CWE-558 Use of getlogin() in Multithreaded Application

The product uses the getlogin() function in a multithreaded context, potentially causing it to return incorrect values.

• Integrity, Access Control, Other: Modify Application Data, Bypass Protection Mechanism — Since getlogin() is not reentrant, the contents are not locked out, and the value of the string can be changed by another process. This makes it very risky to use because the username could be changed by other threads.

• [Implementation] Use getlogin_r() instead, which is reentrant, meaning that other processes or threads are locked out from changing the username. • [Architecture and Design] Using names for security purposes is not advised. Names are easy to forge and can have overlapping user IDs, potentially causing confusion or impersonation.

• 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.)