diff --git a/addon/init.py b/addon/init.py
index 3c86b8c..78e616a 100644
--- a/addon/init.py
+++ b/addon/init.py
@@ -4,6 +4,7 @@ from pkce_check import PKCEDowngradeChecker
 from ScopeDetection import ScopeDetection
 from csrf_check import CsrfChecker
 from nonce_check import NonceChecker
+from redirect_uri_check import RedirectBypassChecker
 from access_token import AccessTokenScanner
 
 class PKCEAddon:
@@ -64,7 +65,6 @@ class NonceAddon:
             print(f"[ERROR] NonceAddon failed: {e}")
             pass
 
-
 class AccessTokenAddon:
     def __init__(self):
         self.checker = AccessTokenScanner()
@@ -75,6 +75,16 @@ class AccessTokenAddon:
         except Exception as e:
             print(f"[ERROR] AccessToken Addon failed: {e}")
             pass
-    
 
-addons = [PKCEAddon(), ScopeAddon(), CsrfAddon(), NonceAddon(), AccessTokenAddon()]
+class RedirectBypassAddon:
+    def __init__(self):
+        self.checker = RedirectBypassChecker()
+
+    # request 대신 response 로 바꿔 보세요:
+    async def response(self, flow: http.HTTPFlow):
+        try:
+            await self.checker.test(flow)
+        except Exception as e:
+            print(f"[ERROR] RedirectBypass Addon failed: {e}")
+
+addons = [PKCEAddon(), ScopeAddon(), CsrfAddon(), NonceAddon(), AccessTokenAddon(), RedirectBypassAddon()]
diff --git a/addon/redirect_uri_check.py b/addon/redirect_uri_check.py
new file mode 100644
index 0000000..176e537
--- /dev/null
+++ b/addon/redirect_uri_check.py
@@ -0,0 +1,202 @@
+from mitmproxy import http
+import aiohttp
+from urllib.parse import urlparse, parse_qs, urlencode, urlunparse  
+import lib.target as target  
+from lib.report import save_report 
+
+class BypassPayload:
+    """ 우회 패턴 정의 """
+    def __init__(self, name: str, mutate_func, description: str):
+        self.name = name
+        self.mutate = mutate_func #우회 url 만드는 함수
+        self.description = description
+
+
+class RedirectBypassChecker:
+    def __init__(self):
+        """ 우회 페이로드 목록 """
+        self.bypass_payloads = [
+            BypassPayload(
+                name=r"@",
+                mutate_func=self._mutate_pattern1,
+                description=r"@ 기호를 이용한 호스트 우회 공격: evil.com@target.com"
+            ),
+            
+        ]
+        self.session = None
+
+    """ 우회 URL 생성 목록 """
+    # 1. @
+    def _mutate_pattern1(self, original: str) -> str:
+        parsed = urlparse(original)
+        mutated = f"https://evil.com@{parsed.netloc}{parsed.path}"
+        print(f"[redirect_uri_check] original: {original} → mutated: {mutated}")
+        return mutated
+
+    '''aiohttp 세션 생성 (재사용)'''
+    async def _get_session(self):
+        if self.session is None:
+            timeout = aiohttp.ClientTimeout(total=10)
+            self.session = aiohttp.ClientSession(timeout=timeout)
+        return self.session
+
+    '''세션 정리'''
+    async def close_session(self):
+        if self.session:
+            await self.session.close()
+            self.session = None
+
+    """ 우회된 URL에 GET 요청을 보내고, 서버 응답 정보 반환 """
+    async def _send_request(self, url, headers=None):
+        try:
+            session = await self._get_session() # 세션 준비
+            request_headers = headers or {} # 요청 헤더 설정 - headers가 주어지지 않았다면 빈 딕셔너리 사용
+            
+            # 서버에 GET 요청 전송 
+            async with session.get(url, allow_redirects=False, headers=request_headers) as response:
+                return {
+                    'status': response.status,
+                    'location': response.headers.get("Location", ""),
+                    'headers': dict(response.headers)
+                }
+        except Exception as e:
+            print(f"[ERROR] 요청 실패 ({url}): {e}")
+            return {'status': 500, 'location': '', 'headers': {}}
+
+    """ redirect_uri가 기준 도메인(baseUrl)에 속하는지 판단 """
+    def _is_baseline_valid(self, redirect_uri: str, base_url: str) -> bool:
+        try:
+            redirect_parsed = urlparse(redirect_uri)
+            base_parsed = urlparse(base_url)
+            
+            redirect_host = redirect_parsed.hostname
+            base_host = base_parsed.hostname
+            
+            if not redirect_host or not base_host:
+                return False
+            
+            if "@" in redirect_uri:
+                if redirect_host != base_host:
+                    print(f"[ALERT] 우회 공격 탐지: {redirect_host} != {base_host}")
+                    return False
+                
+                at_parts = redirect_uri.split('@')
+                if len(at_parts) > 1:
+                    before_at = at_parts[0]
+                    if '//' in before_at:
+                        potential_domain = before_at.split('//')[-1]
+                        if '.' in potential_domain and potential_domain != base_host:
+                            print(f"[CRITICAL] @ 우회 공격: {potential_domain}@{base_host}")
+                            return False
+            
+            is_valid = (redirect_host == base_host or redirect_host.endswith(f".{base_host}"))
+            return is_valid
+            
+        except Exception as e:
+            print(f"[ERROR] 도메인 검증 실패: {e}")
+            return False
+        
+    """ Location 헤더에서 authorization code 추출 """    
+    def _extract_code_from_location(self, location: str) -> str:
+        if not location:
+            return ""
+        
+        try:
+            parsed = urlparse(location)
+            query = parse_qs(parsed.query)
+            return query.get('code', [''])[0]
+        except:
+            return ""
+
+    """ 메인 테스트 함수 - mitmproxy flow 처리 """
+    async def test(self, flow: http.HTTPFlow):
+        url = flow.request.pretty_url
+        parsed = urlparse(url)
+        query = parse_qs(parsed.query)
+
+        if "redirect_uri" not in query:
+            return
+
+        original_redirect_uri = query["redirect_uri"][0]
+        print(f"[DEBUG] 원본 redirect_uri: {original_redirect_uri}")
+
+        for payload in self.bypass_payloads:
+            try:
+                await self._test_bypass_pattern(
+                    url, query, parsed, original_redirect_uri, payload, headers={}
+                )
+            except Exception as e:
+                print(f"[ERROR] 우회 패턴 테스트 실패 ({payload.name}): {e}")
+                continue
+
+    """ 개별 우회 패턴 테스트 """
+    async def _test_bypass_pattern(self, original_url, query, parsed_url, original_redirect_uri, payload, headers):
+        
+        print(f"[SCAN] 우회 패턴 테스트: {payload.name}")
+        
+        # 우회 URL 생성
+        bypassed_uri = payload.mutate(original_redirect_uri)
+        
+        # 새로운 쿼리 파라미터 구성
+        modified_query = query.copy()
+        modified_query["redirect_uri"] = [bypassed_uri]
+        new_query_string = urlencode(modified_query, doseq=True)
+        test_url = urlunparse(parsed_url._replace(query=new_query_string))
+        
+        # 요청 전송
+        response = await self._send_request(test_url, headers)
+
+        # 응답 분석
+        await self._analyze_response(original_url, test_url, bypassed_uri, response, payload)
+
+    """ 응답 분석 및 취약점 판단 """
+    async def _analyze_response(self, original_url, test_url, bypassed_uri, response, payload):
+        status = response['status']
+        location = response['location']
+        
+        # 리다이렉트 응답이 아니면 스킵
+        if status not in [301, 302, 303, 307, 308]:
+            return
+            
+        # Location 헤더에서 code 추출
+        auth_code = self._extract_code_from_location(location)
+        
+        if auth_code and not self._is_baseline_valid(bypassed_uri, original_url):
+            # 취약점 발견 시에만 로그
+            print(f"[🎯 VULNERABILITY] {payload.name} 우회 성공!")
+            await self._report_vulnerability(original_url, test_url, bypassed_uri, location, auth_code, payload)
+
+
+    """ 취약점 보고서 생성 """
+    async def _report_vulnerability(self, original_url, test_url, bypassed_uri, location, auth_code, payload):
+        # payload가 문자열인지 객체인지 확인
+        if hasattr(payload, 'name'):
+            pattern_name = payload.name
+            pattern_description = payload.description
+        else:
+            pattern_name = str(payload)
+            pattern_description = "Unknown bypass pattern"
+            
+        description = (
+            f"Redirect URI 우회 취약점 발견!\n\n"
+            f"-- 상세 정보 --:\n"
+            f"• 우회 패턴: {pattern_name}\n"
+            f"• 설명: {pattern_description}\n"
+            f"• 원본 URL: {original_url}\n"
+            f"• 우회된 redirect_uri: {bypassed_uri}\n"
+            f"• 테스트 URL: {test_url}\n"
+            f"• 리다이렉트 위치: {location}\n"
+            f"• 발급된 인가 코드: {auth_code[:10]}...\n\n"
+        )
+        
+        report_data = [{
+            "target": target.load(),
+            "status": "CRITICAL",  
+            "title": "Redirect URI Bypass Vulnerability",
+            "description": description,
+            "uri": test_url  # uri 필드 추가
+        }]
+        
+        save_report(report_data)
+        print(f"[🎯 CRITICAL] Redirect URI 우회 취약점 발견 및 보고 완료!")
+        print(f"[INFO] 패턴: {pattern_name}, 우회 URI: {bypassed_uri}")
\ No newline at end of file
diff --git a/runner/proxy.py b/runner/proxy.py
index 7cc2650..d7b856a 100644
--- a/runner/proxy.py
+++ b/runner/proxy.py
@@ -3,4 +3,4 @@ from mitmproxy.tools.main import mitmdump
 
 def run_proxy():
     sys.argv = ["mitmdump", "-s", "./addon/init.py", "--listen-port", "11080"]
-    mitmdump()
+    mitmdump()
\ No newline at end of file