I agree. This seems to be a hard problem, and broader than Perl's CPAN. PyPI, RubyGems, and Npm, for example, all face similar problems:

It might be interesting to compare (and learn from) the security approaches taken by each of these similar mature open source repositories.

Update (2023)

> I'm not (yet) making heavy use of cpan or cpanm tools, and I'm still getting used to them

In case it helps, a detailed example of installing modules from CPAN securely on Linux, using cpan and cpanm, can now be found here.

Thanks to your question, I now keep a long list of Security References (don't want to disappoint the LanX ;-):

In reply to Re^3: cpan/cpanm integrity and authenticy checks concerns by eyepopslikeamosquito
in thread cpan/cpanm integrity and authenticy checks concerns by hrcerq

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