435
CAPEC-ID Attack Pattern Name
3 Using Leading 'Ghost' Character Sequences to Bypass Input Filters
52 Embedding NULL Bytes
53 Postfix, Null Terminate, and Backslash
64 Using Slashes and URL Encoding Combined to Bypass Validation Logic
71 Using Unicode Encoding to Bypass Validation Logic
72 URL Encoding
78 Using Escaped Slashes in Alternate Encoding
80 Using UTF-8 Encoding to Bypass Validation Logic
120 Double Encoding
267 Leverage Alternate Encoding
CWE-173: Improper Handling of Alternate Encoding
Weakness ID : 173
Structure : Simple
Abstraction : Variant
Description
The product does not properly handle when an input uses an alternate encoding that is valid for the
control sphere to which the input is being sent.
Relationships
The table(s) below shows the weaknesses and high level categories that are related to this
weakness. These relationships are defined as ChildOf, ParentOf, MemberOr and give insight to
similar items that may exist at higher and lower levels of abstraction. In addition, relationships such
as PeerOf and CanAlsoBe are defined to show similar weaknesses that may want to be explored.
Relevant to the view "Research Concepts" (CWE-1000)
Nature Type ID Name Page
ChildOf 172 Encoding Error 433
CanPrecede 289 Authentication Bypass by Alternate Name 703
Applicable Platforms
Language : Not Language-Specific (Prevalence = Undetermined)
Common Consequences
Scope Impact Likelihood
Access Control Bypass Protection Mechanism
Potential Mitigations
Phase: Architecture and Design
Strategy = Input Validation
Avoid making decisions based on names of resources (e.g. files) if those resources can have
alternate names.
Phase: Implementation
Strategy = Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use
a list of acceptable inputs that strictly conform to specifications. Reject any input that does not
strictly conform to specifications, or transform it into something that does. When performing
input validation, consider all potentially relevant properties, including length, type of input, the
full range of acceptable values, missing or extra inputs, syntax, consistency across related
CWE Version 4.14
CWE-173: Improper Handling of Alternate Encoding
CWE-173: Improper Handling of Alternate Encoding