CWE-289 – Authentication Bypass by Alternate Name

Read Time:51 Second

Description

The software performs authentication based on the name of a resource being accessed, or the name of the actor performing the access, but it does not properly check all possible names for that resource or actor.

Modes of Introduction:

– Architecture and Design

 

 

Related Weaknesses

CWE-287

 

Consequences

Access Control: Bypass Protection Mechanism

 

Potential Mitigations

Phase: Architecture and Design

Description: 

Avoid making decisions based on names of resources (e.g. files) if those resources can have alternate names.

Phase: Implementation

Description: 

Phase: Implementation

Description: 

Inputs should be decoded and canonicalized to the application’s current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.

CVE References

  • CVE-2003-0317
    • Protection mechanism that restricts URL access can be bypassed using URL encoding.
  • CVE-2004-0847
    • Bypass of authentication for files using “” (backslash) or “%5C” (encoded backslash).