CWE-551: Incorrect Behavior Order: Authorization Before Parsing and Canonicalization
Incorrect Behavior Order: Authorization Before Parsing and Canonicalization
Weakness ID: 551 (Weakness Base)
Status: Incomplete
Description
Description Summary
If a web server does not fully parse requested URLs before it
examines them for authorization, it may be possible for an attacker to bypass
authorization protection.
Time of Introduction
Implementation
Demonstrative Examples
Example 1
For instance, the character strings /./ and / both mean current
directory. If /SomeDirectory is a protected directory and an attacker
requests /./SomeDirectory, the attacker may be able to gain access to the
resource if /./ is not converted to / before the authorization check is
performed.
Potential Mitigations
Phase
Description
URL Inputs should be decoded and canonicalized to the application's
current internal representation before being validated and processed for
authorization. Make sure that your application does not decode the same
input twice. Such errors could be used to bypass whitelist schemes by
introducing dangerous inputs after they have been checked.
Description
