I'm using optional dependencies in some of my scripts and modules to add capability for 'MSWin32' platforms (namely, color with Win32::Console::ANSI and BASH-like command line parsing with Win32::CommandLine). Since these modules are only loadable on 'MSWin32' systems, they are loaded mid-run as optional dependencies. Because they are optional dependencies, they expose the script / module to the ". in @INC" threat vector.

ref: https://dzone.com/articles/security-separation-of-concerns-and-cve-2016-1238 @@ https://archive.is/sKbcs

Currently, the code is usually something like ... 

# Module-Foo.pm
use Term::ANSIColor; () = eval { require Win32::Console::ANSI } if 'MS
+Win32' eq $^O;

[download]
and 
# script-foo.pl
no lib q{.}; # mitigate the ". in @INC" security threat vector when us
+ing optional dependencies
@ARGV = Win32::CommandLine::argv() if eval { require Win32::CommandLin
+e };

[download]

For the module case, the OS/platform check at least narrows down the threat to only 'MSWin32' systems. But, especially in the case of modules, I'd like to remove the threat completely. Unfortunately, `no lib q{.}` is global, and I can't figure out a way to use it without affecting everything.

My other thought for modules was to add the optional dependencies as platform-specific required dependencies, but I'm trying to use the `dzil` build system with both 'Build.PL' and 'Makefile.PL', and I see no compatible method of specifying a platform-specific requirement.

Any thoughts on how to improve this?

In reply to Mitigating ". in @INC" for optional dependencies by Wyrdweaver

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