윤석찬

윤석찬

Offensive Web Security Researcher

Security Contributor of GitHub, Python, Django, FastAPI(Starlette), Apache Airflow, Ruby, Ruby-on-Rails, Java Spring

Education

2020년 03월 - 2026년 02월

컴퓨터공학과 졸업예정

경희대학교

2017년 07월 - 2018년 05월

취약점분석트랙 수료

차세대 보안리더 양성 프로그램 Best of the Best 6기

2017년 03월 - 2020년 02월

해킹방어과 졸업

한국디지털미디어고등학교

Work Experience

2025년 04월 - 현재 11 개월

Security Researcher

Zellic.io USA

  • Web2 시스템 및 인프라 보안 감사 (source code based auditing)
    • SaaS 플랫폼, 가상자산 거래소 인프라 등 복잡한 Web2 환경에 대한 심층 보안성 검토 수행
    • 비즈니스 로직 취약점, Denial-of-service, SQL Injection 등 고위험군 취약점을 화이트박스/그레이박스 테스트를 통해 식별
  • 보안 컨설팅 및 리스크 관리
    • 클라이언트와 직접 소통하며, 비즈니스 연속성과 보안성 사이의 Trade-off를 고려한 최적의 조치 방안 제안 및 논의
2025년 07월 - 2026년 02월 8 개월

Security Team Member (Volunteer)

Airflow Security Team, Apache Software Foundation USA

  • Airflow 팀에 제보되는 보안 이슈 검토 및 대응
  • 오픈소스 커뮤니티와의 협업
  • ASF 가이드라인에 따라 프로젝트의 보안 수준 유지
2025년 03월 - 2026년 02월 1 년

학부 연구생

PWNLAB (경희대 시스템 보안 연구실, 지도교수: 장대희)

  • 삼성전자 멀티 클라우드 통합 보안 검수 도구 개발 및 웹 서비스 대상 모의해킹
    • AWS, GCP, Azure 플랫폼의 보안 컴플라이언스 260여 개 항목(IAM, Network, Container, Database, Storage, Monitoring, Logging 등)을 자동 진단하는 IaC 기반 스캐너 구현 (Python, FastAPI)
    • 대규모 기업 환경에 적합한 Agentless 아키텍처 및 Multi-thread 병렬 스캔 엔진 설계로 진단 효율성 최적화
    • 삼성전자 소유 웹 서비스 19개를 대상으로 블랙박스 펜테스팅 수행 및 10건의 주요 취약점 식별 -- IDOR(부적절한 데이터 접근), 파일 업로드 필터 우회, XSS 등 중간 파급도 취약점 발굴 및 대응 방안 제시
  • 시스템 해킹 워게임 `pwnable.kr` 소스코드 유지보수 및 기능 개발 (PHP)
2023년 09월 - 2025년 03월 1 년 6 개월

OO부대, OO병

국방부 산하 연구소

  • OO 연구 개발
2020년 07월 - 2023년 06월 3 년

R&D / 선제대응팀, Security Engineer

스틸리언

  • 웹 모의해킹
  • 교육시스템 (Cyber Drill System, Django + React) 개발 및 CTF 운영
  • 사내 기술 관리 도구, 기술블로그, 배포시스템 등 인프라 개발 및 유지보수

CTF Awards

2025

사이버공격방어대회

Finalist

일반부문

국가정보원 주최

Team: 경희대미남해커들 (KHU's hansome hackers)

2025

DEF CON CTF 33

Finalist

Nautilus Institute 주최

Team: Cold Fusion

2024

🏆 화이트햇 콘테스트

1st

용사부문

국방부 주최

Team: 키보드워리어플랫폼

국방부장관상

2023

CODEGATE

Finalist

대학부

과학기술정보통신부 주최

Team: 경희대미남해커들 (KHU's hansome hackers)

2022

CODEGATE

Finalist

대학부

과학기술정보통신부 주최

Team: 경희대미남해커들 (KHU's hansome hackers)

2022

🏆 사이버공격방어대회

2nd

공공부문

국가정보원 주최

Team: resilience

국가보안연구소장상

2022

🏆 HACKTHEON SEJONG 전국대학생사이버보안경진대회

6th

세종특별자치시 주최

Team: 라임도둑

국가보안연구소장상

2021

🏆 사이버공격방어대회

2nd

공공부문

국가정보원 주최

Team: resilience

국가보안연구소장상

2019

🏆 사이버작전경연대회

2nd

학생부

국방부 주최

Team: 윤석찬TV구독과좋아요알림설정까지

사이버작전사령관상

2018

🏆 정보보안경진대회

1st

개인예선

교육부 주최

서울여대 총장상

2018

🏆 정보보안경진대회

1st

단체본선

교육부 주최

Team: 문시우1인팀

교육부 장관상

2017

🏆 정보보안경진대회

1st

단체본선

한국교육학술정보원 주최

Team: 4-day exploit

한국교육학술정보원장상

Disclosed Vulnerabilities

Django Django 10 Apache Airflow Apache Airflow 3 NAVER NAVER 3 Ruby on Rails Ruby on Rails 2 Python Python 1 FastAPI / Starlette FastAPI / Starlette 1 Ruby Ruby 1 Java Spring Java Spring 1 GitHub GitHub 1
Python

CVE-2024-7592

Denial of Service
7.5 High

Quadratic complexity parsing cookies with backslashes

There is a LOW severity vulnerability affecting CPython, specifically the 'http.cookies' standard library module. When parsing cookies that contained backslashes for quoted characters in the cookie value, the parser would use an algorithm with quadratic complexity, resulting in excess CPU resources being used while parsing the value.

Django

CVE-2023-36053

Regular Expression Denial of Service
7.5 High

Potential regular expression denial of service vulnerability in EmailValidator/URLValidator

In Django 3.2 before 3.2.20, 4 before 4.1.10, and 4.2 before 4.2.3, EmailValidator and URLValidator are subject to a potential ReDoS (regular expression denial of service) attack via a very large number of domain name labels of emails and URLs.

Django

CVE-2024-24680

Denial of Service
7.5 High

Potential denial-of-service in intcomma template filter

An issue was discovered in Django 3.2 before 3.2.24, 4.2 before 4.2.10, and Django 5.0 before 5.0.2. The intcomma template filter was subject to a potential denial-of-service attack when used with very long strings.

Django

CVE-2024-27351

Regular Expression Denial of Service
5.3 Medium

Potential regular expression denial-of-service in django.utils.text.Truncator.words()

In Django 3.2 before 3.2.25, 4.2 before 4.2.11, and 5.0 before 5.0.3, the django.utils.text.Truncator.words() method (with html=True) and the truncatewords_html template filter are subject to a potential regular expression denial-of-service attack via a crafted string. NOTE: this issue exists because of an incomplete fix for CVE-2019-14232 and CVE-2023-43665.

Django

CVE-2024-21520

Cross-Site Scripting
6.1 Medium

Cross-Site Scripting (XSS) in browserable API of django-rest-framework

Versions of the package djangorestframework before 3.15.2 are vulnerable to Cross-site Scripting (XSS) via the break_long_headers template filter due to improper input sanitization before splitting and joining with <br> tags.

Django

CVE-2024-41991

Denial of Service
7.5 High

Potential denial-of-service vulnerability in django.utils.html.urlize() and AdminURLFieldWidget

An issue was discovered in Django 5.0 before 5.0.8 and 4.2 before 4.2.15. The urlize and urlizetrunc template filters, and the AdminURLFieldWidget widget, are subject to a potential denial-of-service attack via certain inputs with a very large number of Unicode characters.

Django

CVE-2024-53908

SQL Injection
9.8 Critical

Potential SQL injection in HasKey(lhs, rhs) on Oracle

An issue was discovered in Django 5.1 before 5.1.4, 5.0 before 5.0.10, and 4.2 before 4.2.17. Direct usage of the django.db.models.fields.json.HasKey lookup, when an Oracle database is used, is subject to SQL injection if untrusted data is used as an lhs value. (Applications that use the jsonfield.has_key lookup via __ are unaffected.)

Django

CVE-2025-48432

Log Injection
5.3 Medium

Potential log injection via unescaped request path

An issue was discovered in Django 5.2 before 5.2.3, 5.1 before 5.1.11, and 4.2 before 4.2.23. Internal HTTP response logging does not escape request.path, which allows remote attackers to potentially manipulate log output via crafted URLs. This may lead to log injection or forgery when logs are viewed in terminals or processed by external systems.

Django

CVE-2025-64458

Denial of Service
7.5 High

Potential denial-of-service vulnerability in HttpResponseRedirect and HttpResponsePermanentRedirect on Windows

NFKC normalization in Python is slow on Windows. As a consequence, django.http.HttpResponseRedirect, django.http.HttpResponsePermanentRedirect, and the shortcut django.shortcuts.redirect were subject to a potential denial-of-service attack via certain inputs with a very large number of Unicode characters.

Django

CVE-2025-64460

Denial of Service
7.5 High

Potential denial-of-service vulnerability in XML serializer text extraction

Algorithmic complexity in django.core.serializers.xml_serializer.getInnerText() allows a remote attacker to cause a potential denial-of-service attack triggering CPU and memory exhaustion via specially crafted XML input processed by the XML Deserializer.

Django

CVE-2026-1285

Denial of Service
7.5 High

Potential denial-of-service vulnerability in django.utils.text.Truncator HTML methods

django.utils.text.Truncator.chars() and Truncator.words() methods (with html=True) and the truncatechars_html and truncatewords_html template filters allow a remote attacker to cause a potential denial-of-service via crafted inputs containing a large number of unmatched HTML end tags.

FastAPI / Starlette

CVE-2025-62727

Denial of Service
7.5 High

Starlette vulnerable to O(n^2) DoS via Range header merging

An unauthenticated attacker can send a crafted HTTP Range header that triggers quadratic-time processing in Starlette's FileResponse Range parsing/merging logic. This enables CPU exhaustion per request, causing denial-of-service for endpoints serving files (e.g., StaticFiles or any use of FileResponse).

Apache Airflow

CVE-2024-39877

Code Execution
8.8 High

Apache Airflow: DAG Author Code Execution possibility in airflow-scheduler

Apache Airflow 2.4.0, and versions before 2.9.3, has a vulnerability that allows authenticated DAG authors to craft a doc_md parameter in a way that could execute arbitrary code in the scheduler context, which should be forbidden according to the Airflow Security model.

Apache Airflow

CVE-2024-39863

Cross-Site Scripting
5.4 Medium

Apache Airflow: Potential XSS Vulnerability

Apache Airflow versions before 2.9.3 have a vulnerability that allows an authenticated attacker to inject a malicious link when installing a provider.

Apache Airflow

CVE-2024-45034

Code Execution
8.8 High

Apache Airflow: Authenticated DAG authors could execute code on scheduler nodes

Apache Airflow versions before 2.10.1 have a vulnerability that allows DAG authors to add local settings to the DAG folder and get it executed by the scheduler, where the scheduler is not supposed to execute code submitted by the DAG author.

Ruby

CVE-2024-41123

Denial of Service
7.5 High

DoS vulnerabilities in REXML

The REXML gem before 3.3.2 has some DoS vulnerabilities when it parses an XML that has many specific characters such as whitespace character, >] and ]>.

Ruby on Rails

CVE-2024-47887

Regular Expression Denial of Service
6.0 Medium

Possible ReDoS vulnerability in HTTP Token authentication in Action Controller

There is a possible ReDoS vulnerability in Action Controller's HTTP Token authentication. For applications using HTTP Token authentication via authenticate_or_request_with_http_token or similar, a carefully crafted header may cause header parsing to take an unexpected amount of time, possibly resulting in a DoS vulnerability.

Ruby on Rails

CVE-2024-41128

Regular Expression Denial of Service
6.0 Medium

Possible ReDoS vulnerability in query parameter filtering in Action Dispatch

There is a possible ReDoS vulnerability in the query parameter filtering routines of Action Dispatch. Carefully crafted query parameters can cause query parameter filtering to take an unexpected amount of time, possibly resulting in a DoS vulnerability.

Java Spring

CVE-2024-38809

Denial of Service
5.3 Medium

Spring Framework DoS via conditional HTTP request

Applications that parse ETags from "If-Match" or "If-None-Match" request headers are vulnerable to DoS attack.

GitHub

HackerOne #2646500

Denial of Service

DoS Vulnerability in GitHub Enterprise

GitHub and GitHub Enterprise are vulnerable to a potential denial-of-service attack caused by a maliciously crafted HTTP request.

NAVER

NBB-1126

Stored XSS

Stored XSS

NAVER is vulnerable to a stored-xss caused by a crafted payload.

NAVER

NBB-1143

SQL Injection

SQL Injection

NAVER is vulnerable to a SQL injection caused by a crafted payload.

NAVER

NBB-1260

Stored XSS

Stored XSS

NAVER is vulnerable to a stored XSS caused by a crafted payload.

Talks

“해커의 관점에서 바라본 Django Framework” (한국어)

PyCon KR 2024

2024

“Django Framework N-day 취약점 분석과 시큐어 코딩 가이드” (한국어)

CODEGATE 2023

2023

“Django 프레임워크 1-day analysis” (한국어)

제 26회 해킹캠프

2023

“모던 웹 서비스에서의 버그케이스와 시큐어코딩” (한국어)

STEALIEN Security Semiar

2022

Blog Posts