\x01P\xff\xff`\x7f`\xba@
[00:18:38] [INFO] resumed: \x84\x00
[00:18:38] [INFO] retrieved: @^Th r1
[00:19:19] [INFO] retrieved: P
[00:19:25] [INFO] retrieved: p}s
[00:19:41] [INFO] resumed: ~\xff\xf0/
[00:19:41] [INFO] retrieved:
[00:19:43] [INFO] resumed: ?\x1f\xf9/\xff\xff\xf4k0~@\xe0\x83\x07\xf0\x7f\x07\xc2~\x07\x88\x7f\x07\xf8mx\x07\xe2\xff\xf9\xe8\x7f`~>\x041u\xff\xfe\x07\xff\xf9\x04@
[00:19:43] [INFO] resumed: \xf8@\xfa\xbf\xf2
[00:19:43] [INFO] retrieved:
[00:19:45] [INFO] resumed: \xff\xff@
[00:19:45] [INFO] resumed: \x07\xff\xeb\xf4\x00\x00\x07\x87@?\xdd\x00
[00:19:45] [INFO] resumed: \xfc
[00:19:45] [INFO] retrieved:
[00:19:47] [INFO] retrieved: #W@p\x84 ` \xf3,?\xff\xfb\xff\xf0 ` ez \xff\xee~ \xe1\xff\xe1W\xff\xc2#\xcf \xf6f\xf8@pz<\xf59\xc1\xc2?\xff
[00:27:38] [INFO] retrieved: @ \xe8 \xffdh\xff\xf6 \xfc | \xe4u \xfe @ \xe3\xc8k 0 q + \xfe\xc1 \xf1 \xe8 \xff\x84\xfeN \xfc ~\xc2 \xd5 v~x`
Please anyone who could help me with this would be very appreciated.