182
Weakness Ordinalities
Primary :
Applicable Platforms
Language : Not Language-Specific (Prevalence = Undetermined)
Common Consequences
Scope Impact Likelihood
Confidentiality
Integrity
Availability
Read Application Data
Execute Unauthorized Code or Commands
Detection Methods
Automated Static Analysis
Automated static analysis, commonly referred to as Static Application Security Testing (SAST),
can find some instances of this weakness by analyzing source code (or binary/compiled code)
without having to execute it. Typically, this is done by building a model of data flow and control
flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input)
with "sinks" (destinations where the data interacts with external components, a lower layer such
as the OS, etc.)
Effectiveness = High
Potential Mitigations
Phase: Implementation
Carefully check each input parameter against a rigorous positive specification (allowlist) defining
the specific characters and format allowed. All input should be neutralized, not just parameters
that the user is supposed to specify, but all data in the request, including tag attributes, hidden
fields, cookies, headers, the URL itself, and so forth. A common mistake that leads to continuing
XSS vulnerabilities is to validate only fields that are expected to be redisplayed by the site.
We often encounter data from the request that is reflected by the application server or the
application that the development team did not anticipate. Also, a field that is not currently
reflected may be used by a future developer. Therefore, validating ALL parts of the HTTP
request is recommended.
Phase: Implementation
Strategy = Output Encoding
Use and specify an output encoding that can be handled by the downstream component that
is reading the output. Common encodings include ISO-8859-1, UTF-7, and UTF-8. When an
encoding is not specified, a downstream component may choose a different encoding, either
by assuming a default encoding or automatically inferring which encoding is being used, which
can be erroneous. When the encodings are inconsistent, the downstream component might
treat some character or byte sequences as special, even if they are not special in the original
encoding. Attackers might then be able to exploit this discrepancy and conduct injection attacks;
they even might be able to bypass protection mechanisms that assume the original encoding is
CWE Version 4.14
CWE-83: Improper Neutralization of Script in Attributes in a Web Page
CWE-83: Improper Neutralization of Script in Attributes in a Web Page