Using local sensitive methods on data that should be interpreted locale independently can produce unexpected results. Locale independent data includes programming language identifiers, protocol keys and HTML tags. It may even be possible to bypass input filters by supplying locale specific data. For example, if a string is converted to uppercase, it may be declared valid, however, further down when changed to lower case, it may result in a black-listed string.

Noncompliant Code Example

This noncompliant code example uses the locale sensitive {{String.toUpperCase()}} method to convert an html tag to uppercase. This produces the string "T?TLE" in the Turkish locale wherein '?' is the Latin capital letter 'I' with a dot above the character \[[API 06|AA. Java References#API 06]\]. 

"title".toUpperCase();

Compliant Solution

This compliant solution explicitly sets the locale to English to avoid the unexpected result.

"title".toUpperCase(Locale.ENGLISH);

Risk Assessment

Automated Detection

TODO

Related Vulnerabilities

Search for vulnerabilities resulting from the violation of this rule on the CERT website.

References

\[[API 06|AA. Java References#API 06]\] Class {{String}}

FIO36-J. Do not create multiple buffered wrappers on an InputStream      09. Input Output (FIO)      09. Input Output (FIO)