CWE-179 Incorrect Behavior Order: Early Validation

The product validates input before applying protection mechanisms that modify the input.

• Access Control, Integrity: Bypass Protection Mechanism, Execute Unauthorized Code or Commands — An attacker could bypass the protection mechanism by including dangerous inputs that are only produced after the modification (such as canonicalization and cleansing). This can be used to launch various attacks including injection, executing arbitrary code, or causing other unintended behavior.

• [Implementation] 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-2002-0433: List files in web server using "*.ext" • CVE-2003-0332: Product modifies the first two letters of a filename extension after performing a security check, which allows remote attackers to bypass authentication via a filename with a .ats extension instead of a .hts extension. • CVE-2002-0802: Database consumes an extra character when processing a character that cannot be converted, which could remove an escape character from the query and make the application subject to SQL injection attacks. • CVE-2000-0191: Overlaps "fakechild/../realchild" • CVE-2004-2363: Product checks URI for "<" and other literal characters, but does it before hex decoding the URI, so "%3E" and other sequences are allowed. • CVE-2002-0934: Directory traversal vulnerability allows remote attackers to read or modify arbitrary files via invalid characters between two . (dot) characters, which are filtered and result in a ".." sequence. • CVE-2003-0282: Directory traversal vulnerability allows attackers to overwrite arbitrary files via invalid characters between two . (dot) characters, which are filtered and result in a ".." sequence.