윤석찬
Offensive Web Security Researcher
Security Contributor of GitHub, Python, Django, FastAPI(Starlette), Apache Airflow, Ruby, Ruby-on-Rails, Java Spring
Education
컴퓨터공학과 졸업예정
경희대학교
취약점분석트랙 수료
차세대 보안리더 양성 프로그램 Best of the Best 6기
해킹방어과 졸업
한국디지털미디어고등학교
Work Experience
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
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
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)
OO부대, OO병
국방부 산하 연구소
- OO 연구 개발
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
사이버공격방어대회
일반부문
국가정보원 주최
Team: 경희대미남해커들 (KHU's hansome hackers)
DEF CON CTF 33
Nautilus Institute 주최
Team: Cold Fusion
🏆 화이트햇 콘테스트
용사부문
국방부 주최
Team: 키보드워리어플랫폼
국방부장관상
CODEGATE
대학부
과학기술정보통신부 주최
Team: 경희대미남해커들 (KHU's hansome hackers)
CODEGATE
대학부
과학기술정보통신부 주최
Team: 경희대미남해커들 (KHU's hansome hackers)
🏆 사이버공격방어대회
공공부문
국가정보원 주최
Team: resilience
국가보안연구소장상
🏆 HACKTHEON SEJONG 전국대학생사이버보안경진대회
세종특별자치시 주최
Team: 라임도둑
국가보안연구소장상
🏆 사이버공격방어대회
공공부문
국가정보원 주최
Team: resilience
국가보안연구소장상
🏆 사이버작전경연대회
학생부
국방부 주최
Team: 윤석찬TV구독과좋아요알림설정까지
사이버작전사령관상
🏆 정보보안경진대회
개인예선
교육부 주최
서울여대 총장상
🏆 정보보안경진대회
단체본선
교육부 주최
Team: 문시우1인팀
교육부 장관상
🏆 정보보안경진대회
단체본선
한국교육학술정보원 주최
Team: 4-day exploit
한국교육학술정보원장상
Disclosed Vulnerabilities
Django
10
Apache Airflow
3
NAVER
3
Ruby on Rails
2
Python
1
FastAPI / Starlette
1
Ruby
1
Java Spring
1
GitHub
1
CVE-2024-7592
Denial of ServiceQuadratic 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.
CVE-2023-36053
Regular Expression Denial of ServicePotential 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.
CVE-2024-24680
Denial of ServicePotential 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.
CVE-2024-27351
Regular Expression Denial of ServicePotential 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.
CVE-2024-21520
Cross-Site ScriptingCross-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.
CVE-2024-41991
Denial of ServicePotential 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.
CVE-2024-53908
SQL InjectionPotential 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.)
CVE-2025-48432
Log InjectionPotential 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.
CVE-2025-64458
Denial of ServicePotential 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.
CVE-2025-64460
Denial of ServicePotential 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.
CVE-2026-1285
Denial of ServicePotential 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.
CVE-2025-62727
Denial of ServiceStarlette 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).
CVE-2024-39877
Code ExecutionApache 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.
CVE-2024-39863
Cross-Site ScriptingApache 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.
CVE-2024-45034
Code ExecutionApache 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.
CVE-2024-41123
Denial of ServiceDoS 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 ]>.
CVE-2024-47887
Regular Expression Denial of ServicePossible 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.
CVE-2024-41128
Regular Expression Denial of ServicePossible 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.
CVE-2024-38809
Denial of ServiceSpring Framework DoS via conditional HTTP request
Applications that parse ETags from "If-Match" or "If-None-Match" request headers are vulnerable to DoS attack.
HackerOne #2646500
Denial of ServiceDoS Vulnerability in GitHub Enterprise
GitHub and GitHub Enterprise are vulnerable to a potential denial-of-service attack caused by a maliciously crafted HTTP request.
NBB-1126
Stored XSSStored XSS
NAVER is vulnerable to a stored-xss caused by a crafted payload.
NBB-1143
SQL InjectionSQL Injection
NAVER is vulnerable to a SQL injection caused by a crafted payload.
NBB-1260
Stored XSSStored XSS
NAVER is vulnerable to a stored XSS caused by a crafted payload.
Talks
“해커의 관점에서 바라본 Django Framework” (한국어)
PyCon KR 2024
“Django Framework N-day 취약점 분석과 시큐어 코딩 가이드” (한국어)
CODEGATE 2023
“Django 프레임워크 1-day analysis” (한국어)
제 26회 해킹캠프
“모던 웹 서비스에서의 버그케이스와 시큐어코딩” (한국어)
STEALIEN Security Semiar
Blog Posts
$5짜리 프롬프트로 $2,163짜리 취약점 찾은 썰
https://new-blog.ch4n3.kr/llm-found-security-issues-from-django-ko/
DEF CON 33 CTF 후기
https://new-blog.ch4n3.kr/def-con-33-review-ko/
Airflow, 과연 안전할까? ー 보안 취약점 리뷰
https://new-blog.ch4n3.kr/is-airflow-truly-safe-ko/
(PyCon KR 2024) 해커의 관점으로 바라본 Django Framework
https://new-blog.ch4n3.kr/pycon-kr-2024/
Django 사용자들이 무조건 Python 버전 업데이트를 해야하는 이유
https://new-blog.ch4n3.kr/cve-2024-7592-kr/
Potential XSS bug found in Django Rest Framework
https://new-blog.ch4n3.kr/restricted-xss-bug-in-django-rest-framework/