certified What's LINE Login • and many useful features • Password-less Login • QR Code Login on PC • Auto Login on Smart phone/PC • Bot link • Profile+ • etc.
Auto Login › Authentication information is passed from LINE client app and server to your web site or native application securely. › PKCE like mechanism is used › You need not to add additional implementation
wrong implementation of user services › Even if LINE Login platform has no vulnerability, wrong implementation by user service will lead to vulnerability, such as information leak, identity theft. › Vulnerability of LINE Login Platform itself › LINE Login platform developers fix them with the highest priority. 5BSHFUPGUIJTQSFTFOUBUJPO
to LINE Login server 3. ID/password input etc. 5. redirected to yoursite.com with access right to the login user's data 4. allow data access by yousite.com end user
to LINE Login server 3. ID/password input etc. 5. redirected to yoursite.com with access right to the login user's data 4. allow data access by yousite.com end user 6. access the user's data
attacker posts a link to evil.com 2. A victim clicks the link 3. The access_token is sent to the attacker's web server in Referrer header LINE Login server
attacker posts a link to evil.com 2. A victim clicks the link 3. The access_token is sent to the attacker's web server in Referrer header 4. The Attacker can get user information by the access token LINE Login server
Do not expose access token. Instead use, for example, › Server storage › Browser storage with same origin policy, like session storage › Native app storage
'LINE Login' LINE Login yoursite.com 1. yoursite.com issues a state for an user and redirects a request to LINE Login How 'state' works 3. LINE Login redirects the request to yoursite.com w/ the state value
'LINE Login' LINE Login yoursite.com 1. yoursite.com issues a state for an user and redirects a request to LINE Login 4. The user is redirected to yoursite.com How 'state' works 3. LINE Login redirects the request to yoursite.com w/ the state value
'LINE Login' LINE Login yoursite.com 1. yoursite.com issues a state for an user and redirects a request to LINE Login 4. The user is redirected to yoursite.com 5. yoursite.com can reject the request if state value is different from the one issued for the user How 'state' works 3. LINE Login redirects the request to yoursite.com w/ the state value
LINE Login for yoursite.com LINE Login 2. The attacker stops to redirect to yoursite.com yoursite.com If 'state' is fixed value, CSRF attack can be possible.
LINE Login for yoursite.com LINE Login 2. The attacker stops to redirect to yoursite.com yoursite.com 3. The attacker sends a victim the redirect link in some website or e-mail etc. If 'state' is fixed value, CSRF attack can be possible.
LINE Login for yoursite.com LINE Login 2. The attacker stops to redirect to yoursite.com yoursite.com 3. The attacker sends a victim the redirect link in some website or e-mail etc. 4. The victim clicks the link and login to yoursite.com as the attacker If 'state' is fixed value, CSRF attack can be possible.
LINE Login for yoursite.com LINE Login 2. The attacker stops to redirect to yoursite.com yoursite.com 5. The victim uploads sensitive data. The date is stored as the attacker's data since the victim is logging in as the attacker. 3. The attacker sends a victim the redirect link in some website or e-mail etc. 4. The victim clicks the link and login to yoursite.com as the attacker If 'state' is fixed value, CSRF attack can be possible.
should do is 1. Issue a random value as state for each login attempts. 2. Store it securely, for example, as browser cookie. 3. Redirect the login request to LINE Login authorization endpoint with the state parameter. 4. Reject if a state value returned from LINE Login is different from the value issued at step 1.
does 'LINE Login' & get the attacker's user ID 3. The attacker can get/update a victim's data LINE Login yoursite.com 2. call some server API w/ another user ID AAAAAAA
for an attacker to find a valid LINE user ID. 1. LINE User ID is random value generated by cryptographically secure way. 2. LINE User ID is PPID. The ID value for service provider A is different from the ID value for service provider B even if the IDs are for same user.
for an attacker to find a valid LINE user ID. 1. LINE User ID is random value generated by cryptographically secure way. 2. LINE User ID is PPID. The ID value for service provider A is different from the ID value for service provider B even if the IDs are for same user. But this does not mean no risk.
'LINE Login' & get an access token for an attacker's service seems.safe.but.evil.com 2. The attacker's service get the token 3. The attacker calls yoursite.com with the access token LINE Login yoursite.com
'LINE Login' & get an access token for an attacker's service seems.safe.but.evil.com 2. The attacker's service get the token 3. The attacker calls yoursite.com with the access token LINE Login yoursite.com 4. LINE API is called as the victim & the victim's user ID is returned
get the token 1. A victim does 'LINE Login' & get an access token for an attacker's service 3. The attacker calls yoursite.com with the access token 4. Call Token Validation API before other API call Solution seems.safe.but.evil.com LINE Login yoursite.com
API and confirm that returned client_id is your service's client ID curl -v -X GET \ 'https://api.line.me/oauth2/v2.1/verify?access_token=eyJhbGciOiJIUzI1NiJ9.UnQ_o-GP0VtnwDjbK0C8E_NvK...' { "scope":"profile", "client_id":"1440057261", "expires_in":2591659 } https://developers.line.biz/en/reference/social-api/#verify-access-token
Token, you can validate it by yourself. https://developers.line.biz/en/docs/line-login/integrate-line-login/#write-original-code LINE Login provides a utility API and you can use it to verify ID Token. https://developers.line.biz/en/reference/social-api/#verify-id-token curl -v -X POST 'https://api.line.me/oauth2/v2.1/verify' \ -d 'id_token=eyJraWQiOiIxNmUwNGQ0ZTU2NzgzYTc5MmRjYjQ2ODRkOD...&client_id=1440057261' { "iss": "https://access.line.me", "sub": "U1234567890abcdef1234567890abcdef", "aud": "1234567890", "exp": 1504169092, "iat": 1504263657, "nonce": "0987654asdf", "amr": [ "pwd", "linesso", "lineqr" ], "name": "Taro Line", "picture": "https://sample_line.me/aBcdefg123456", "email": "taro.line@example.com" }
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