SECURE_NODE // ATHENS_GR
FILE // OPSEC-0xC4  ·  CLEARED FOR PUBLIC

CHARALAMPOS
DOUKAS

Senior offensive security specialist — breaking web apps, APIs, and authentication flows before someone with worse intentions does. 7+ years turning assumptions into proof.

OSCPOSWANATO SECRET Clearance Athens, Greece
[01]

Track Record

Engagements
Findings
Critical
[02]

Attack Surface

01

Web Applications

Full-scope assessments — injection, access control, business-logic abuse, and the things scanners never find.

02

API Security

REST & GraphQL testing, authorization boundary mapping, and broken-object-level access at scale.

03

Auth Flows

OAuth 2.0, PKCE, OIDC and session management — where the deepest, quietest bugs tend to live.

04

Phishing & Social

Authorized phishing and social-engineering ops — pretext design, delivery, and measuring how people and controls actually respond.

05

Internal Network

Post-foothold internal testing — lateral movement, privilege escalation, Active Directory weaknesses, and segmentation gaps.

06

External / Perimeter

Internet-facing exposure — misconfigurations, exposed services, and the soft spots an outside attacker reaches first.

[03]

Credentials

▸ VERIFY ↗
VERIFIED
OffSec · PEN-200

OSCP

Offensive Security Certified Professional — hands-on exploitation under exam conditions.

VERIFY ↗
VERIFIED
OffSec · WEB-200

OSWA

Offensive Security Web Assessor — modern web application attack techniques.

VERIFY ↗
ACTIVE
NATO

SECRET Clearance

Active security clearance — cleared for sensitive engagement work.

IN PROGRESS
OffSec · WEB-300

OSWE

Advanced web exploitation & white-box source-code review. Currently in pursuit.

[04]

Field Research

Technique · API Security · BOLA

The Compressed Blind Spot: BOLA Behind a gzip Request Body

A gzip-compressed POST body hides the object-reference parameter that proves BOLA — Burp renders it as binary noise, one decompression step turns "untestable" into confirmed API1:2023.

BOLAgzipAPI1-2023RequestInspection
Technique · Auth · Account Takeover

2FA Bypass via Password Reset: One Link, Full Admin Takeover

The password reset flow forgot to ask for the second factor — one reset link and a 2FA-protected admin account is fully compromised.

2FAMFABypassAccountTakeover
Technique · Auth · Session Management

Session Not Rebound on Role Switch: Admin Context Leaks to Customer Interface

Sessions rotated on login but not bound to an identity — switching roles in the same browser bleeds admin context through without stealing a single token.

SessionManagementRoleConfusionPrivilegeEscalation
Technique · XSS · E-commerce

Stored XSS: Admin Content Bleeds Into the Public Frontend

Admin panel input stored verbatim and rendered on the public storefront — and HttpOnly on the session cookie did not stop the exploitation chain.

StoredXSSHttpOnlyAdminPanel
Technique · Web Application · Session Management

JWT Session Token Exposed in URL Query Parameter

A signed JWT delivered as a GET query parameter after SSO login — no session binding, no single-use enforcement, and a static jti. Full admin account takeover confirmed by pasting the URL into a clean browser.

JWTSessionHijackingAccountTakeoverBrokenAuth
Technique · File Upload · Workflow Automation

Unrestricted File Upload with Automatic Workflow Deployment

A workflow platform that accepts any file type and deploys it immediately on upload — no content validation, no antivirus scanning, no manual approval step. EICAR test file uploaded and confirmed deployed in a single authenticated POST.

FileUploadRCEWorkflowAbuseMissingValidation
Technique · API Security · IDOR

Unauthenticated IDOR Across Multiple API Endpoints

Five API endpoints on a retail e-commerce platform returning customer profile data, order documents, and benefit records — none with a session ownership check. One valid account was enough to enumerate every other customer in the system.

IDORBrokenAccessControlBOLAAPI Security
Technique · API Security · GraphQL

Unauthenticated GraphQL Endpoint with Introspection Enabled

A CMS content API with GraphQL introspection enabled and no authentication — full schema enumeration in one unauthenticated POST. Two separate subdomain instances, both open.

GraphQLBrokenAccessControlAPI SecurityRecon
Technique · Web Application · CORS

CORS Origin Reflection: When Any Origin Is Trusted

A server that echoes your Origin header back in Access-Control-Allow-Origin — with credentials enabled — means any site on the internet can read authenticated API responses on behalf of any visiting user. One Burp header, one check, complete same-origin policy bypass.

CORSSameOriginPolicyDataExfilBrokenAccessControl
Technique · Business Logic · E-Commerce

When the Price Is Wrong: Business Logic Bugs in a B2B Checkout Flow

A cart quantity of 114 items produces a basket total of €1,057 against line items worth €38,000+. Plus an OTP endpoint that accepts brute-force attempts because the frontend CAPTCHA was never validated server-side. Findings no scanner will ever report.

BusinessLogicPriceManipulationOTPAbuseRetail
Technique · Thick Client · SQL Injection

Thick Client SQL Injection: The Desktop App With the Open Database

Error-based SQLi in a .NET card payments application's login form, plus a database password sitting in plaintext in an SMB-accessible config file. How to intercept thick client traffic and why these applications rarely get tested.

ThickClientSQLiHardcodedCredentialsFintech
Technique · Internal Infrastructure · CVE

Regressing to 2006: CVE-2024-6387 regreSSHion in a Production Network

A critical race condition in OpenSSH's SIGALRM handler — reintroduced in 2020, discovered in 2024 — found on a production internal server alongside BlueKeep. Why the "6–8 hour exploitation window" argument misses the point in an internal network context.

regreSSHionCVE-2024-6387OpenSSHRCE
Technique · Web Application · Session Management

Session Token Persistence: When Logout Means Nothing

Three session management failures that chain into full account takeover: logout doesn't revoke the token, password change doesn't invalidate other sessions, and old password isn't verified — so a stolen session survives every recovery action a user can take.

SessionManagementBrokenAuthAccountTakeover
Technique · Internal Infrastructure · Databases

No Credentials Required: MongoDB Without Auth and Samba Badlock

An internal scan discovers MongoDB on port 27017 with authentication disabled — full read/write to every database, no password. On the same network: a Samba server vulnerable to Badlock, exploitable via the LLMNR relay capability already in hand.

MongoDBBadlockMisconfiguredServicesInternalInfra
Technique · Web Application · Protocol

HTTP Request Smuggling on a Payment Platform

CL.TE desync between a reverse proxy and an Apache PHP backend — confirmed on a payment task queue endpoint. How the framing ambiguity works, why payment platforms are higher-stakes targets, and what the front-end normalization fix actually requires.

RequestSmugglingProtocolDesyncHTTPFintech
Technique · Internal Infrastructure · ICS/SCADA

SCADA in the Blast Radius: SQLi on a Siemens TeleControl Server

An energy operator's SCADA server — Siemens TeleControl Basic, unauthenticated SQL injection — sitting on a flat corporate LAN reachable from any domain workstation, alongside NTLM relay, cleartext SMB credentials, and shared domain passwords.

SCADAICSSQLiNTLMInternalInfra
Technique · File Upload · External Infra

Unrestricted File Upload: When Client-Side Checks Are All You Have

A Windows executable uploaded in place of an identity document on a public unauthenticated registration portal — one Burp intercept, zero server-side validation, files served from web root.

FileUploadRCEExternalInfra
Technique · Internal Infrastructure · Active Directory

Patch Debt Archaeology: Seven Critical Paths in One Network

BlueKeep, EternalBlue, Schannel RCE, FlexNet RCE, two EOL databases — and a backup service account in Domain Admins with a reused local password that cracked in two minutes.

ActiveDirectoryLegacySystemsEternalBlueCredentialReuse
Technique · API Security · Multi-Tenant

Multi-Tenant IDOR: When Your SaaS Platform's Isolation Fails

Sequential transaction IDs with no tenant ownership check — one valid token, any tenant's data. Cross-tenant exposure covering every organisation on the platform, globally.

IDORMultiTenantBOLAAPI Security
Technique · API Security · Auth

The API Endpoint That Gave Away Everyone's Password Hash

A single unauthenticated GET request returned 412 user records with password hashes, salts, roles, and timestamps — no credentials, no session, thirty seconds from first packet.

API SecurityBrokenAccessControlIDOR
Technique · Fintech · Auth

SCA Disabled in Production: A Payment Gateway PSD2 Audit

3DS explicitly off in the SDK config, CVV not validated, withdrawals with no re-auth, and a risk engine that detects fraud then approves it in two seconds.

PSD2SCA3DSFintech
Technique · Internal Infrastructure

EternalBlue to Domain Admin: The Full Chain

One unpatched SMBv1 host, a shared local admin password, and a service account in Domain Admins — full AD compromise in under thirty minutes.

ActiveDirectoryEternalBluePassTheHash
Technique · File Upload

Polyglot Uploads: Beating Magic-Byte Validation

A file that is both a valid PDF and valid HTML walks past upload checks and turns a document form into stored XSS.

UploadPolyglotXSS
Operation · Social

Anatomy of an Authorized Phishing Campaign

An offensive look at how a credible, authorized phishing op is built, launched, and measured.

PhishingRedTeamOSINT
Technique · Auth

Bypassing PKCE

Walking through the implementation gaps that quietly defeat PKCE protection in real OAuth deployments.

OAuthPKCEOIDC
Technique · Client-side

The SVG Keylogger

How an "image" upload becomes a credential-stealing surface — and why your CSP probably is not catching it.

SVGXSSCSP